v3.25.4
Consolidated Schedule of Investments
€ in Thousands, £ in Thousands, shares in Thousands, $ in Thousands
12 Months Ended
Dec. 31, 2025
USD ($)
shares
Dec. 31, 2024
USD ($)
shares
Dec. 31, 2025
CAD ($)
shares
Dec. 31, 2025
EUR (€)
shares
Dec. 31, 2025
GBP (£)
shares
Oct. 31, 2025
USD ($)
Dec. 31, 2024
CAD ($)
shares
Dec. 31, 2023
USD ($)
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Controlled affiliate company investments         Controlled affiliate company investments  
Investment, Type [Extensible Enumeration]   Warrant [Member]         Warrant [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   us-gaap:SecuredOvernightFinancingRateSofrMember         us-gaap:SecuredOvernightFinancingRateSofrMember  
Investments, amortized cost $ 607,574,000 $ 695,240,000            
Investments, fair value $ 578,649,000 $ 642,213,000            
Percent of net assets 222.70% 224.40% 222.70% 222.70% 222.70%   224.40%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Money Market Fair Value $ 5,187,000              
Total investments and money market funds amortized cost 628,622,000 $ 708,489,000            
Total investments and money market funds fair value $ 599,697,000 $ 655,462,000            
Total investments and money market funds percentage 230.80% 229.00% 230.80% 230.80% 230.80%   229.00%  
Qualifying assets required of acquiree at time of acquisition of total assets 70.00% 70.00%            
Qualifying assets of acquired of total assets 79.40% 80.70%            
Investments of net assets 222.70% 224.40%            
Investment Of total assets 94.10% 94.90%            
Unrealized appreciation $ 2,000 $ 20,000            
Unrealized depreciation $ (325,000)              
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:AbCentersAcquisitionCorporationMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Facilities         Health Care Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   0.75%         0.75%  
Spread Above Index   5.25%         5.25%  
Interest Rate   9.78%         9.78%  
Acquisition Date   Sep. 19, 2024            
Maturity Date   Jul. 02, 2031         Jul. 02, 2031  
Principal/Share Amount   $ 78,000            
Investments, amortized cost   78,000            
Investments, fair value   $ 80,000            
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:AbCentersAcquisitionCorporationMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Facilities         Health Care Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   0.75%         0.75%  
Spread Above Index   5.25%         5.25%  
Interest Rate   9.78%         9.78%  
Acquisition Date   Sep. 19, 2024            
Maturity Date   Jul. 02, 2031         Jul. 02, 2031  
Investments, fair value   $ 5,000            
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:AbCentersAcquisitionCorporationMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Facilities         Health Care Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   0.75%         0.75%  
Spread Above Index   5.25%         5.25%  
Interest Rate   9.79%         9.79%  
Acquisition Date   Sep. 19, 2024            
Maturity Date   Jul. 02, 2031         Jul. 02, 2031  
Principal/Share Amount   $ 7,962,000            
Investments, amortized cost   7,866,000            
Investments, fair value   $ 7,919,000            
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:AbCentersAcquisitionCorporationMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Facilities   Health Care Facilities Health Care Facilities Health Care Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 5.25%   5.25% 5.25% 5.25%      
Interest Rate 8.97%   8.97% 8.97% 8.97%      
Acquisition Date Sep. 19, 2024              
Maturity Date Jul. 02, 2031   Jul. 02, 2031 Jul. 02, 2031 Jul. 02, 2031      
Principal/Share Amount $ 408,000              
Investments, amortized cost 405,000              
Investments, fair value $ 409,000              
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:AbCentersAcquisitionCorporationMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Facilities   Health Care Facilities Health Care Facilities Health Care Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 5.25%   5.25% 5.25% 5.25%      
Interest Rate 8.97%   8.97% 8.97% 8.97%      
Acquisition Date Sep. 19, 2024              
Maturity Date Jul. 02, 2031   Jul. 02, 2031 Jul. 02, 2031 Jul. 02, 2031      
Investments, fair value $ 5,000              
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:AbCentersAcquisitionCorporationMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Facilities   Health Care Facilities Health Care Facilities Health Care Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 5.25%   5.25% 5.25% 5.25%      
Interest Rate 8.97%   8.97% 8.97% 8.97%      
Acquisition Date Sep. 19, 2024              
Maturity Date Jul. 02, 2031   Jul. 02, 2031 Jul. 02, 2031 Jul. 02, 2031      
Principal/Share Amount $ 13,039,000              
Investments, amortized cost 12,922,000              
Investments, fair value $ 12,973,000              
Investment, Identifier [Axis]: ABB/Con-cise Optical Group LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ABBCon-ciseOpticalGroupLLCMember whfcl:ABBCon-ciseOpticalGroupLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Health Care Supplies Health Care Supplies Health Care Supplies Health Care Supplies Health Care Supplies   Health Care Supplies  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Spread Above Index 7.50% 7.50% 7.50% 7.50% 7.50%   7.50%  
Interest Rate 11.34% 11.98% 11.34% 11.34% 11.34%   11.98%  
Acquisition Date Feb. 23, 2022 Feb. 23, 2022            
Maturity Date Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028   Feb. 23, 2028  
Principal/Share Amount $ 20,409,000 $ 20,409,000            
Investments, amortized cost 20,227,000 20,142,000            
Investments, fair value $ 20,026,000 $ 19,535,000            
Percent of net assets 7.70% 6.80% 7.70% 7.70% 7.70%   6.80%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: APG Lions Purchaser, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:ApgLionsPurchaserLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Distributors         Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.40%         10.40%  
Acquisition Date   Apr. 26, 2024            
Maturity Date   Apr. 16, 2030         Apr. 16, 2030  
Investments, fair value   $ 15,000            
Investment, Identifier [Axis]: APG Lions Purchaser, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:ApgLionsPurchaserLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Distributors         Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.40%         10.40%  
Acquisition Date   Apr. 26, 2024            
Maturity Date   Apr. 16, 2030         Apr. 16, 2030  
Investments, fair value   $ 6,000            
Investment, Identifier [Axis]: APG Lions Purchaser, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:ApgLionsPurchaserLlcMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Distributors         Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.40%         10.40%  
Acquisition Date   Apr. 26, 2024            
Maturity Date   Apr. 16, 2030         Apr. 16, 2030  
Principal/Share Amount   $ 4,080,000            
Investments, amortized cost   4,027,000            
Investments, fair value   $ 4,070,000            
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ApgLionsPurchaserLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Distributors   Distributors Distributors Distributors      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.39%   9.39% 9.39% 9.39%      
Acquisition Date Apr. 26, 2024              
Maturity Date Apr. 16, 2030   Apr. 16, 2030 Apr. 16, 2030 Apr. 16, 2030      
Investments, fair value $ 15,000              
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ApgLionsPurchaserLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Distributors   Distributors Distributors Distributors      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.39%   9.39% 9.39% 9.39%      
Acquisition Date Apr. 26, 2024              
Maturity Date Apr. 16, 2030   Apr. 16, 2030 Apr. 16, 2030 Apr. 16, 2030      
Investments, fair value $ 6,000              
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ApgLionsPurchaserLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Distributors   Distributors Distributors Distributors      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.39%   9.39% 9.39% 9.39%      
Acquisition Date Apr. 26, 2024              
Maturity Date Apr. 16, 2030   Apr. 16, 2030 Apr. 16, 2030 Apr. 16, 2030      
Principal/Share Amount $ 4,046,000              
Investments, amortized cost 4,002,000              
Investments, fair value $ 4,046,000              
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   Alvaria Holdco [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Application Software         Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   0.75%         0.75%  
Spread Above Index   7.50%         7.50%  
Interest Rate   11.96%         11.96%  
Cash interest rate   5.46%         5.46%  
PIK interest rate   6.50%         6.50%  
Acquisition Date   Mar. 20, 2024            
Maturity Date   May 08, 2028         May 08, 2028  
Principal/Share Amount   $ 1,782,000            
Investments, amortized cost   1,615,000            
Investments, fair value   $ 1,456,000            
Percent of net assets   0.50%         0.50%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan Two                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   Alvaria Holdco [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Application Software         Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   0.75%         0.75%  
Spread Above Index   7.00%         7.00%  
Interest Rate   11.46%         11.46%  
Acquisition Date   Mar. 20, 2024            
Maturity Date   May 08, 2028         May 08, 2028  
Principal/Share Amount   $ 9,600,000            
Investments, amortized cost   9,318,000            
Investments, fair value   $ 3,990,000            
Percent of net assets   1.40%         1.40%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.), First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   Alvaria Holdco [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Application Software         Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   0.75%         0.75%  
Spread Above Index   7.50%         7.50%  
Interest Rate   11.96%         11.96%  
Cash interest rate   6.46%         6.46%  
PIK interest rate   5.50%         5.50%  
Acquisition Date   Mar. 20, 2024            
Maturity Date   May 08, 2028         May 08, 2028  
Principal/Share Amount   $ 1,178,000            
Investments, amortized cost   1,029,000            
Investments, fair value   $ 451,000            
Percent of net assets   0.20%         0.20%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.), First Lien Secured Term Loan Three                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   Alvaria Holdco [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Application Software         Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   0.75%         0.75%  
Spread Above Index   7.00%         7.00%  
Interest Rate   11.46%         11.46%  
Acquisition Date   Mar. 20, 2024            
Maturity Date   May 08, 2028         May 08, 2028  
Principal/Share Amount   $ 2,400,000            
Investments, amortized cost   2,330,000            
Investments, fair value   $ 74,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts Holdings, LLC, Warrants                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsHoldingsLlcMember whfcl:AmericanCraftsHoldingsLlcMember            
Investment, Type [Extensible Enumeration] Warrant [Member] Warrant [Member] Warrant [Member] Warrant [Member] Warrant [Member]   Warrant [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Acquisition Date   Dec. 22, 2022            
Maturity Date   Dec. 22, 2032         Dec. 22, 2032  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts Lc Super Priority First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember            
Investment, Type [Extensible Enumeration] whfcl:SuperPriorityFirstLienSecuredTermLoanMember whfcl:SuperPriorityFirstLienSecuredTermLoanMember whfcl:SuperPriorityFirstLienSecuredTermLoanMember whfcl:SuperPriorityFirstLienSecuredTermLoanMember whfcl:SuperPriorityFirstLienSecuredTermLoanMember   whfcl:SuperPriorityFirstLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.50%         8.50%  
PIK interest rate   12.96%         12.96%  
Acquisition Date   Jul. 25, 2023            
Maturity Date   May 28, 2026         May 28, 2026  
Principal/Share Amount   $ 2,191,000            
Investments, amortized cost   $ 2,094,000            
Investments, fair value               $ 1,878,000
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Interest Rate   8.50%         8.50%  
PIK interest rate   12.96%         12.96%  
Acquisition Date   Jan. 25, 2022            
Maturity Date   May 28, 2026         May 28, 2026  
Principal/Share Amount   $ 1,823,000            
Investments, amortized cost   $ 1,458,000            
Investments, fair value               93,000
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Interest Rate   8.50%         8.50%  
PIK interest rate   12.96%         12.96%  
Acquisition Date   May 28, 2021            
Maturity Date   May 28, 2026         May 28, 2026  
Principal/Share Amount   $ 10,859,000            
Investments, amortized cost   $ 8,720,000            
Investments, fair value               553,000
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts, LC Priority First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember            
Investment, Type [Extensible Enumeration] whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember   whfcl:PriorityFirstLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.50%         8.50%  
PIK interest rate   12.96%         12.96%  
Acquisition Date   Dec. 22, 2022            
Maturity Date   May 28, 2026         May 28, 2026  
Principal/Share Amount   $ 5,876,000            
Investments, amortized cost   $ 5,105,000            
Investments, fair value               3,226,000
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember            
Investment, Type [Extensible Enumeration] whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.50%         8.50%  
PIK interest rate   12.96%         12.96%  
Acquisition Date   May 02, 2024            
Maturity Date   May 28, 2026         May 28, 2026  
Principal/Share Amount   $ 2,485,000            
Investments, amortized cost   2,374,000            
Investments, fair value   $ 373,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan one                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember            
Investment, Type [Extensible Enumeration] whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.50%         8.50%  
PIK interest rate   12.96%         12.96%  
Acquisition Date   Jan. 31, 2024            
Maturity Date   May 28, 2026         May 28, 2026  
Principal/Share Amount   $ 1,287,000            
Investments, amortized cost   $ 1,230,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Apollon Holdings, LLC (d/b/a Apollon Wealth Management, LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ApollonHoldingsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Asset Management & Custody Banks   Asset Management & Custody Banks Asset Management & Custody Banks Asset Management & Custody Banks      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member]   Base Rate [Member] Base Rate [Member] Base Rate [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.33%   9.33% 9.33% 9.33%      
Acquisition Date Jul. 21, 2025              
Maturity Date Jun. 18, 2032   Jun. 18, 2032 Jun. 18, 2032 Jun. 18, 2032      
Principal/Share Amount $ 2,372,000              
Investments, amortized cost 2,339,000              
Investments, fair value $ 2,442,000              
Investment, Identifier [Axis]: Apollon Holdings, LLC (d/b/a Apollon Wealth Management, LLC) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ApollonHoldingsLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Asset Management & Custody Banks   Asset Management & Custody Banks Asset Management & Custody Banks Asset Management & Custody Banks      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.37%   9.37% 9.37% 9.37%      
Acquisition Date Jul. 21, 2025              
Maturity Date Jun. 18, 2032   Jun. 18, 2032 Jun. 18, 2032 Jun. 18, 2032      
Principal/Share Amount $ 6,633,000              
Investments, amortized cost 6,542,000              
Investments, fair value $ 6,632,000              
Investment, Identifier [Axis]: Arcserve Cayman GP LLC (d/b/a Arcserve (USA), LLC) Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanGpLlcMember whfcl:ArcserveCaymanGpLlcMember            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Acquisition Date Jan. 03, 2024 Jan. 03, 2024            
Investment owned shares | shares 663   663 663 663      
Principal/Share Amount   $ 663,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Arcserve Cayman GP LLC (d/b/a Arcserve (USA), LLC) Common Units One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanGpLlcMember              
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember   whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 8.00% 8.00% 8.00% 8.00% 8.00%   8.00%  
PIK interest rate 11.99% 12.67% 11.99% 11.99% 11.99%   12.67%  
Acquisition Date Jan. 03, 2024 Jan. 03, 2024            
Maturity Date Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027   Jan. 04, 2027  
Principal/Share Amount $ 781,000 $ 689,000            
Investments, amortized cost 775,000 677,000            
Investments, fair value $ 1,240,000 $ 1,247,000            
Percent of net assets 0.50% 0.40% 0.50% 0.50% 0.50%   0.40%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) Unsecured Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember            
Investment, Type [Extensible Enumeration] whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Spread Above Index 9.00% 9.00% 9.00% 9.00% 9.00%   9.00%  
PIK interest rate 9.00% 9.00% 9.00% 9.00% 9.00%   9.00%  
Acquisition Date Jan. 03, 2024 Jan. 03, 2024            
Maturity Date Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029   Jul. 02, 2029  
Principal/Share Amount $ 636,000 $ 581,000            
Investments, amortized cost 627,000 569,000            
Investments, fair value $ 636,000 $ 581,000            
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) Unsecured Loan Two                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember            
Investment, Type [Extensible Enumeration] whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Spread Above Index 9.00% 9.00% 9.00% 9.00% 9.00%   9.00%  
Interest Rate 9.00%   9.00% 9.00% 9.00%      
PIK interest rate   9.00%         9.00%  
Acquisition Date Jan. 03, 2024 Jan. 03, 2024            
Maturity Date Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029   Jul. 02, 2029  
Principal/Share Amount $ 650,000 $ 594,000            
Investments, amortized cost 642,000 583,000            
Investments, fair value $ 650,000 $ 594,000            
Percent of net assets 0.30% 0.20% 0.30% 0.30% 0.30%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Arcserve Cayman Topco LP (d/b/a Arcserve (USA), LLC) Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanTopcoLpMember whfcl:ArcserveCaymanTopcoLpMember            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Acquisition Date Jan. 03, 2024 Jan. 03, 2024            
Investment owned shares | shares 663   663 663 663      
Principal/Share Amount   $ 663,000            
Investments, amortized cost $ 19,568,000 19,568,000            
Investments, fair value $ 9,144,000 $ 9,131,000            
Percent of net assets 3.50% 3.20% 3.50% 3.50% 3.50%   3.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Arcserve Cayman Topco LP (d/b/a Arcserve (USA), LLC) Common Units Two                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ArcserveCaymanTopcoLpMember              
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember   whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Investments, fair value $ 9,144,000 $ 9,131,000            
Investment, Identifier [Axis]: Arteriocyte Medical Systems, Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:ArteriocyteMedicalSystemsInc.Member            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Supplies         Health Care Supplies  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.00%         5.00%  
Interest Rate   9.33%         9.33%  
Acquisition Date   Oct. 25, 2023            
Maturity Date   Oct. 18, 2028         Oct. 18, 2028  
Investments, fair value   $ 9,000            
Investment, Identifier [Axis]: Arteriocyte Medical Systems, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:ArteriocyteMedicalSystemsInc.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Supplies         Health Care Supplies  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.00%         5.00%  
Interest Rate   9.33%         9.33%  
Acquisition Date   Oct. 25, 2023            
Maturity Date   Oct. 18, 2028         Oct. 18, 2028  
Principal/Share Amount   $ 4,972,000            
Investments, amortized cost   4,877,000            
Investments, fair value   $ 5,021,000            
Investment, Identifier [Axis]: Atlas Parent, LLC Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:AtlasParentLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Application Software   Application Software Application Software Application Software      
Acquisition Date Oct. 24, 2025              
Principal/Share Amount $ 19,000              
Investments, amortized cost 1,682,000              
Investments, fair value $ 1,853,000              
Percent of net assets 0.70%   0.70% 0.70% 0.70%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Avision Holdings, LLC [Member] Avision Holdings, LLC [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.00% 6.00% 6.00% 6.00% 6.00%   6.00%  
Interest Rate 9.82% 10.48% 9.82% 9.82% 9.82%   10.48%  
Acquisition Date May 31, 2024 May 31, 2024            
Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026   Dec. 15, 2026  
Principal/Share Amount $ 548,000 $ 553,000            
Investments, amortized cost 544,000 545,000            
Investments, fair value $ 546,000 $ 558,000            
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Avision Holdings, LLC [Member] Avision Holdings, LLC [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.00% 6.00% 6.00% 6.00% 6.00%   6.00%  
Interest Rate 9.82% 10.48% 9.82% 9.82% 9.82%   10.48%  
Acquisition Date May 31, 2024 May 31, 2024            
Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026   Dec. 15, 2026  
Principal/Share Amount $ 652,000 $ 658,000            
Investments, amortized cost 647,000 648,000            
Investments, fair value $ 650,000 $ 652,000            
Percent of net assets 0.30% 0.20% 0.30% 0.30% 0.30%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group), Class A LLC Interests                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   Avision Holdings, LLC [Member]            
Investment, Type [Extensible Enumeration]   whfcl:ClassALLCInterestsMember         whfcl:ClassALLCInterestsMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Advertising         Advertising  
Acquisition Date   Dec. 15, 2021            
Investment owned shares | shares   200         200  
Investments, amortized cost   $ 287,000            
Investments, fair value   $ 577,000            
Percent of net assets   0.20%         0.20%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Avision Holdings, LLC Class A LLC Interests                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Avision Holdings, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:ClassALLCInterestsMember   whfcl:ClassALLCInterestsMember whfcl:ClassALLCInterestsMember whfcl:ClassALLCInterestsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Advertising   Advertising Advertising Advertising      
Acquisition Date Dec. 15, 2021              
Investment owned shares | shares 299   299 299 299      
Investments, amortized cost $ 299,000              
Investments, fair value $ 322,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:BBQBuyerLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Household Appliances         Household Appliances  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.50%         1.50%  
Spread Above Index   10.50%         10.50%  
Interest Rate   14.96%         14.96%  
Cash interest rate   12.96%         12.96%  
PIK interest rate   2.00%         2.00%  
Acquisition Date   Dec. 02, 2021            
Maturity Date   Aug. 28, 2025         Aug. 28, 2025  
Principal/Share Amount   $ 2,654,000            
Investments, amortized cost   2,645,000            
Investments, fair value   $ 2,642,000            
Percent of net assets   0.90%         0.90%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:BBQBuyerLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Household Appliances         Household Appliances  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.50%         1.50%  
Spread Above Index   10.50%         10.50%  
Interest Rate   14.96%         14.96%  
Cash interest rate   12.96%         12.96%  
PIK interest rate   2.00%         2.00%  
Acquisition Date   Aug. 28, 2020            
Maturity Date   Aug. 28, 2025         Aug. 28, 2025  
Principal/Share Amount   $ 13,013,000            
Investments, amortized cost   12,972,000            
Investments, fair value   $ 12,955,000            
Percent of net assets   4.50%         4.50%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: BBQ Buyer, LLC Shares                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember            
Investment, Type [Extensible Enumeration] Common Stock [Member] whfcl:SharesMember Common Stock [Member] Common Stock [Member] Common Stock [Member]   whfcl:SharesMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Household Appliances Household Appliances Household Appliances Household Appliances Household Appliances   Household Appliances  
Acquisition Date Aug. 28, 2020 Aug. 28, 2020            
Investment owned shares | shares 1,100   1,100 1,100 1,100      
Principal/Share Amount   $ 1,100,000            
Investments, amortized cost $ 1,100,000 1,100,000            
Investments, fair value $ 1,003,000 $ 907,000            
Percent of net assets 0.40% 0.30% 0.40% 0.40% 0.40%   0.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: BL Products Parent, LP Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:BLProductsParentLPMember whfcl:BLProductsParentLPMember            
Investment, Type [Extensible Enumeration] whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Industrial Machinery & Supplies & Components Industrial Machinery & Supplies & Components Industrial Machinery & Supplies & Components Industrial Machinery & Supplies & Components Industrial Machinery & Supplies & Components   Industrial Machinery & Supplies & Components  
Acquisition Date Feb. 01, 2022 Feb. 01, 2022            
Investment owned shares | shares 733   733 733 733      
Principal/Share Amount   $ 733,000            
Investments, amortized cost $ 788,000 788,000            
Investments, fair value $ 561,000 $ 1,012,000            
Percent of net assets 0.20% 0.40% 0.20% 0.20% 0.20%   0.40%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: BPII-JL Group Holdings LP (d/b/a Juniper Landscaping Holdings LLC) Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:BPII-JLGroupHoldingsLPMember            
Investment, Type [Extensible Enumeration]   whfcl:ClassAUnitsMember         whfcl:ClassAUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Environmental & Facilities Services         Environmental & Facilities Services  
Acquisition Date   Dec. 29, 2021            
Principal/Share Amount   $ 90,000            
Investments, amortized cost   942,000            
Investments, fair value   $ 1,400,000            
Percent of net assets   0.50%         0.50%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: BPII-JL Group Holdings LP Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:BPII-JLGroupHoldingsLPMember              
Investment, Type [Extensible Enumeration] whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services   Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services      
Acquisition Date Dec. 29, 2021              
Investment owned shares | shares 90   90 90 90      
Investments, amortized cost $ 942,000              
Investments, fair value $ 1,645,000              
Percent of net assets 0.60%   0.60% 0.60% 0.60%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Busa Acquisition Co BankCard Usa Merchant Services Inc [Member] Busa Acquisition Co BankCard Usa Merchant Services Inc [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services   Data Processing & Outsourced Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.34% 10.81% 10.34% 10.34% 10.34%   10.81%  
Acquisition Date Apr. 04, 2024 Apr. 04, 2024            
Maturity Date Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029   Mar. 30, 2029  
Principal/Share Amount $ 276,000 $ 459,000            
Investments, amortized cost 270,000 447,000            
Investments, fair value $ 283,000 $ 461,000            
Percent of net assets 0.10% 0.20% 0.10% 0.10% 0.10%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Busa Acquisition Co BankCard Usa Merchant Services Inc [Member] Busa Acquisition Co BankCard Usa Merchant Services Inc [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services   Data Processing & Outsourced Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.29% 10.77% 10.29% 10.29% 10.29%   10.77%  
Acquisition Date Apr. 04, 2024 Apr. 04, 2024            
Maturity Date Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029   Mar. 30, 2029  
Principal/Share Amount $ 7,374,000 $ 7,779,000            
Investments, amortized cost 7,231,000 7,580,000            
Investments, fair value $ 7,331,000 $ 7,691,000            
Percent of net assets 2.80% 2.70% 2.80% 2.80% 2.80%   2.70%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 10.07% 10.59% 10.07% 10.07% 10.07%   10.59%  
Acquisition Date Dec. 21, 2023 Dec. 21, 2023            
Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029   Jan. 02, 2029  
Principal/Share Amount $ 1,873,000 $ 1,502,000            
Investments, amortized cost 1,845,000 1,472,000            
Investments, fair value $ 1,766,000 $ 1,477,000            
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 10.07% 10.61% 10.07% 10.07% 10.07%   10.61%  
Acquisition Date Dec. 21, 2023 Dec. 21, 2023            
Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029   Jan. 02, 2029  
Principal/Share Amount $ 168,000 $ 420,000            
Investments, amortized cost 166,000 412,000            
Investments, fair value $ 118,000 $ 415,000            
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 10.07% 10.61% 10.07% 10.07% 10.07%   10.61%  
Acquisition Date Dec. 21, 2023 Dec. 21, 2023            
Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029   Jan. 02, 2029  
Principal/Share Amount $ 2,956,000 $ 3,033,000            
Investments, amortized cost 2,912,000 2,974,000            
Investments, fair value $ 2,787,000 $ 2,981,000            
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BarrettPurchaserLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Research & Consulting Services   Research & Consulting Services Research & Consulting Services Research & Consulting Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member]   Base Rate [Member] Base Rate [Member] Base Rate [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 5.92%   5.92% 5.92% 5.92%      
Interest Rate 10.02%   10.02% 10.02% 10.02%      
Acquisition Date Jan. 10, 2024              
Maturity Date Nov. 21, 2028   Nov. 21, 2028 Nov. 21, 2028 Nov. 21, 2028      
Principal/Share Amount $ 373,000              
Investments, amortized cost 367,000              
Investments, fair value $ 366,000              
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BarrettPurchaserLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Research & Consulting Services   Research & Consulting Services Research & Consulting Services Research & Consulting Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.82%   9.82% 9.82% 9.82%      
Acquisition Date Jan. 10, 2024              
Maturity Date Nov. 21, 2029   Nov. 21, 2029 Nov. 21, 2029 Nov. 21, 2029      
Principal/Share Amount $ 3,580,000              
Investments, amortized cost 3,523,000              
Investments, fair value $ 3,493,000              
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:BarrettPurchaserLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Research & Consulting Services         Research & Consulting Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   0.75%         0.75%  
Spread Above Index   6.00%         6.00%  
Interest Rate   10.51%         10.51%  
Acquisition Date   Jan. 10, 2024            
Maturity Date   Nov. 21, 2029         Nov. 21, 2029  
Investments, fair value   $ (2,000)            
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:BarrettPurchaserLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Research & Consulting Services         Research & Consulting Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Prime Rate [Member]         Prime Rate [Member]  
Floor   0.75%         0.75%  
Spread Above Index   5.00%         5.00%  
Interest Rate   12.50%         12.50%  
Acquisition Date   Jan. 10, 2024            
Maturity Date   Nov. 21, 2028         Nov. 21, 2028  
Principal/Share Amount   $ 60,000            
Investments, amortized cost   58,000            
Investments, fair value   $ 63,000            
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:BarrettPurchaserLlcMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Research & Consulting Services         Research & Consulting Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   0.75%         0.75%  
Spread Above Index   6.00%         6.00%  
Interest Rate   10.51%         10.51%  
Acquisition Date   Jan. 10, 2024            
Maturity Date   Nov. 21, 2029         Nov. 21, 2029  
Principal/Share Amount   $ 3,617,000            
Investments, amortized cost   3,543,000            
Investments, fair value   $ 3,574,000            
Investment, Identifier [Axis]: Basel U.S. Acquisition Co., Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:BaselU.s.AcquisitionCo.Inc.Member            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Aerospace Sector [Member]         Aerospace Sector [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.50%         5.50%  
Interest Rate   9.94%         9.94%  
Acquisition Date   Sep. 13, 2024            
Maturity Date   Dec. 05, 2028         Dec. 05, 2028  
Investments, fair value   $ 7,000            
Investment, Identifier [Axis]: Basel U.S. Acquisition Co., Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:BaselU.s.AcquisitionCo.Inc.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Aerospace Sector [Member]         Aerospace Sector [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.50%         5.50%  
Interest Rate   9.94%         9.94%  
Acquisition Date   Sep. 13, 2024            
Maturity Date   Dec. 05, 2028         Dec. 05, 2028  
Principal/Share Amount   $ 3,681,000            
Investments, amortized cost   3,633,000            
Investments, fair value   $ 3,675,000            
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:BridgepointHealthcareLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Facilities         Health Care Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.46%         12.46%  
Acquisition Date   Oct. 05, 2021            
Maturity Date   Oct. 05, 2026         Oct. 05, 2026  
Principal/Share Amount   $ 238,000            
Investments, amortized cost   237,000            
Investments, fair value   $ 231,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:BridgepointHealthcareLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Facilities         Health Care Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.46%         12.46%  
Acquisition Date   Oct. 05, 2021            
Maturity Date   Oct. 05, 2026         Oct. 05, 2026  
Principal/Share Amount   $ 8,517,000            
Investments, amortized cost   8,457,000            
Investments, fair value   $ 8,429,000            
Percent of net assets   2.90%         2.90%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Buckeye Acquiror LLC (d/b/a Superior Environmental Solutions, LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:BuckeyeAcquirorLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services   Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Dec. 17, 2025              
Maturity Date Aug. 01, 2029   Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.44% 5.00% 6.44% 6.44% 6.44%   5.00%  
Interest Rate 10.26% 8.45% 10.26% 10.26% 10.26%   8.45%  
Acquisition Date Aug. 09, 2023 Aug. 09, 2023            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Principal/Share Amount $ 2,319,000 $ 2,168,000            
Investments, amortized cost 2,281,000 2,120,000            
Investments, fair value $ 2,323,000 $ 2,183,000            
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.32% 10.96% 10.32% 10.32% 10.32%   10.96%  
Acquisition Date Aug. 09, 2023 Aug. 09, 2023            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Principal/Share Amount $ 370,000 $ 234,000            
Investments, amortized cost 365,000 230,000            
Investments, fair value $ 379,000 $ 248,000            
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.42% 6.42% 6.42% 6.42% 6.42%   6.42%  
Interest Rate 10.23% 10.88% 10.23% 10.23% 10.23%   10.88%  
Acquisition Date Aug. 09, 2023 Aug. 09, 2023            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Principal/Share Amount $ 6,834,000 $ 6,904,000            
Investments, amortized cost 6,733,000 6,774,000            
Investments, fair value $ 6,834,000 $ 6,952,000            
Investment, Identifier [Axis]: CX Holdco LLC Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:CXHoldcoLLCMember whfcl:CXHoldcoLLCMember            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Acquisition Date May 04, 2021 May 04, 2021            
Investment owned shares | shares 1,068   1,068 1,068 1,068      
Principal/Share Amount   $ 1,068,000            
Investments, amortized cost $ 1,116,000 1,116,000            
Investments, fair value $ 218,000 $ 2,232,000            
Percent of net assets 0.10% 0.80% 0.10% 0.10% 0.10%   0.80%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Camarillo Fitness Holdings, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities   Leisure Facilities Leisure Facilities Leisure Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 8.50%   8.50% 8.50% 8.50%      
PIK interest rate 12.83%   12.83% 12.83% 12.83%      
Acquisition Date Jan. 10, 2025              
Maturity Date Sep. 25, 2029   Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029      
Principal/Share Amount $ 1,218,000              
Investments, amortized cost 1,135,000              
Investments, fair value $ 196,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Camarillo Fitness Holdings, LLC [Member] Camarillo Fitness Holdings, LLC [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 8.50% 8.50% 8.50% 8.50% 8.50%   8.50%  
PIK interest rate 12.32% 12.98% 12.32% 12.32% 12.32%   12.98%  
Acquisition Date Sep. 25, 2024 Sep. 25, 2024            
Maturity Date Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029   Sep. 25, 2029  
Principal/Share Amount $ 13,370,000 $ 11,738,000            
Investments, amortized cost 10,231,000 10,269,000            
Investments, fair value $ 5,354,000 $ 10,492,000            
Percent of net assets 2.10% 3.70% 2.10% 2.10% 2.10%   3.70%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Camp Facility Services Holdings, LLC (d/b/a Camp Construction Services, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:CampFacilityServicesHoldingsLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Real Estate Services [Member]         Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Nov. 16, 2021            
Maturity Date   Nov. 16, 2027         Nov. 16, 2027  
Principal/Share Amount   $ 10,424,000            
Investments, amortized cost   10,325,000            
Investments, fair value   $ 9,905,000            
Percent of net assets   3.50%         3.50%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Camp Facility Services Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:CampFacilityServicesHoldingsLLCMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member]   Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Nov. 16, 2021              
Maturity Date Nov. 16, 2027   Nov. 16, 2027 Nov. 16, 2027 Nov. 16, 2027      
Principal/Share Amount $ 10,294,000              
Investments, amortized cost 10,230,000              
Investments, fair value $ 9,781,000              
Percent of net assets 3.80%   3.80% 3.80% 3.80%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Camp Facility Services Parent, LLC Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:CampFacilityServicesParentLLCMember whfcl:CampFacilityServicesParentLLCMember            
Investment, Type [Extensible Enumeration] whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]   Real Estate Services [Member]  
Spread Above Index 10.00% 10.00% 10.00% 10.00% 10.00%   10.00%  
PIK interest rate 10.00% 10.00% 10.00% 10.00% 10.00%   10.00%  
Acquisition Date Nov. 16, 2021 Nov. 16, 2021            
Investment owned shares | shares 15   15 15 15      
Principal/Share Amount   $ 15,000            
Investments, amortized cost $ 840,000 840,000            
Investments, fair value $ 31,000 $ 162,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] true false true true true   false  
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member]   Sterling Overnight Index Average [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 5.50% 6.75% 6.75% 6.75%   5.50%  
Interest Rate 10.59% 10.40% 10.59% 10.59% 10.59%   10.40%  
Cash interest rate 10.34%   10.34% 10.34% 10.34%      
PIK interest rate 0.25%   0.25% 0.25% 0.25%      
Acquisition Date Sep. 11, 2024 Sep. 11, 2024            
Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029   May 04, 2029  
Principal/Share Amount | £         £ 158      
Investments, amortized cost $ 206,000              
Investments, fair value $ 205,000 $ 2,000            
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member] Sterling Overnight Index Average [Member]   Sterling Overnight Index Average [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.65% 5.50% 6.65% 6.65% 6.65%   5.50%  
Interest Rate 10.59% 10.40% 10.59% 10.59% 10.59%   10.40%  
Cash interest rate 10.34%   10.34% 10.34% 10.34%      
PIK interest rate 0.25%   0.25% 0.25% 0.25%      
Acquisition Date Sep. 11, 2024 Sep. 11, 2024            
Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029   May 04, 2029  
Principal/Share Amount   $ 513,000     £ 553      
Investments, amortized cost $ 721,000 665,000            
Investments, fair value $ 717,000 $ 643,000            
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:CennoxInc.Member whfcl:CennoxInc.Member            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 5.50% 6.75% 6.75% 6.75%   5.50%  
Interest Rate 10.60% 10.25% 10.60% 10.60% 10.60%   10.25%  
Cash interest rate 10.35%   10.35% 10.35% 10.35%      
PIK interest rate 0.25%   0.25% 0.25% 0.25%      
Acquisition Date Sep. 11, 2024 Sep. 11, 2024            
Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029   May 04, 2029  
Principal/Share Amount $ 134,000 $ 29,000            
Investments, amortized cost 133,000 29,000            
Investments, fair value $ 129,000 $ 30,000            
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:CennoxInc.Member whfcl:CennoxInc.Member            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Euro Interbank Offered Rate Six Month Term [Member] whfcl:EuroInterbankOfferedRateMember Euro Interbank Offered Rate Six Month Term [Member] Euro Interbank Offered Rate Six Month Term [Member] Euro Interbank Offered Rate Six Month Term [Member]   whfcl:EuroInterbankOfferedRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.00% 5.75% 7.00% 7.00% 7.00%   5.75%  
Interest Rate 9.07% 9.14% 9.07% 9.07% 9.07%   9.14%  
Cash interest rate 8.82%   8.82% 8.82% 8.82%      
PIK interest rate 0.25%   0.25% 0.25% 0.25%      
Acquisition Date Sep. 11, 2024 Sep. 11, 2024            
Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029   May 04, 2029  
Principal/Share Amount   $ 594,000   € 616        
Investments, amortized cost $ 676,000 649,000            
Investments, fair value $ 694,000 $ 611,000            
Investment, Identifier [Axis]: Cennox, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:CennoxInc.Member whfcl:CennoxInc.Member            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 5.50% 6.75% 6.75% 6.75%   5.50%  
Interest Rate 10.89% 10.34% 10.89% 10.89% 10.89%   10.34%  
Cash interest rate 10.64%   10.64% 10.64% 10.64%      
PIK interest rate 0.25%   0.25% 0.25% 0.25%      
Acquisition Date Sep. 11, 2024 Sep. 11, 2024            
Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029   May 04, 2029  
Principal/Share Amount $ 3,508,000 $ 3,350,000            
Investments, amortized cost 3,485,000 3,319,000            
Investments, fair value $ 3,369,000 $ 3,344,000            
Investment, Identifier [Axis]: Chase Products Co. (f/k/a Starco) Second Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ChaseProductsCoMember whfcl:ChaseProductsCoMember            
Investment, Type [Extensible Enumeration] whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Chemicals Diversified Chemicals Diversified Chemicals Diversified Chemicals Diversified Chemicals   Diversified Chemicals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Spread Above Index   12.00%         12.00%  
Interest Rate 9.17%   9.17% 9.17% 9.17%      
Cash interest rate 8.99%   8.99% 8.99% 8.99%      
PIK interest rate 0.18% 12.00% 0.18% 0.18% 0.18%   12.00%  
Acquisition Date Mar. 16, 2023 Mar. 16, 2023            
Maturity Date Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028   Mar. 16, 2028  
Principal/Share Amount $ 3,404,000 $ 3,342,000            
Investments, amortized cost 3,404,000 3,342,000            
Investments, fair value $ 3,404,000 $ 3,342,000           2,793,000
Percent of net assets 1.30% 1.20% 1.30% 1.30% 1.30%   1.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction Materials Construction Materials Construction Materials Construction Materials Construction Materials   Construction Materials  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Base Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 8.38% 8.31% 8.38% 8.38% 8.38%   8.31%  
Interest Rate 13.54% 14.13% 13.54% 13.54% 13.54%   14.13%  
Cash interest rate 9.11% 11.88% 9.11% 9.11% 9.11%   11.88%  
PIK interest rate 4.19% 2.25% 4.19% 4.19% 4.19%   2.25%  
Acquisition Date Dec. 30, 2020 Dec. 30, 2020            
Maturity Date Mar. 31, 2027 Dec. 30, 2025 Mar. 31, 2027 Mar. 31, 2027 Mar. 31, 2027   Dec. 30, 2025  
Principal/Share Amount $ 561,000 $ 632,000            
Investments, amortized cost 561,000 630,000            
Investments, fair value $ 498,000 $ 555,000            
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:CleanChoiceEnergyIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction Materials Construction Materials Construction Materials Construction Materials Construction Materials   Construction Materials  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 8.75% 8.75% 8.75% 8.75% 8.75%   8.75%  
Interest Rate 12.57% 13.21% 12.57% 12.57% 12.57%   13.21%  
Cash interest rate 8.19% 10.96% 8.19% 8.19% 8.19%   10.96%  
PIK interest rate 4.38% 2.25% 4.38% 4.38% 4.38%   2.25%  
Acquisition Date Dec. 30, 2020 Dec. 30, 2020            
Maturity Date Mar. 31, 2027 Dec. 30, 2025 Mar. 31, 2027 Mar. 31, 2027 Mar. 31, 2027   Dec. 30, 2025  
Principal/Share Amount $ 5,124,000 $ 5,711,000            
Investments, amortized cost 5,123,000 5,690,000            
Investments, fair value $ 4,661,000 $ 5,085,000            
Percent of net assets 1.80% 1.80% 1.80% 1.80% 1.80%   1.80%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Clark Restaurant Service, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:ClarkRestaurantServiceLlcMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Food Distributors         Food Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.11%         10.11%  
Acquisition Date   Jun. 14, 2024            
Maturity Date   May 10, 2029         May 10, 2029  
Principal/Share Amount   $ 5,006,000            
Investments, amortized cost   4,919,000            
Investments, fair value   $ 4,993,000            
Investment, Identifier [Axis]: Clark Restaurant Service, LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ClarkRestaurantServiceLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Food Distributors   Food Distributors Food Distributors Food Distributors      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.47%   9.47% 9.47% 9.47%      
Acquisition Date Jun. 14, 2024              
Maturity Date May 10, 2029   May 10, 2029 May 10, 2029 May 10, 2029      
Principal/Share Amount $ 4,956,000              
Investments, amortized cost 4,889,000              
Investments, fair value $ 4,928,000              
Investment, Identifier [Axis]: CleanChoice Energy, Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:CleanChoiceEnergyIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Electric Utilities         Electric Utilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Spread Above Index   7.59%         7.59%  
Interest Rate   12.39%         12.39%  
Acquisition Date   Oct. 12, 2021            
Maturity Date   Oct. 12, 2026         Oct. 12, 2026  
Principal/Share Amount   $ 15,955,000            
Investments, amortized cost   15,802,000            
Investments, fair value   $ 16,032,000            
Percent of net assets   5.60%         5.60%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:CoastalTelevisionBroadcastingGroupLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Broadcasting         Broadcasting  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Dec. 30, 2021            
Maturity Date   Dec. 30, 2026         Dec. 30, 2026  
Investments, fair value   $ 1,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:CoastalTelevisionBroadcastingGroupLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Broadcasting         Broadcasting  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Dec. 30, 2021            
Maturity Date   Dec. 30, 2026         Dec. 30, 2026  
Principal/Share Amount   $ 7,879,000            
Investments, amortized cost   7,808,000            
Investments, fair value   $ 7,832,000            
Percent of net assets   2.70%         2.70%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Colonnade Parent, Inc. (d/b/a Naviga Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:ColonnadeParentIncMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Application Software   Application Software Application Software Application Software      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 1.00%   1.00% 1.00% 1.00%      
Interest Rate 4.77%   4.77% 4.77% 4.77%      
Acquisition Date Jun. 14, 2019              
Maturity Date Sep. 30, 2026   Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026      
Principal/Share Amount $ 301,000              
Investments, amortized cost 287,000              
Investments, fair value $ 158,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Colonnade Parent, Inc. (d/b/a Naviga Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:ColonnadeParentIncMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Application Software   Application Software Application Software Application Software      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 1.00%   1.00% 1.00% 1.00%      
Interest Rate 4.77%   4.77% 4.77% 4.77%      
Acquisition Date Jun. 14, 2019              
Maturity Date Sep. 30, 2026   Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026      
Principal/Share Amount $ 3,667,000              
Investments, amortized cost 2,988,000              
Investments, fair value $ 1,925,000              
Percent of net assets 0.70%   0.70% 0.70% 0.70%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Drew Foam Companies Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:DrewFoamCompaniesIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Building Products         Building Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.00%         6.00%  
Interest Rate   10.48%         10.48%  
Acquisition Date   Nov. 09, 2020            
Maturity Date   Dec. 07, 2026         Dec. 07, 2026  
Principal/Share Amount   $ 13,501,000            
Investments, amortized cost   13,445,000            
Investments, fair value   $ 13,437,000            
Investment, Identifier [Axis]: Drew Foam Companies Inc, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:DrewFoamCompaniesIncMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Building Products   Building Products Building Products Building Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.82%   9.82% 9.82% 9.82%      
Acquisition Date Nov. 09, 2020              
Maturity Date Dec. 07, 2026   Dec. 07, 2026 Dec. 07, 2026 Dec. 07, 2026      
Principal/Share Amount $ 13,358,000              
Investments, amortized cost 13,331,000              
Investments, fair value $ 13,314,000              
Investment, Identifier [Axis]: E-Phoenix Acquisition Co. Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:E-PhoenixAcquisitionCo.Inc.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Research & Consulting Services         Research & Consulting Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.50%         5.50%  
Interest Rate   9.98%         9.98%  
Acquisition Date   Jul. 15, 2021            
Maturity Date   Jun. 23, 2027         Jun. 23, 2027  
Principal/Share Amount   $ 8,342,000            
Investments, amortized cost   8,299,000            
Investments, fair value   $ 8,342,000            
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ElmDebtcoLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering   Construction & Engineering Construction & Engineering Construction & Engineering      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Nov. 20, 2025              
Maturity Date Nov. 14, 2031   Nov. 14, 2031 Nov. 14, 2031 Nov. 14, 2031      
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ElmDebtcoLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering   Construction & Engineering Construction & Engineering Construction & Engineering      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Nov. 20, 2025              
Maturity Date Nov. 14, 2031   Nov. 14, 2031 Nov. 14, 2031 Nov. 14, 2031      
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ElmDebtcoLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering   Construction & Engineering Construction & Engineering Construction & Engineering      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Nov. 20, 2025              
Maturity Date Nov. 14, 2031   Nov. 14, 2031 Nov. 14, 2031 Nov. 14, 2031      
Principal/Share Amount $ 5,543,000              
Investments, amortized cost 5,488,000              
Investments, fair value $ 5,488,000              
Investment, Identifier [Axis]: Eddy Acquisitions, LLC (d/b/a EducationDynamics, LLC) Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:EddyAcquisitionsLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:PreferredUnitsMember         whfcl:PreferredUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Education Services         Education Services  
Spread Above Index   12.00%         12.00%  
Interest Rate   12.00%         12.00%  
Acquisition Date   Sep. 15, 2021            
Principal/Share Amount   $ 167,000            
Investments, amortized cost   $ 167,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Eddy Acquisitions, LLC Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:EddyAcquisitionsLLCMember              
Investment, Type [Extensible Enumeration] whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Education Services   Education Services Education Services Education Services      
Spread Above Index 12.00%   12.00% 12.00% 12.00%      
Interest Rate 12.00%   12.00% 12.00% 12.00%      
Acquisition Date Sep. 15, 2021              
Investment owned shares | shares 167   167 167 167      
Investments, amortized cost $ 167,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] true   true true true      
Investment, Identifier [Axis]: Education Dynamics, LLC Senior Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:SeniorPreferredUnitsMember whfcl:SeniorPreferredUnitsMember whfcl:SeniorPreferredUnitsMember whfcl:SeniorPreferredUnitsMember whfcl:SeniorPreferredUnitsMember   whfcl:SeniorPreferredUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Education Services Education Services Education Services Education Services Education Services   Education Services  
Acquisition Date Sep. 15, 2021 Sep. 15, 2021            
Investment owned shares | shares 167   167 167 167      
Principal/Share Amount   $ 167,000            
Investments, amortized cost $ 167,000 167,000            
Investments, fair value   $ 100,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Education Services Education Services Education Services Education Services Education Services   Education Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Prime Rate [Member] whfcl:SecuredOvernightFinancingRateMember Prime Rate [Member] Prime Rate [Member] Prime Rate [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 6.50% 5.50% 5.50% 5.50%   6.50%  
Interest Rate 12.25% 10.96% 12.25% 12.25% 12.25%   10.96%  
Acquisition Date Sep. 15, 2021 Sep. 15, 2021            
Maturity Date Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027   Sep. 15, 2027  
Principal/Share Amount $ 360,000              
Investments, amortized cost 358,000              
Investments, fair value $ 320,000 $ (51,000)            
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Education Services Education Services Education Services Education Services Education Services   Education Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.32% 10.96% 10.32% 10.32% 10.32%   10.96%  
Acquisition Date Sep. 15, 2021 Sep. 15, 2021            
Maturity Date Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027   Sep. 15, 2027  
Principal/Share Amount $ 12,592,000 $ 13,089,000            
Investments, amortized cost 12,532,000 12,989,000            
Investments, fair value $ 12,137,000 $ 12,449,000            
Percent of net assets 4.70% 4.30% 4.70% 4.70% 4.70%   4.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Event Services America, Inc. (d/b/a Contemporary Services Corporation) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:EventServicesAmericaIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Security & Alarm Services         Security & Alarm Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.75%         6.75%  
Interest Rate   11.11%         11.11%  
Acquisition Date   Jan. 31, 2024            
Maturity Date   Jan. 31, 2029         Jan. 31, 2029  
Principal/Share Amount   $ 7,000,000            
Investments, amortized cost   6,857,000            
Investments, fair value   $ 7,070,000            
Percent of net assets   2.50%         2.50%  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: FGI Acquisition Corp. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:FgiAcquisitionCorpMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Commodity Chemicals         Commodity Chemicals  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.98%         10.98%  
Acquisition Date   Oct. 28, 2019            
Maturity Date   Oct. 29, 2026         Oct. 29, 2026  
Principal/Share Amount   $ 16,026,000            
Investments, amortized cost   15,765,000            
Investments, fair value   $ 16,026,000            
Percent of net assets   5.60%         5.60%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: FloWorks International LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Distributors Distributors Distributors Distributors Distributors   Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Spread Above Index 4.75% 5.75% 4.75% 4.75% 4.75%   5.75%  
Interest Rate 8.57% 10.40% 8.57% 8.57% 8.57%   10.40%  
Acquisition Date Dec. 12, 2024 Dec. 12, 2024            
Maturity Date Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031   Nov. 26, 2031  
Principal/Share Amount $ 667,000              
Investments, amortized cost 661,000              
Investments, fair value $ 663,000              
Investment, Identifier [Axis]: FloWorks International LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Distributors Distributors Distributors Distributors Distributors   Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Spread Above Index 4.75% 4.75% 4.75% 4.75% 4.75%   4.75%  
Interest Rate 8.57% 9.27% 8.57% 8.57% 8.57%   9.27%  
Acquisition Date Dec. 12, 2024 Dec. 12, 2024            
Maturity Date Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031   Nov. 26, 2031  
Principal/Share Amount $ 5,293,000 $ 5,333,000            
Investments, amortized cost 5,248,000 5,280,000            
Investments, fair value $ 5,262,000 $ 5,281,000            
Investment, Identifier [Axis]: Foodservices Brand Group, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:FoodservicesBrandGroupLlcMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Distributors         Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.62%         12.62%  
Acquisition Date   Nov. 22, 2022            
Maturity Date   Dec. 09, 2025         Dec. 09, 2025  
Principal/Share Amount   $ 357,000            
Investments, amortized cost   357,000            
Investments, fair value   $ 321,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 6.75% 6.75% 6.75% 6.75%   6.75%  
Interest Rate 10.57% 11.23% 10.57% 10.57% 10.57%   11.23%  
Acquisition Date Mar. 11, 2022 Mar. 11, 2022            
Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026   Dec. 15, 2026  
Principal/Share Amount $ 2,993,000 $ 3,023,000            
Investments, amortized cost 2,981,000 3,000,000            
Investments, fair value $ 2,993,000 $ 3,023,000            
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 6.75% 6.75% 6.75% 6.75%   6.75%  
Interest Rate 10.69% 11.23% 10.69% 10.69% 10.69%   11.23%  
Acquisition Date Feb. 18, 2022 Feb. 18, 2022            
Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026   Dec. 15, 2026  
Principal/Share Amount $ 619,000              
Investments, amortized cost 617,000              
Investments, fair value $ 619,000 $ 5,000            
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 6.75% 6.75% 6.75% 6.75%   6.75%  
Interest Rate 10.57% 11.23% 10.57% 10.57% 10.57%   11.23%  
Acquisition Date Feb. 18, 2022 Feb. 18, 2022            
Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026   Dec. 15, 2026  
Principal/Share Amount $ 8,914,000 $ 9,007,000            
Investments, amortized cost 8,880,000 8,937,000            
Investments, fair value $ 8,914,000 $ 9,007,000            
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Four Winds Health, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Facilities   Health Care Facilities Health Care Facilities Health Care Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 7.00%   7.00% 7.00% 7.00%      
Interest Rate 10.67%   10.67% 10.67% 10.67%      
Acquisition Date Jul. 31, 2025              
Maturity Date Jul. 31, 2029   Jul. 31, 2029 Jul. 31, 2029 Jul. 31, 2029      
Principal/Share Amount $ 250,000              
Investments, amortized cost 248,000              
Investments, fair value $ 272,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Four Winds Health, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Facilities   Health Care Facilities Health Care Facilities Health Care Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 7.00%   7.00% 7.00% 7.00%      
Interest Rate 10.67%   10.67% 10.67% 10.67%      
Acquisition Date Jul. 31, 2025              
Maturity Date Jul. 31, 2029   Jul. 31, 2029 Jul. 31, 2029 Jul. 31, 2029      
Investments, fair value $ 8,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Four Winds Health, LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Facilities   Health Care Facilities Health Care Facilities Health Care Facilities      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 7.00%   7.00% 7.00% 7.00%      
Interest Rate 10.67%   10.67% 10.67% 10.67%      
Acquisition Date Jul. 31, 2025              
Maturity Date Jul. 31, 2029   Jul. 31, 2029 Jul. 31, 2029 Jul. 31, 2029      
Principal/Share Amount $ 4,364,000              
Investments, amortized cost 4,286,000              
Investments, fair value $ 4,343,000              
Percent of net assets 1.70%   1.70% 1.70% 1.70%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Future Payment Technologies, LP First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:FuturePaymentTechnologiesLPMember whfcl:FuturePaymentTechnologiesLPMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services Data Processing & Outsourced Services   Data Processing & Outsourced Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 8.25% 8.25% 8.25% 8.25% 8.25%   8.25%  
Interest Rate 12.22% 12.90% 12.22% 12.22% 12.22%   12.90%  
Acquisition Date Dec. 23, 2016 Dec. 23, 2016            
Maturity Date Dec. 07, 2026 Dec. 05, 2025 Dec. 07, 2026 Dec. 07, 2026 Dec. 07, 2026   Dec. 05, 2025  
Principal/Share Amount $ 19,175,000 $ 20,420,000            
Investments, amortized cost 19,160,000 20,382,000            
Investments, fair value $ 19,175,000 $ 20,420,000            
Percent of net assets 7.40% 7.10% 7.40% 7.40% 7.40%   7.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:G2LatherAcquisitionCorp.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Personal Products   Personal Products Personal Products Personal Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.72%   8.72% 8.72% 8.72%      
Acquisition Date Mar. 05, 2025              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Investments, fair value $ 10,000              
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:G2LatherAcquisitionCorp.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Personal Products   Personal Products Personal Products Personal Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.72%   8.72% 8.72% 8.72%      
Acquisition Date Mar. 05, 2025              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Investments, fair value $ 4,000              
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:G2LatherAcquisitionCorp.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Personal Products   Personal Products Personal Products Personal Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.72%   8.72% 8.72% 8.72%      
Acquisition Date Mar. 05, 2025              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Principal/Share Amount $ 3,900,000              
Investments, amortized cost 3,850,000              
Investments, fair value $ 3,873,000              
Investment, Identifier [Axis]: GTT Communications Global, LLC (d/b/a GTT Communications, Inc.), First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:GttCommunicationsGlobalLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Integrated Telecommunication Services   Integrated Telecommunication Services Integrated Telecommunication Services Integrated Telecommunication Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.73%   9.73% 9.73% 9.73%      
Acquisition Date Apr. 15, 2025              
Maturity Date Apr. 15, 2031   Apr. 15, 2031 Apr. 15, 2031 Apr. 15, 2031      
Principal/Share Amount $ 15,283,000              
Investments, amortized cost 15,014,000              
Investments, fair value $ 15,129,000              
Percent of net assets 5.80%   5.80% 5.80% 5.80%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Geo Logic Systems Ltd.First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:GeoLogicSystemsLtdMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Data Processing & Outsourced Services         Data Processing & Outsourced Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:CanadianOvernightRepoRateAverageMember         whfcl:CanadianOvernightRepoRateAverageMember  
Floor   1.00%         1.00%  
Spread Above Index   6.00%         6.00%  
Interest Rate   9.49%         9.49%  
Acquisition Date   Jan. 22, 2020            
Maturity Date   Dec. 21, 2026         Dec. 21, 2026  
Investments, fair value   $ 2,000            
Investment, Identifier [Axis]: Geo Logic Systems Ltd.First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:GeoLogicSystemsLtdMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Data Processing & Outsourced Services         Data Processing & Outsourced Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:CanadianOvernightRepoRateAverageMember         whfcl:CanadianOvernightRepoRateAverageMember  
Floor   1.00%         1.00%  
Spread Above Index   6.00%         6.00%  
Interest Rate   9.49%         9.49%  
Acquisition Date   Jan. 22, 2020            
Maturity Date   Dec. 21, 2026         Dec. 21, 2026  
Principal/Share Amount   $ 18,415,000            
Investments, amortized cost   14,234,000            
Investments, fair value   $ 12,883,000            
Investment, Identifier [Axis]: Gulf Winds International Acquisition, LLC (d/b/a Gulf Winds International, Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.00% 7.50% 7.00% 7.00% 7.00%   7.50%  
Interest Rate 10.72% 11.95% 10.72% 10.72% 10.72%   11.95%  
Acquisition Date Dec. 16, 2022 Dec. 16, 2022            
Maturity Date Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028   Dec. 18, 2028  
Principal/Share Amount $ 605,000 $ 453,000            
Investments, amortized cost 596,000 444,000            
Investments, fair value $ 584,000 $ 447,000            
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Gulf Winds International Acquisition, LLC (d/b/a Gulf Winds International, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.00% 7.60% 7.00% 7.00% 7.00%   7.60%  
Interest Rate 10.72% 11.96% 10.72% 10.72% 10.72%   11.96%  
Cash interest rate 9.72%   9.72% 9.72% 9.72%      
PIK interest rate 1.00%   1.00% 1.00% 1.00%      
Acquisition Date Dec. 16, 2022 Dec. 16, 2022            
Maturity Date Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028   Dec. 18, 2028  
Principal/Share Amount $ 8,956,000 $ 8,994,000            
Investments, amortized cost 8,820,000 8,811,000            
Investments, fair value $ 8,697,000 $ 8,857,000            
Percent of net assets 3.30% 3.10% 3.30% 3.30% 3.30%   3.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: H I G Camarillo, LP, Limited Partners Interests                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Controlled affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Controlled affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:HIGCamarilloLpMember whfcl:HIGCamarilloLpMember            
Investment, Type [Extensible Enumeration] whfcl:LimitedPartnerInterestsMember whfcl:LimitedPartnerInterestsMember whfcl:LimitedPartnerInterestsMember whfcl:LimitedPartnerInterestsMember whfcl:LimitedPartnerInterestsMember   whfcl:LimitedPartnerInterestsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Acquisition Date Sep. 25, 2024 Sep. 25, 2024            
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]   Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Base Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.22% 6.97% 6.22% 6.22% 6.22%   6.97%  
Interest Rate 10.55% 11.29% 10.55% 10.55% 10.55%   11.29%  
Acquisition Date Feb. 18, 2022 Feb. 18, 2022            
Maturity Date Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026   Oct. 19, 2026  
Principal/Share Amount $ 1,154,000 $ 1,395,000            
Investments, amortized cost 1,150,000 1,384,000            
Investments, fair value $ 1,154,000 $ 1,354,000            
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]   Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 10.27% 11.02% 10.27% 10.27% 10.27%   11.02%  
Acquisition Date Feb. 18, 2022 Feb. 18, 2022            
Maturity Date Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026   Oct. 19, 2026  
Principal/Share Amount $ 700,000 $ 483,000            
Investments, amortized cost 698,000 480,000            
Investments, fair value $ 701,000 $ 455,000            
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]   Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 10.27% 11.02% 10.27% 10.27% 10.27%   11.02%  
Acquisition Date Dec. 28, 2021 Dec. 28, 2021            
Maturity Date Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026   Oct. 19, 2026  
Principal/Share Amount $ 4,602,000 $ 5,563,000            
Investments, amortized cost 4,588,000 5,523,000            
Investments, fair value $ 4,602,000 $ 5,395,000            
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.00% 5.50% 6.00% 6.00% 6.00%   5.50%  
Interest Rate 9.83% 10.35% 9.83% 9.83% 9.83%   10.35%  
Acquisition Date Feb. 17, 2022 Feb. 17, 2022            
Maturity Date Jun. 14, 2027 Jun. 15, 2026 Jun. 14, 2027 Jun. 14, 2027 Jun. 14, 2027   Jun. 15, 2026  
Investments, fair value $ 2,000 $ 4,000            
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.00% 5.50% 6.00% 6.00% 6.00%   5.50%  
Interest Rate 9.83% 10.35% 9.83% 9.83% 9.83%   10.35%  
Acquisition Date Feb. 17, 2022 Feb. 17, 2022            
Maturity Date Jun. 14, 2027 Jun. 15, 2026 Jun. 14, 2027 Jun. 14, 2027 Jun. 14, 2027   Jun. 15, 2026  
Principal/Share Amount $ 3,271,000 $ 3,307,000            
Investments, amortized cost 3,262,000 3,286,000            
Investments, fair value $ 3,271,000 $ 3,307,000            
Investment, Identifier [Axis]: ImageOne Industries, LLC Common A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ImageOneIndustriesLLCMember whfcl:ImageOneIndustriesLLCMember            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonAUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonAUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Acquisition Date Sep. 20, 2019 Sep. 20, 2019            
Investment owned shares | shares 238   238 238 238      
Principal/Share Amount   $ 235,000            
Investments, amortized cost $ 13,000 10,000            
Investments, fair value   $ 12,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ImpactAdvisorsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Technology   Health Care Technology Health Care Technology Health Care Technology      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.50%   4.50% 4.50% 4.50%      
Interest Rate 8.17%   8.17% 8.17% 8.17%      
Acquisition Date May 01, 2025              
Maturity Date Mar. 21, 2031   Mar. 21, 2031 Mar. 21, 2031 Mar. 21, 2031      
Investments, fair value $ 10,000              
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ImpactAdvisorsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Technology   Health Care Technology Health Care Technology Health Care Technology      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.50%   4.50% 4.50% 4.50%      
Interest Rate 8.17%   8.17% 8.17% 8.17%      
Acquisition Date May 01, 2025              
Maturity Date Mar. 21, 2031   Mar. 21, 2031 Mar. 21, 2031 Mar. 21, 2031      
Investments, fair value $ 4,000              
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ImpactAdvisorsLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Technology   Health Care Technology Health Care Technology Health Care Technology      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.50%   4.50% 4.50% 4.50%      
Interest Rate 8.17%   8.17% 8.17% 8.17%      
Acquisition Date May 01, 2025              
Maturity Date Mar. 21, 2031   Mar. 21, 2031 Mar. 21, 2031 Mar. 21, 2031      
Principal/Share Amount $ 4,169,000              
Investments, amortized cost 4,132,000              
Investments, fair value $ 4,169,000              
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Infotree Holdco LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Human Resource & Employment Services   Human Resource & Employment Services Human Resource & Employment Services Human Resource & Employment Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.42%   9.42% 9.42% 9.42%      
Acquisition Date Feb. 19, 2025              
Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030      
Investments, fair value $ 2,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Revolving Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] Infotree Holdco LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Human Resource & Employment Services   Human Resource & Employment Services Human Resource & Employment Services Human Resource & Employment Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.42%   9.42% 9.42% 9.42%      
Acquisition Date Mar. 24, 2025              
Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030      
Investments, fair value $ 1,000              
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Infotree Holdco LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Human Resource & Employment Services   Human Resource & Employment Services Human Resource & Employment Services Human Resource & Employment Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.42%   9.42% 9.42% 9.42%      
Acquisition Date Feb. 19, 2025              
Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030      
Principal/Share Amount $ 2,947,000              
Investments, amortized cost 2,899,000              
Investments, fair value $ 2,907,000              
Percent of net assets 1.10%   1.10% 1.10% 1.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] Infotree Holdco LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Human Resource & Employment Services   Human Resource & Employment Services Human Resource & Employment Services Human Resource & Employment Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.42%   9.42% 9.42% 9.42%      
Acquisition Date Mar. 24, 2025              
Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030      
Principal/Share Amount $ 2,526,000              
Investments, amortized cost 2,484,000              
Investments, fair value $ 2,492,000              
Investment, Identifier [Axis]: JVMC Holdings Corp First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:ZephyrBuyerL.p.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Interactive Media & Services         Interactive Media & Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.83%         10.83%  
Acquisition Date   Jan. 31, 2024            
Maturity Date   Jan. 31, 2030         Jan. 31, 2030  
Principal/Share Amount   $ 14,087,000            
Investments, amortized cost   13,789,000            
Investments, fair value   $ 14,166,000            
Percent of net assets   5.00%         5.00%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:JuniperLandscapingHoldingsLLCMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services   Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.56%   9.56% 9.56% 9.56%      
Acquisition Date May 23, 2025              
Maturity Date Dec. 29, 2027   Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027      
Principal/Share Amount $ 890,000              
Investments, amortized cost 884,000              
Investments, fair value $ 910,000              
Percent of net assets 0.40%   0.40% 0.40% 0.40%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 6.25% 5.75% 5.75% 5.75%   6.25%  
Interest Rate 9.43% 10.85% 9.43% 9.43% 9.43%   10.85%  
Acquisition Date Mar. 01, 2022 Mar. 01, 2022            
Maturity Date Dec. 29, 2027 Dec. 29, 2026 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027   Dec. 29, 2026  
Principal/Share Amount $ 2,319,000 $ 2,343,000            
Investments, amortized cost 2,309,000 2,326,000            
Investments, fair value $ 2,319,000 $ 2,343,000            
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:JuniperLandscapingHoldingsLLCMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services   Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.51%   9.51% 9.51% 9.51%      
Acquisition Date May 23, 2025              
Maturity Date Dec. 29, 2027   Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027      
Principal/Share Amount $ 238,000              
Investments, amortized cost 235,000              
Investments, fair value $ 246,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 6.25% 5.75% 5.75% 5.75%   6.25%  
Interest Rate 9.52% 10.82% 9.52% 9.52% 9.52%   10.82%  
Acquisition Date Mar. 01, 2022 Mar. 01, 2022            
Maturity Date Dec. 29, 2027 Dec. 29, 2026 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027   Dec. 29, 2026  
Principal/Share Amount $ 310,000 $ 517,000            
Investments, amortized cost 309,000 513,000            
Investments, fair value $ 314,000 $ 522,000            
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:JuniperLandscapingHoldingsLLCMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services   Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.43%   9.43% 9.43% 9.43%      
Acquisition Date May 23, 2025              
Maturity Date Dec. 29, 2027   Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027      
Principal/Share Amount $ 454,000              
Investments, amortized cost 449,000              
Investments, fair value $ 454,000              
Percent of net assets 0.20%   0.20% 0.20% 0.20%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 6.25% 5.75% 5.75% 5.75%   6.25%  
Interest Rate 9.43% 10.84% 9.43% 9.43% 9.43%   10.84%  
Acquisition Date Mar. 01, 2022 Mar. 01, 2022            
Maturity Date Dec. 29, 2027 Dec. 29, 2026 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027   Dec. 29, 2026  
Principal/Share Amount $ 10,964,000 $ 11,078,000            
Investments, amortized cost 10,917,000 11,000,000            
Investments, fair value $ 10,964,000 $ 11,078,000            
Investment, Identifier [Axis]: KORE Wireless Group Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Wireless Telecommunication Services Wireless Telecommunication Services Wireless Telecommunication Services Wireless Telecommunication Services Wireless Telecommunication Services   Wireless Telecommunication Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.38% 11.02% 10.38% 10.38% 10.38%   11.02%  
Acquisition Date Nov. 27, 2023 Nov. 27, 2023            
Maturity Date Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028   Nov. 09, 2028  
Investments, fair value $ 10,000 $ 9,000            
Investment, Identifier [Axis]: KORE Wireless Group Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Wireless Telecommunication Services Wireless Telecommunication Services Wireless Telecommunication Services Wireless Telecommunication Services Wireless Telecommunication Services   Wireless Telecommunication Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.38% 11.02% 10.38% 10.38% 10.38%   11.02%  
Acquisition Date Nov. 27, 2023 Nov. 27, 2023            
Maturity Date Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028   Nov. 09, 2028  
Principal/Share Amount $ 6,290,000 $ 6,354,000            
Investments, amortized cost 6,218,000 6,256,000            
Investments, fair value $ 6,290,000 $ 6,323,000            
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   Kelso Industries L L C [Member]            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Construction & Engineering         Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.09%         10.09%  
Acquisition Date   Dec. 26, 2024            
Maturity Date   Dec. 31, 2029         Dec. 31, 2029  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Kelso Industries L L C [Member] Kelso Industries L L C [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.57% 10.09% 9.57% 9.57% 9.57%   10.09%  
Acquisition Date Dec. 26, 2024 Dec. 26, 2024            
Maturity Date Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029   Dec. 31, 2029  
Principal/Share Amount $ 4,785,000 $ 3,611,000            
Investments, amortized cost 4,710,000 3,539,000            
Investments, fair value $ 4,823,000 $ 3,539,000            
Percent of net assets 1.90% 1.20% 1.90% 1.90% 1.90%   1.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Keras Holdings, LLC Shares                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:KerasHoldingsLLCMember whfcl:KerasHoldingsLLCMember            
Investment, Type [Extensible Enumeration] Common Stock [Member] whfcl:SharesMember Common Stock [Member] Common Stock [Member] Common Stock [Member]   whfcl:SharesMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Acquisition Date Dec. 31, 2020 Dec. 31, 2020            
Investment owned shares | shares 496   496 496 496      
Principal/Share Amount   $ 496,000            
Investments, amortized cost $ 496,000 496,000            
Investments, fair value $ 446,000 $ 779,000            
Percent of net assets 0.20% 0.30% 0.20% 0.20% 0.20%   0.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: LINC Systems, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:LINCSystemsLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Packaged Foods & Meats         Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   8.50%         8.50%  
Interest Rate   12.99%         12.99%  
Acquisition Date   Jun. 22, 2021            
Maturity Date   Feb. 24, 2026         Feb. 24, 2026  
Investments, fair value   $ 3,000            
Investment, Identifier [Axis]: LINC Systems, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:LINCSystemsLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Paper & Plastic Packaging Products & Materials         Paper & Plastic Packaging Products & Materials  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   8.50%         8.50%  
Interest Rate   12.99%         12.99%  
Acquisition Date   Jun. 22, 2021            
Maturity Date   Feb. 24, 2026         Feb. 24, 2026  
Principal/Share Amount   $ 8,155,000            
Investments, amortized cost   8,114,000            
Investments, fair value   $ 8,155,000            
Investment, Identifier [Axis]: LINC Systems, LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:LINCSystemsLLCMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Paper & Plastic Packaging Products & Materials   Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member]   Base Rate [Member] Base Rate [Member] Base Rate [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.25%   6.25% 6.25% 6.25%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Jun. 22, 2021              
Maturity Date Feb. 24, 2026   Feb. 24, 2026 Feb. 24, 2026 Feb. 24, 2026      
Investment, Identifier [Axis]: LINC Systems, LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:LINCSystemsLLCMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Paper & Plastic Packaging Products & Materials   Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member]   Base Rate [Member] Base Rate [Member] Base Rate [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.25%   6.25% 6.25% 6.25%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Jun. 22, 2021              
Maturity Date Feb. 24, 2026   Feb. 24, 2026 Feb. 24, 2026 Feb. 24, 2026      
Principal/Share Amount $ 7,900,000              
Investments, amortized cost 7,895,000              
Investments, fair value $ 7,900,000              
Investment, Identifier [Axis]: LSCS Holdings, Inc. Second Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:LSCSHoldingsIncMember            
Investment, Type [Extensible Enumeration]   whfcl:SecondLienSecuredTermLoanMember         whfcl:SecondLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Life Sciences Tools & Services         Life Sciences Tools & Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   0.50%         0.50%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.47%         12.47%  
Acquisition Date   Nov. 23, 2021            
Maturity Date   Dec. 16, 2029         Dec. 16, 2029  
Principal/Share Amount   $ 5,000,000            
Investments, amortized cost   4,953,000            
Investments, fair value   $ 5,000,000            
Percent of net assets   1.70%         1.70%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:LabLogisticsLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Services         Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   7.25%         7.25%  
Interest Rate   11.71%         11.71%  
Acquisition Date   Oct. 16, 2019            
Maturity Date   Dec. 31, 2025         Dec. 31, 2025  
Principal/Share Amount   $ 5,020,000            
Investments, amortized cost   5,020,000            
Investments, fair value   $ 5,020,000            
Percent of net assets   1.80%         1.80%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:LabLogisticsLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Services         Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   7.25%         7.25%  
Interest Rate   11.71%         11.71%  
Acquisition Date   Sep. 17, 2024            
Maturity Date   Dec. 31, 2025         Dec. 31, 2025  
Principal/Share Amount   $ 437,000            
Investments, amortized cost   437,000            
Investments, fair value   $ 437,000            
Percent of net assets   0.20%         0.20%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:LabLogisticsLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Services         Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   7.25%         7.25%  
Interest Rate   11.71%         11.71%  
Acquisition Date   Oct. 16, 2019            
Maturity Date   Dec. 31, 2025         Dec. 31, 2025  
Principal/Share Amount   $ 5,383,000            
Investments, amortized cost   5,381,000            
Investments, fair value   $ 5,383,000            
Percent of net assets   1.90%         1.90%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.50% 1.50% 1.50% 1.50% 1.50%   1.50%  
Spread Above Index 6.00% 7.50% 6.00% 6.00% 6.00%   7.50%  
Interest Rate 9.67% 11.98% 9.67% 9.67% 9.67%   11.98%  
Acquisition Date Dec. 27, 2022 Dec. 27, 2022            
Maturity Date Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027   Dec. 27, 2027  
Investments, fair value $ 4,000 $ 10,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.50% 1.50% 1.50% 1.50% 1.50%   1.50%  
Spread Above Index 6.00% 7.50% 6.00% 6.00% 6.00%   7.50%  
Interest Rate 9.67% 11.98% 9.67% 9.67% 9.67%   11.98%  
Acquisition Date Dec. 27, 2022 Dec. 27, 2022            
Maturity Date Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027   Dec. 27, 2027  
Principal/Share Amount $ 13,645,000 $ 13,211,000            
Investments, amortized cost 13,486,000 12,981,000            
Investments, fair value $ 13,584,000 $ 13,312,000            
Percent of net assets 5.20% 4.60% 5.20% 5.20% 5.20%   4.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan A                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredTermLoanAMember whfcl:FirstLienSecuredTermLoanAMember whfcl:FirstLienSecuredTermLoanAMember whfcl:FirstLienSecuredTermLoanAMember whfcl:FirstLienSecuredTermLoanAMember   whfcl:FirstLienSecuredTermLoanAMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 7.50% 7.50% 7.50% 7.50%   7.50%  
Interest Rate 11.32% 11.96% 11.32% 11.32% 11.32%   11.96%  
Acquisition Date Jun. 29, 2020 Jun. 29, 2020            
Maturity Date Sep. 30, 2026 Jun. 29, 2025 Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026   Jun. 29, 2025  
Principal/Share Amount $ 5,120,000 $ 5,461,000            
Investments, amortized cost 5,119,000 5,453,000            
Investments, fair value $ 5,120,000 $ 5,461,000            
Percent of net assets 2.00% 1.90% 2.00% 2.00% 2.00%   1.90%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan B                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredTermLoanBMember whfcl:FirstLienSecuredTermLoanBMember whfcl:FirstLienSecuredTermLoanBMember whfcl:FirstLienSecuredTermLoanBMember whfcl:FirstLienSecuredTermLoanBMember   whfcl:FirstLienSecuredTermLoanBMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Spread Above Index 9.50% 9.50% 9.50% 9.50% 9.50%   9.50%  
PIK interest rate 9.50% 9.50% 9.50% 9.50% 9.50%   9.50%  
Acquisition Date Jun. 29, 2020 Jun. 29, 2020            
Maturity Date Sep. 30, 2026 Jun. 29, 2025 Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026   Jun. 29, 2025  
Principal/Share Amount $ 1,753,000 $ 1,594,000            
Investments, amortized cost 1,752,000 1,592,000            
Investments, fair value $ 1,753,000 $ 1,594,000            
Percent of net assets 0.70% 0.60% 0.70% 0.70% 0.70%   0.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: LogicMonitor, Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:LogicmonitorInc.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Systems Software         Systems Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   0.75%         0.75%  
Spread Above Index   5.50%         5.50%  
Interest Rate   9.99%         9.99%  
Acquisition Date   Nov. 19, 2024            
Maturity Date   Nov. 19, 2031         Nov. 19, 2031  
Principal/Share Amount   $ 6,220,000            
Investments, amortized cost   6,144,000            
Investments, fair value   $ 6,144,000            
Percent of net assets   2.10%         2.10%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:LogicmonitorInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Systems Software   Systems Software Systems Software Systems Software      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.34%   9.34% 9.34% 9.34%      
Acquisition Date Dec. 02, 2025              
Maturity Date Nov. 19, 2031   Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Spread Above Index 5.50% 5.50% 5.50% 5.50% 5.50%   5.50%  
Interest Rate 9.34% 9.99% 9.34% 9.34% 9.34%   9.99%  
Acquisition Date Nov. 19, 2024 Nov. 19, 2024            
Maturity Date Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031   Nov. 19, 2031  
Investments, fair value $ 5,000              
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:LogicmonitorInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Systems Software   Systems Software Systems Software Systems Software      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.34%   9.34% 9.34% 9.34%      
Acquisition Date Nov. 19, 2024              
Maturity Date Nov. 19, 2031   Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031      
Principal/Share Amount $ 8,220,000              
Investments, amortized cost 8,130,000              
Investments, fair value $ 8,186,000              
Percent of net assets 3.20%   3.20% 3.20% 3.20%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Luxury Brand Holdings, Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:LuxuryBrandHoldingsIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Broadline Retail         Broadline Retail  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.11%         10.11%  
Acquisition Date   Dec. 04, 2020            
Maturity Date   Jun. 04, 2026         Jun. 04, 2026  
Principal/Share Amount   $ 4,580,000            
Investments, amortized cost   4,556,000            
Investments, fair value   $ 4,580,000            
Percent of net assets   1.60%         1.60%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: M2S Group Intermediate Holdings, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:M2sGroupIntermediateHoldingsIncMember whfcl:M2sGroupIntermediateHoldingsIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Paper Products Paper Products Paper Products Paper Products Paper Products   Paper Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Base Rate [Member]  
Floor 0.50% 0.50% 0.50% 0.50% 0.50%   0.50%  
Spread Above Index 4.75% 4.73% 4.75% 4.75% 4.75%   4.73%  
Interest Rate 8.59% 9.10% 8.59% 8.59% 8.59%   9.10%  
Acquisition Date Aug. 22, 2024 Aug. 22, 2024            
Maturity Date Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031   Aug. 25, 2031  
Principal/Share Amount $ 9,368,000 $ 9,770,000            
Investments, amortized cost 8,838,000 9,119,000            
Investments, fair value $ 9,276,000 $ 9,453,000            
Percent of net assets 3.60% 3.30% 3.60% 3.60% 3.60%   3.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: MBS Highway, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MbsHighwayLlcMember whfcl:MbsHighwayLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Application Software Application Software Application Software Application Software Application Software   Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 8.00% 8.50% 8.00% 8.00% 8.00%   8.50%  
Interest Rate 12.03% 13.20% 12.03% 12.03% 12.03%   13.20%  
Cash interest rate   12.70%         12.70%  
PIK interest rate   0.50%         0.50%  
Acquisition Date Oct. 13, 2022 Oct. 13, 2022            
Maturity Date Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027   Oct. 13, 2027  
Principal/Share Amount $ 9,204,000 $ 9,286,000            
Investments, amortized cost 9,122,000 9,157,000            
Investments, fair value $ 9,184,000 $ 9,212,000            
Percent of net assets 3.50% 3.20% 3.50% 3.50% 3.50%   3.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: MGT Merger Target, LLC (d/b/a MGT Consulting Group), First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] MGT Merger Target, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.74%   8.74% 8.74% 8.74%      
Acquisition Date Apr. 08, 2025              
Maturity Date Apr. 10, 2029   Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029      
Principal/Share Amount $ 283,000              
Investments, amortized cost 281,000              
Investments, fair value $ 300,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] MGT Merger Target, LLC [Member] MGT Merger Target, LLC [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.00% 5.97% 5.00% 5.00% 5.00%   5.97%  
Interest Rate 8.72% 10.51% 8.72% 8.72% 8.72%   10.51%  
Acquisition Date May 10, 2023 May 10, 2023            
Maturity Date Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029   Apr. 10, 2029  
Principal/Share Amount $ 1,322,000 $ 821,000            
Investments, amortized cost 1,300,000 804,000            
Investments, fair value $ 1,322,000 $ 817,000            
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   MGT Merger Target, LLC [Member]            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   IT Consulting And Other Services         IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Prime Rate [Member]         Prime Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.50%         5.50%  
Interest Rate   13.00%         13.00%  
Acquisition Date   May 10, 2023            
Maturity Date   Apr. 10, 2028         Apr. 10, 2028  
Principal/Share Amount   $ 241,000            
Investments, amortized cost   236,000            
Investments, fair value   $ 249,000            
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   MGT Merger Target, LLC [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   IT Consulting And Other Services         IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.39%         6.39%  
Interest Rate   10.85%         10.85%  
Acquisition Date   May 10, 2023            
Maturity Date   Apr. 10, 2029         Apr. 10, 2029  
Principal/Share Amount   $ 7,187,000            
Investments, amortized cost   7,040,000            
Investments, fair value   $ 7,176,000            
Investment, Identifier [Axis]: MGT Merger Target, LLC First lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] MGT Merger Target, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Prime Rate [Member]   Prime Rate [Member] Prime Rate [Member] Prime Rate [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.00%   4.00% 4.00% 4.00%      
Interest Rate 10.75%   10.75% 10.75% 10.75%      
Acquisition Date Apr. 07, 2025              
Maturity Date Apr. 10, 2028   Apr. 10, 2028 Apr. 10, 2028 Apr. 10, 2028      
Principal/Share Amount $ 714,000              
Investments, amortized cost 705,000              
Investments, fair value $ 715,000              
Investment, Identifier [Axis]: MGT Merger Target, LLC First lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] MGT Merger Target, LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.72%   8.72% 8.72% 8.72%      
Acquisition Date May 10, 2023              
Maturity Date Apr. 10, 2029   Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029      
Principal/Share Amount $ 8,555,000              
Investments, amortized cost 8,430,000              
Investments, fair value $ 8,567,000              
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:MSIInformationServicesIncMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Education Services         Education Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Base Rate [Member]         Base Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   8.82%         8.82%  
PIK interest rate   16.11%         16.11%  
Acquisition Date   Apr. 25, 2022            
Maturity Date   Apr. 24, 2026         Apr. 24, 2026  
Principal/Share Amount   $ 1,050,000            
Investments, amortized cost   1,043,000            
Investments, fair value   $ 945,000            
Percent of net assets   0.30%         0.30%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:MSIInformationServicesIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Education Services         Education Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   9.75%         9.75%  
PIK interest rate   14.23%         14.23%  
Acquisition Date   Apr. 25, 2022            
Maturity Date   Apr. 24, 2026         Apr. 24, 2026  
Principal/Share Amount   $ 8,746,000            
Investments, amortized cost   8,552,000            
Investments, fair value   $ 7,871,000            
Percent of net assets   2.80%         2.80%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] M&M OpCo. LLC (d/b/a Escalent, Inc.) M&M OpCo. LLC (d/b/a Escalent, Inc.)            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Research & Consulting Services Research & Consulting Services Research & Consulting Services Research & Consulting Services Research & Consulting Services   Research & Consulting Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.00% 8.00% 6.00% 6.00% 6.00%   8.00%  
Interest Rate 9.67% 12.43% 9.67% 9.67% 9.67%   12.43%  
Acquisition Date Apr. 07, 2023 Apr. 07, 2023            
Maturity Date Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029   Apr. 09, 2029  
Investments, fair value $ 4,000 $ 5,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] M&M OpCo. LLC (d/b/a Escalent, Inc.) M&M OpCo. LLC (d/b/a Escalent, Inc.)            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Research & Consulting Services Research & Consulting Services Research & Consulting Services Research & Consulting Services Research & Consulting Services   Research & Consulting Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.00% 8.00% 6.00% 6.00% 6.00%   8.00%  
Interest Rate 9.67% 12.43% 9.67% 9.67% 9.67%   12.43%  
Acquisition Date Apr. 07, 2023 Apr. 07, 2023            
Maturity Date Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029   Apr. 09, 2029  
Principal/Share Amount $ 4,827,000 $ 4,927,000            
Investments, amortized cost 4,748,000 4,823,000            
Investments, fair value $ 4,827,000 $ 4,922,000            
Percent of net assets 1.90% 1.70% 1.90% 1.90% 1.90%   1.70%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MarkiMicrowaveLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] whfcl:ElectronicEquipmentAndInstrumentsMember   whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.25%   4.25% 4.25% 4.25%      
Interest Rate 8.12%   8.12% 8.12% 8.12%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 21, 2031   Nov. 21, 2031 Nov. 21, 2031 Nov. 21, 2031      
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MarkiMicrowaveLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] whfcl:ElectronicEquipmentAndInstrumentsMember   whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.25%   4.25% 4.25% 4.25%      
Interest Rate 8.12%   8.12% 8.12% 8.12%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 21, 2031   Nov. 21, 2031 Nov. 21, 2031 Nov. 21, 2031      
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MarkiMicrowaveLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] whfcl:ElectronicEquipmentAndInstrumentsMember   whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.25%   4.25% 4.25% 4.25%      
Interest Rate 8.12%   8.12% 8.12% 8.12%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 21, 2031   Nov. 21, 2031 Nov. 21, 2031 Nov. 21, 2031      
Principal/Share Amount $ 6,045,000              
Investments, amortized cost 5,986,000              
Investments, fair value $ 5,985,000              
Investment, Identifier [Axis]: Marlin DTC-LS Midco 2, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MarlinDTC-LSMidco2LLCMember whfcl:MarlinDTC-LSMidco2LLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Broadline Retail Broadline Retail Broadline Retail Broadline Retail Broadline Retail   Broadline Retail  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.32% 11.03% 10.32% 10.32% 10.32%   11.03%  
Acquisition Date Jul. 19, 2019 Jul. 19, 2019            
Maturity Date Jul. 01, 2026 Jul. 01, 2025 Jul. 01, 2026 Jul. 01, 2026 Jul. 01, 2026   Jul. 01, 2025  
Investments, fair value $ (39,000) $ (38,000)            
Investment, Identifier [Axis]: Marlin DTC-LS Midco 2, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MarlinDTC-LSMidco2LLCMember whfcl:MarlinDTC-LSMidco2LLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Broadline Retail Broadline Retail Broadline Retail Broadline Retail Broadline Retail   Broadline Retail  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.32% 11.03% 10.32% 10.32% 10.32%   11.03%  
Acquisition Date Jul. 19, 2019 Jul. 19, 2019            
Maturity Date Jul. 01, 2026 Jul. 01, 2025 Jul. 01, 2026 Jul. 01, 2026 Jul. 01, 2026   Jul. 01, 2025  
Principal/Share Amount $ 18,019,000 $ 18,613,000            
Investments, amortized cost 18,019,000 18,577,000            
Investments, fair value $ 17,299,000 $ 17,865,000            
Investment, Identifier [Axis]: Max Solutions Inc. Common Stock                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember            
Investment, Type [Extensible Enumeration] Common Stock [Member] Common Stock [Member] Common Stock [Member] Common Stock [Member] Common Stock [Member]   Common Stock [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Paper & Plastic Packaging Products & Materials Leisure Products Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials   Leisure Products  
Acquisition Date Sep. 29, 2022 Sep. 29, 2022            
Investment owned shares | shares 4   4 4 4      
Principal/Share Amount   $ 4,000            
Investments, amortized cost $ 400,000 $ 400,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:MaxSolutionsIncMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Packaged Foods & Meats         Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   8.10%         8.10%  
Interest Rate   12.56%         12.56%  
Acquisition Date   Oct. 07, 2022            
Maturity Date   Sep. 29, 2028         Sep. 29, 2028  
Principal/Share Amount   $ 414,000            
Investments, amortized cost   411,000            
Investments, fair value   $ 402,000            
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:MaxSolutionsIncMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Packaged Foods & Meats         Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:CanadianOvernightRepoRateAverageMember         whfcl:CanadianOvernightRepoRateAverageMember  
Floor   1.00%         1.00%  
Spread Above Index   8.10%         8.10%  
Interest Rate   12.56%         12.56%  
Acquisition Date   Oct. 07, 2022            
Maturity Date   Sep. 29, 2028         Sep. 29, 2028  
Investments, fair value   $ (3,000)            
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:MaxSolutionsIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Packaged Foods & Meats         Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   8.11%         8.11%  
Interest Rate   12.57%         12.57%  
Acquisition Date   Oct. 07, 2022            
Maturity Date   Sep. 29, 2028         Sep. 29, 2028  
Principal/Share Amount   $ 6,521,000            
Investments, amortized cost   6,439,000            
Investments, fair value   $ 6,324,000            
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxSolutionsIncMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Paper & Plastic Packaging Products & Materials   Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.90%   6.90% 6.90% 6.90%      
Interest Rate 10.89%   10.89% 10.89% 10.89%      
Acquisition Date Oct. 07, 2022              
Maturity Date Sep. 29, 2028   Sep. 29, 2028 Sep. 29, 2028 Sep. 29, 2028      
Principal/Share Amount $ 410,000              
Investments, amortized cost 407,000              
Investments, fair value $ 408,000              
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxSolutionsIncMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Paper & Plastic Packaging Products & Materials   Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials      
Investment, Variable Interest Rate, Type [Extensible Enumeration] whfcl:CanadianOvernightRepoRateAverageMember   whfcl:CanadianOvernightRepoRateAverageMember whfcl:CanadianOvernightRepoRateAverageMember whfcl:CanadianOvernightRepoRateAverageMember      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.90%   6.90% 6.90% 6.90%      
Interest Rate 10.89%   10.89% 10.89% 10.89%      
Acquisition Date Oct. 07, 2022              
Maturity Date Sep. 29, 2028   Sep. 29, 2028 Sep. 29, 2028 Sep. 29, 2028      
Investments, fair value $ 1,000              
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxSolutionsIncMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Paper & Plastic Packaging Products & Materials   Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials Paper & Plastic Packaging Products & Materials      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.91%   6.91% 6.91% 6.91%      
Interest Rate 10.90%   10.90% 10.90% 10.90%      
Acquisition Date Oct. 07, 2022              
Maturity Date Sep. 29, 2028   Sep. 29, 2028 Sep. 29, 2028 Sep. 29, 2028      
Principal/Share Amount $ 6,451,000              
Investments, amortized cost 6,392,000              
Investments, fair value $ 6,420,000              
Investment, Identifier [Axis]: Maxor Acquisition, Inc. (d/b/a Maxor National Pharmacy Services, LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxorAcquisitionInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Services   Health Care Services Health Care Services Health Care Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.82%   9.82% 9.82% 9.82%      
Acquisition Date Dec. 27, 2024              
Maturity Date Mar. 01, 2029   Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029      
Principal/Share Amount $ 938,000              
Investments, amortized cost 930,000              
Investments, fair value $ 942,000              
Percent of net assets 0.40%   0.40% 0.40% 0.40%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:MaxorAcquisitionInc.Member            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Services         Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.00%         6.00%  
Interest Rate   10.46%         10.46%  
Acquisition Date   Dec. 27, 2024            
Maturity Date   Mar. 01, 2029         Mar. 01, 2029  
Principal/Share Amount   $ 947,000            
Investments, amortized cost   938,000            
Investments, fair value   $ 938,000            
Percent of net assets   0.30%         0.30%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxorAcquisitionInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Health Care Services   Health Care Services Health Care Services Health Care Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.82%   9.82% 9.82% 9.82%      
Acquisition Date Apr. 11, 2023              
Maturity Date Mar. 01, 2029   Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029      
Investments, fair value $ 8,000              
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:MaxorAcquisitionInc.Member whfcl:MaxorAcquisitionInc.Member            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Health Care Services Health Care Services Health Care Services Health Care Services Health Care Services   Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.00% 6.00% 6.00% 6.00% 6.00%   6.00%  
Interest Rate 9.82% 10.46% 9.82% 9.82% 9.82%   10.46%  
Acquisition Date Apr. 11, 2023 Apr. 11, 2023            
Maturity Date Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029   Mar. 01, 2029  
Principal/Share Amount $ 4,951,000 $ 5,002,000            
Investments, amortized cost 4,872,000 4,898,000            
Investments, fair value $ 4,974,000 $ 4,986,000            
Investment, Identifier [Axis]: Maxor Acquisition, Inc.First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:MaxorAcquisitionInc.Member            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Services         Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.00%         6.00%  
Interest Rate   10.46%         10.46%  
Acquisition Date   Apr. 11, 2023            
Maturity Date   Mar. 01, 2029         Mar. 01, 2029  
Investments, fair value   $ 9,000            
Investment, Identifier [Axis]: Media Source, LLC (d/b/a Media Source Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Media Source, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Education Services   Education Services Education Services Education Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.54%   9.54% 9.54% 9.54%      
Cash interest rate 4.77%   4.77% 4.77% 4.77%      
PIK interest rate 4.77%   4.77% 4.77% 4.77%      
Acquisition Date Sep. 01, 2025              
Maturity Date Aug. 30, 2030   Aug. 30, 2030 Aug. 30, 2030 Aug. 30, 2030      
Investments, fair value $ 17,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Media Source, LLC (d/b/a Media Source Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Media Source, LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Education Services   Education Services Education Services Education Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.54%   9.54% 9.54% 9.54%      
Cash interest rate 4.77%   4.77% 4.77% 4.77%      
PIK interest rate 4.77%   4.77% 4.77% 4.77%      
Acquisition Date Sep. 01, 2025              
Maturity Date Aug. 30, 2030   Aug. 30, 2030 Aug. 30, 2030 Aug. 30, 2030      
Principal/Share Amount $ 4,242,000              
Investments, amortized cost 4,242,000              
Investments, fair value $ 4,242,000              
Percent of net assets 1.60%   1.60% 1.60% 1.60%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Medical Device Inc First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:MedicalDeviceIncMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Supplies         Health Care Supplies  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.25%         1.25%  
Spread Above Index   6.25%         6.25%  
Interest Rate   10.68%         10.68%  
Acquisition Date   Jul. 27, 2023            
Maturity Date   Jul. 11, 2029         Jul. 11, 2029  
Investments, fair value   $ 6,000            
Investment, Identifier [Axis]: Medical Device Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:MedicalDeviceIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Health Care Supplies         Health Care Supplies  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.25%         1.25%  
Spread Above Index   6.25%         6.25%  
Interest Rate   10.68%         10.68%  
Acquisition Date   Jul. 27, 2023            
Maturity Date   Jul. 11, 2029         Jul. 11, 2029  
Principal/Share Amount   $ 2,633,000            
Investments, amortized cost   2,584,000            
Investments, fair value   $ 2,660,000            
Investment, Identifier [Axis]: Merriman Holdings LP (d/b/a Escalent, Inc.) Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MerrimanHoldingsLPMember whfcl:MerrimanHoldingsLPMember            
Investment, Type [Extensible Enumeration] whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Research & Consulting Services Research & Consulting Services Research & Consulting Services Research & Consulting Services Research & Consulting Services   Research & Consulting Services  
Acquisition Date Apr. 07, 2023 Apr. 07, 2023            
Investment owned shares | shares 327   327 327 327      
Principal/Share Amount   $ 327,000            
Investments, amortized cost $ 333,000 333            
Investments, fair value $ 312,000 $ 368,000            
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10%   0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals   Pharmaceuticals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 0.75% 1.00% 0.75% 0.75% 0.75%   1.00%  
Spread Above Index 5.25% 6.00% 5.25% 5.25% 5.25%   6.00%  
Interest Rate 8.94% 10.51% 8.94% 8.94% 8.94%   10.51%  
Acquisition Date Dec. 22, 2025 Dec. 16, 2021            
Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031   Nov. 01, 2027  
Principal/Share Amount   $ 874,000            
Investments, amortized cost   865,000            
Investments, fair value   $ 874,000            
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals   Pharmaceuticals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 0.75% 1.00% 0.75% 0.75% 0.75%   1.00%  
Spread Above Index 5.25% 6.00% 5.25% 5.25% 5.25%   6.00%  
Interest Rate 8.94% 10.44% 8.94% 8.94% 8.94%   10.44%  
Acquisition Date Dec. 22, 2025 Dec. 16, 2021            
Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031   Nov. 01, 2027  
Principal/Share Amount   $ 1,156,000            
Investments, amortized cost   1,145,000            
Investments, fair value   $ 1,160,000            
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals   Pharmaceuticals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Euro Interbank Offered Rate Three Month Term [Member] whfcl:EuroInterbankOfferedRateMember Euro Interbank Offered Rate Three Month Term [Member] Euro Interbank Offered Rate Three Month Term [Member] Euro Interbank Offered Rate Three Month Term [Member]   whfcl:EuroInterbankOfferedRateMember  
Floor 0.75% 1.00% 0.75% 0.75% 0.75%   1.00%  
Spread Above Index 5.25% 6.00% 5.25% 5.25% 5.25%   6.00%  
Interest Rate 7.29% 8.85% 7.29% 7.29% 7.29%   8.85%  
Acquisition Date Dec. 22, 2025 Dec. 16, 2021            
Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031   Nov. 01, 2027  
Principal/Share Amount $ 4,621,000 $ 12,039,000            
Investments, amortized cost 5,378,000 13,449,000            
Investments, fair value $ 5,374,000 $ 12,465,000            
Percent of net assets 2.10%   2.10% 2.10% 2.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan Two                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals Pharmaceuticals   Pharmaceuticals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 0.75% 1.00% 0.75% 0.75% 0.75%   1.00%  
Spread Above Index 5.25% 6.00% 5.25% 5.25% 5.25%   6.00%  
Interest Rate 8.94% 10.48% 8.94% 8.94% 8.94%   10.48%  
Acquisition Date Dec. 22, 2025 Dec. 16, 2021            
Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031   Nov. 01, 2027  
Principal/Share Amount $ 6,720,000 $ 962,000            
Investments, amortized cost 6,653,000 952,000            
Investments, fair value $ 6,653,000 $ 962,000            
Percent of net assets 2.60%   2.60% 2.60% 2.60%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Midwest Texas Tea CA, LLC [Member] Midwest Texas Tea CA, LLC [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Distributors Distributors Distributors Distributors Distributors   Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 7.25% 7.50% 7.50% 7.50%   7.25%  
Interest Rate 11.32% 11.71% 11.32% 11.32% 11.32%   11.71%  
Acquisition Date Dec. 22, 2023 Dec. 22, 2023            
Maturity Date Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028   Dec. 22, 2028  
Principal/Share Amount $ 639,000 $ 645,000            
Investments, amortized cost 629,000 632,000            
Investments, fair value $ 639,000 $ 642,000            
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Midwest Texas Tea CA, LLC [Member] Midwest Texas Tea CA, LLC [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Distributors Distributors Distributors Distributors Distributors   Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Base Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Base Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 6.92% 7.50% 7.50% 7.50%   6.92%  
Interest Rate 11.32% 12.39% 11.32% 11.32% 11.32%   12.39%  
Acquisition Date Dec. 22, 2023 Dec. 22, 2023            
Maturity Date Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028   Dec. 22, 2028  
Principal/Share Amount $ 572,000 $ 326,000            
Investments, amortized cost 563,000 319,000            
Investments, fair value $ 572,000 $ 328,000            
Percent of net assets 0.20% 0.10% 0.20% 0.20% 0.20%   0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Midwest Texas Tea CA, LLC [Member] Midwest Texas Tea CA, LLC [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Distributors Distributors Distributors Distributors Distributors   Distributors  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 7.25% 7.50% 7.50% 7.50%   7.25%  
Interest Rate 11.32% 11.71% 11.32% 11.32% 11.32%   11.71%  
Acquisition Date Dec. 22, 2023 Dec. 22, 2023            
Maturity Date Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028   Dec. 22, 2028  
Principal/Share Amount $ 9,188,000 $ 9,443,000            
Investments, amortized cost 9,051,000 9,255,000            
Investments, fair value $ 9,193,000 $ 9,399,000            
Percent of net assets 3.50% 3.30% 3.50% 3.50% 3.50%   3.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]   Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.50% 1.50% 1.50% 1.50% 1.50%   1.50%  
Spread Above Index 7.25% 6.75% 7.25% 7.25% 7.25%   6.75%  
Interest Rate 10.97% 11.16% 10.97% 10.97% 10.97%   11.16%  
Acquisition Date Jan. 10, 2024 Jan. 10, 2024            
Maturity Date Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029   Jan. 10, 2029  
Principal/Share Amount $ 1,579,000 $ 1,596,000            
Investments, amortized cost 1,562,000 1,572,000            
Investments, fair value $ 1,553,000 $ 1,582,000            
Percent of net assets 0.60% 0.60% 0.60% 0.60% 0.60%   0.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]   Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.50% 1.50% 1.50% 1.50% 1.50%   1.50%  
Spread Above Index 7.25% 6.75% 7.25% 7.25% 7.25%   6.75%  
Interest Rate 10.92% 11.08% 10.92% 10.92% 10.92%   11.08%  
Acquisition Date Jan. 10, 2024 Jan. 10, 2024            
Maturity Date Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029   Jan. 10, 2029  
Principal/Share Amount $ 9,212,000 $ 9,306,000            
Investments, amortized cost 9,073,000 9,119,000            
Investments, fair value $ 9,061,000 $ 9,223,000            
Percent of net assets 3.50% 3.20% 3.50% 3.50% 3.50%   3.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Motivational CIV, LLC Class B Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MotivationalCIVLLCMember whfcl:MotivationalCIVLLCMember            
Investment, Type [Extensible Enumeration] whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Acquisition Date Jul. 12, 2021 Jul. 12, 2021            
Investment owned shares | shares 1,250   1,250 1,250 1,250      
Principal/Share Amount   $ 1,250,000            
Investments, amortized cost $ 1,250,000 $ 1,250,000            
Investments, fair value $ 774,000              
Percent of net assets 0.30%   0.30% 0.30% 0.30%      
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 8.50% 6.50% 6.50% 6.50%   8.50%  
Interest Rate 10.48% 13.00% 10.48% 10.48% 10.48%   13.00%  
Cash interest rate   11.00%         11.00%  
PIK interest rate   2.00%         2.00%  
Acquisition Date Jul. 12, 2021 Jul. 12, 2021            
Maturity Date Jul. 12, 2028 Jul. 12, 2026 Jul. 12, 2028 Jul. 12, 2028 Jul. 12, 2028   Jul. 12, 2026  
Principal/Share Amount $ 630,000 $ 1,182,000            
Investments, amortized cost 626,000 1,175,000            
Investments, fair value $ 637,000 $ 1,061,000            
Percent of net assets 0.20% 0.40% 0.20% 0.20% 0.20%   0.40%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.50% 8.50% 6.50% 6.50% 6.50%   8.50%  
Interest Rate 10.37% 12.96% 10.37% 10.37% 10.37%   12.96%  
Cash interest rate   5.48%         5.48%  
PIK interest rate   7.48%         7.48%  
Acquisition Date Jul. 12, 2021 Jul. 12, 2021            
Maturity Date Jul. 12, 2028 Jul. 12, 2026 Jul. 12, 2028 Jul. 12, 2028 Jul. 12, 2028   Jul. 12, 2026  
Principal/Share Amount $ 13,175,000 $ 10,510,000            
Investments, amortized cost 13,104,000 10,449,000            
Investments, fair value $ 13,135,000 $ 9,438,000            
Percent of net assets 5.00% 3.20% 5.00% 5.00% 5.00%   3.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: NM Z Holdco Inc. (d/b/a Zep, Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:NmZHoldcoIncZepIncMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Household Products   Household Products Household Products Household Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.67%   8.67% 8.67% 8.67%      
Acquisition Date Aug. 12, 2025              
Maturity Date Jun. 30, 2031   Jun. 30, 2031 Jun. 30, 2031 Jun. 30, 2031      
Investments, fair value $ 6,000              
Investment, Identifier [Axis]: NM Z Holdco Inc. (d/b/a Zep, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:NmZHoldcoIncZepIncMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Household Products   Household Products Household Products Household Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.67%   8.67% 8.67% 8.67%      
Acquisition Date Aug. 12, 2025              
Maturity Date Jun. 30, 2031   Jun. 30, 2031 Jun. 30, 2031 Jun. 30, 2031      
Principal/Share Amount $ 10,388,000              
Investments, amortized cost 10,293,000              
Investments, fair value $ 10,378,000              
Investment, Identifier [Axis]: NNA Services, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:NNAServicesLLCMember whfcl:NNAServicesLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services   Diversified Support Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 7.25% 6.75% 6.75% 6.75%   7.25%  
Interest Rate 10.57% 11.73% 10.57% 10.57% 10.57%   11.73%  
Acquisition Date Aug. 27, 2021 Aug. 27, 2021            
Maturity Date Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026   Aug. 27, 2026  
Principal/Share Amount $ 8,073,000 $ 9,125,000            
Investments, amortized cost 8,060,000 9,087,000            
Investments, fair value $ 8,037,000 $ 8,941,000            
Percent of net assets 3.10% 3.10% 3.10% 3.10% 3.10%   3.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: NPAV Lessor Corp. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:NPAVLessorCorp.Member            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Real Estate Services [Member]         Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Mar. 01, 2022            
Maturity Date   Jan. 21, 2027         Jan. 21, 2027  
Principal/Share Amount   $ 725,000            
Investments, amortized cost   719,000            
Investments, fair value   $ 660,000            
Investment, Identifier [Axis]: NPAV Lessor Corp. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:NPAVLessorCorp.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Real Estate Services [Member]         Real Estate Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Mar. 01, 2022            
Maturity Date   Jan. 21, 2027         Jan. 21, 2027  
Principal/Share Amount   $ 6,502,000            
Investments, amortized cost   6,448,000            
Investments, fair value   $ 5,918,000            
Investment, Identifier [Axis]: NPAV Lessor Corp., First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:NPAVLessorCorp.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member]   Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Mar. 01, 2022              
Maturity Date Jan. 21, 2027   Jan. 21, 2027 Jan. 21, 2027 Jan. 21, 2027      
Principal/Share Amount $ 725,000              
Investments, amortized cost 722,000              
Investments, fair value $ 660,000              
Investment, Identifier [Axis]: NPAV Lessor Corp., First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:NPAVLessorCorp.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Real Estate Services [Member]   Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member]      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Mar. 01, 2022              
Maturity Date Jan. 21, 2027   Jan. 21, 2027 Jan. 21, 2027 Jan. 21, 2027      
Principal/Share Amount $ 5,517,000              
Investments, amortized cost 5,493,000              
Investments, fair value $ 5,022,000              
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:NavigaIncMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Application Software         Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Base Rate [Member]         Base Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.84%         6.84%  
Interest Rate   12.78%         12.78%  
Acquisition Date   Jun. 14, 2019            
Maturity Date   Jun. 28, 2024         Jun. 28, 2024  
Principal/Share Amount   $ 301,000            
Investments, amortized cost   301,000            
Investments, fair value   $ 169,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:NavigaIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Application Software         Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   7.00%         7.00%  
Interest Rate   12.40%         12.40%  
Acquisition Date   Jun. 14, 2019            
Maturity Date   Jun. 28, 2024         Jun. 28, 2024  
Principal/Share Amount   $ 3,140,000            
Investments, amortized cost   3,140,000            
Investments, fair value   $ 1,763,000            
Percent of net assets   0.60%         0.60%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: New American Crafts Holdings, LLC Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:NewAmericanCraftsHoldingsLlcMember whfcl:NewAmericanCraftsHoldingsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Acquisition Date   Mar. 16, 2023            
Investment owned shares | shares   1         1  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Oil amp; Gas Storage amp; Transportation First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:IslandEnergyServicesLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Oil & Gas Storage & Transportation   Oil & Gas Storage & Transportation Oil & Gas Storage & Transportation Oil & Gas Storage & Transportation      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.50%   0.50% 0.50% 0.50%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.64%   9.64% 9.64% 9.64%      
Acquisition Date Jul. 16, 2025              
Maturity Date Jul. 16, 2032   Jul. 16, 2032 Jul. 16, 2032 Jul. 16, 2032      
Principal/Share Amount $ 10,472,000              
Investments, amortized cost 10,077,000              
Investments, fair value $ 10,158,000              
Percent of net assets 3.90%   3.90% 3.90% 3.90%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Panos Brands, Llc [Member] Panos Brands, Llc [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats   Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.48% 10.15% 9.48% 9.48% 9.48%   10.15%  
Acquisition Date May 14, 2024 Jun. 14, 2024            
Maturity Date May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029   May 14, 2029  
Principal/Share Amount   $ 30,000            
Investments, amortized cost   30,000            
Investments, fair value $ 6,000 $ 36,000            
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Panos Brands, Llc [Member] Panos Brands, Llc [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats   Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.48% 10.15% 9.48% 9.48% 9.48%   10.15%  
Acquisition Date Jun. 14, 2024 May 14, 2024            
Maturity Date May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029   May 14, 2029  
Principal/Share Amount   $ 27,000            
Investments, amortized cost   27,000            
Investments, fair value $ 6,000 $ 33,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   Panos Brands, Llc [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Packaged Foods & Meats         Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.13%         10.13%  
Acquisition Date   Jun. 14, 2024            
Maturity Date   May 14, 2029         May 14, 2029  
Principal/Share Amount   $ 4,520,000            
Investments, amortized cost   4,441,000            
Investments, fair value   $ 4,505,000            
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Panos Brands, Llc [Member] Panos Brands, Llc [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats   Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.48% 10.13% 9.48% 9.48% 9.48%   10.13%  
Acquisition Date Jun. 14, 2024 May 14, 2024            
Maturity Date May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029   May 14, 2029  
Principal/Share Amount $ 4,475,000 $ 4,068,000            
Investments, amortized cost 4,414,000 3,997,000            
Investments, fair value $ 4,475,000 $ 4,054,000            
Percent of net assets   1.40%         1.40%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan, One 05/14/29                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Panos Brands, Llc [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Packaged Foods & Meats   Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.48%   9.48% 9.48% 9.48%      
Acquisition Date May 14, 2024              
Maturity Date May 14, 2029   May 14, 2029 May 14, 2029 May 14, 2029      
Principal/Share Amount $ 4,027,000              
Investments, amortized cost 3,973,000              
Investments, fair value $ 4,027,000              
Percent of net assets 1.60%   1.60% 1.60% 1.60%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: PFB Holdco, Inc Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:PfbHoldingCompanyLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:ClassAUnitsMember         whfcl:ClassAUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Building Products         Building Products  
Acquisition Date   Dec. 17, 2021            
Investment owned shares | shares   1         1  
Investments, amortized cost   $ 24,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: PFB Holding Company, LLC Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:PFBHoldcoIncMember              
Investment, Type [Extensible Enumeration] whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Building Products   Building Products Building Products Building Products      
Acquisition Date Dec. 17, 2021              
Investment owned shares | shares 1   1 1 1      
Investments, amortized cost $ 24,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: PGI Parent LLC (d/b/a Prime Electric, Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:PgiParentLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering   Construction & Engineering Construction & Engineering Construction & Engineering      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.67%   8.67% 8.67% 8.67%      
Acquisition Date Dec. 31, 2025              
Maturity Date Dec. 31, 2031   Dec. 31, 2031 Dec. 31, 2031 Dec. 31, 2031      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: PGI Parent LLC (d/b/a Prime Electric, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:PgiParentLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering   Construction & Engineering Construction & Engineering Construction & Engineering      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.67%   8.67% 8.67% 8.67%      
Acquisition Date Dec. 31, 2025              
Maturity Date Dec. 31, 2031   Dec. 31, 2031 Dec. 31, 2031 Dec. 31, 2031      
Principal/Share Amount $ 5,077,000              
Investments, amortized cost 5,026,000              
Investments, fair value $ 5,026,000              
Percent of net assets 1.90%   1.90% 1.90% 1.90%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:PltfrmCompaniesLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Advertising         Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   3.00%         3.00%  
Spread Above Index   9.00%         9.00%  
Interest Rate   13.34%         13.34%  
Cash interest rate   12.34%         12.34%  
PIK interest rate   1.00%         1.00%  
Acquisition Date   Jan. 29, 2024            
Maturity Date   Jan. 29, 2029         Jan. 29, 2029  
Principal/Share Amount   $ 889,000            
Investments, amortized cost   867,000            
Investments, fair value   $ 916,000            
Percent of net assets   0.30%         0.30%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:PltfrmCompaniesLlcMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Advertising         Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   3.00%         3.00%  
Spread Above Index   9.00%         9.00%  
Interest Rate   13.36%         13.36%  
Cash interest rate   12.36%         12.36%  
PIK interest rate   1.00%         1.00%  
Acquisition Date   Jan. 29, 2024            
Maturity Date   Jan. 29, 2029         Jan. 29, 2029  
Principal/Share Amount   $ 7,950,000            
Investments, amortized cost   7,757,000            
Investments, fair value   $ 8,188,000            
Percent of net assets   3.00%         3.00%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Patagonia Holdco LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:PatagoniaHoldcoLLCMember whfcl:PatagoniaHoldcoLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Integrated Telecommunication Services Integrated Telecommunication Services Integrated Telecommunication Services Integrated Telecommunication Services Integrated Telecommunication Services   Integrated Telecommunication Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 0.50% 0.50% 0.50% 0.50% 0.50%   0.50%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.62% 10.27% 9.62% 9.62% 9.62%   10.27%  
Acquisition Date Aug. 05, 2022 Aug. 05, 2022            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Principal/Share Amount $ 14,150,000 $ 14,296,000            
Investments, amortized cost 12,839,000 12,602,000            
Investments, fair value $ 11,603,000 $ 13,135,000            
Percent of net assets 4.50% 4.60% 4.50% 4.50% 4.50%   4.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Delayed Draw Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:PavementPartnersIntercoLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Construction & Engineering         Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.75%         6.75%  
Interest Rate   11.23%         11.23%  
Acquisition Date   Mar. 17, 2023            
Maturity Date   Feb. 07, 2028         Feb. 07, 2028  
Principal/Share Amount   $ 569,000            
Investments, amortized cost   558,000            
Investments, fair value   $ 569,000            
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Revolving Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:PavementPartnersIntercoLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Construction & Engineering         Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.75%         6.75%  
Interest Rate   11.23%         11.23%  
Acquisition Date   Mar. 17, 2023            
Maturity Date   Feb. 07, 2028         Feb. 07, 2028  
Principal/Share Amount   $ 338,000            
Investments, amortized cost   331,000            
Investments, fair value   $ 341,000            
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:PavementPartnersIntercoLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Construction & Engineering         Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.75%         6.75%  
Interest Rate   11.23%         11.23%  
Acquisition Date   Mar. 17, 2023            
Maturity Date   Feb. 07, 2028         Feb. 07, 2028  
Principal/Share Amount   $ 5,117,000            
Investments, amortized cost   5,015,000            
Investments, fair value   $ 5,111,000            
Investment, Identifier [Axis]: Pirtek Holdco, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services   Diversified Support Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 4.50% 5.50% 4.50% 4.50% 4.50%   5.50%  
Interest Rate 8.20% 9.95% 8.20% 8.20% 8.20%   9.95%  
Acquisition Date Oct. 31, 2023 Oct. 31, 2023            
Maturity Date Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028   Oct. 26, 2028  
Investments, fair value $ 9,000 $ 17,000            
Investment, Identifier [Axis]: Pirtek Holdco, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services   Diversified Support Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 4.50% 5.50% 4.50% 4.50% 4.50%   5.50%  
Interest Rate 8.20% 9.95% 8.20% 8.20% 8.20%   9.95%  
Acquisition Date Oct. 31, 2023 Oct. 31, 2023            
Maturity Date Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028   Oct. 26, 2028  
Principal/Share Amount $ 12,389,000 $ 7,425,000            
Investments, amortized cost 12,284,000 7,298,000            
Investments, fair value $ 12,332,000 $ 7,425,000            
Investment, Identifier [Axis]: Playmonster Group Equity, Inc Common Stock                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember            
Investment, Type [Extensible Enumeration] Common Stock [Member] Common Stock [Member] Common Stock [Member] Common Stock [Member] Common Stock [Member]   Common Stock [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Acquisition Date Jan. 24, 2022 Jan. 24, 2022            
Investment owned shares | shares 72   72 72 72      
Principal/Share Amount   $ 72,000            
Investments, amortized cost $ 460,000 $ 460,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Playmonster Group Equity, Inc. Preferred Stock                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember            
Investment, Type [Extensible Enumeration] us-gaap:PreferredStockMember us-gaap:PreferredStockMember us-gaap:PreferredStockMember us-gaap:PreferredStockMember us-gaap:PreferredStockMember   us-gaap:PreferredStockMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Spread Above Index 14.00% 14.00% 14.00% 14.00% 14.00%   14.00%  
PIK interest rate 14.00% 14.00% 14.00% 14.00% 14.00%   14.00%  
Acquisition Date Jan. 24, 2022 Jan. 24, 2022            
Investment owned shares | shares 36   36 36 36      
Principal/Share Amount   $ 36,000            
Investments, amortized cost $ 3,600,000 $ 3,600,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] true false true true true   false  
Investment, Identifier [Axis]: Playmonster Group LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 9.00% 9.00% 9.00% 9.00% 9.00%   9.00%  
PIK interest rate 12.99% 13.74% 12.99% 12.99% 12.99%   13.74%  
Acquisition Date Jun. 07, 2021 Jun. 07, 2021            
Maturity Date Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026   Jun. 08, 2026  
Principal/Share Amount $ 5,595,000 $ 4,890,000            
Investments, amortized cost 3,661,000 3,661,000            
Investments, fair value $ 1,729,000 $ 1,635,000           1,363,000
Percent of net assets 0.70% 0.60% 0.70% 0.70% 0.70%   0.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Playmonster Group LLC, Priority First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember            
Investment, Type [Extensible Enumeration] whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember   whfcl:PriorityFirstLienSecuredTermLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 6.75% 6.75% 6.75% 6.75%   6.75%  
PIK interest rate 10.74% 11.41% 10.74% 10.74% 10.74%   11.41%  
Acquisition Date Dec. 09, 2022 Dec. 09, 2022            
Maturity Date Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026   Jun. 08, 2026  
Principal/Share Amount $ 1,442,000 $ 1,289,000            
Investments, amortized cost 1,438,000 1,275,000            
Investments, fair value $ 1,355,000 $ 1,172,000           1,015,000
Percent of net assets 0.50% 0.40% 0.50% 0.50% 0.50%   0.40%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:PowerServiceGroupCrAcquisitionIncMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Heavy Electrical Equipment         Heavy Electrical Equipment  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.75%         6.75%  
Interest Rate   11.23%         11.23%  
Acquisition Date   Jul. 11, 2022            
Maturity Date   Jun. 25, 2026         Jun. 25, 2026  
Principal/Share Amount   $ 1,340,000            
Investments, amortized cost   1,329,000            
Investments, fair value   $ 1,354,000            
Percent of net assets   0.50%         0.50%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:PowerServiceGroupCrAcquisitionIncMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Heavy Electrical Equipment         Heavy Electrical Equipment  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.75%         6.75%  
Interest Rate   11.23%         11.23%  
Acquisition Date   Jun. 25, 2021            
Maturity Date   Jun. 25, 2026         Jun. 25, 2026  
Principal/Share Amount   $ 8,697,000            
Investments, amortized cost   8,642,000            
Investments, fair value   $ 8,784,000            
Percent of net assets   3.10%         3.10%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Pressurized Holdings, LLC Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:PressurizedHoldingsLlcMember whfcl:PressurizedHoldingsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Chemicals Diversified Chemicals Diversified Chemicals Diversified Chemicals Diversified Chemicals   Diversified Chemicals  
Acquisition Date Mar. 16, 2023 Mar. 16, 2023            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Pressurized Holdings, LLC Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:PressurizedHoldingsLlcMember whfcl:PressurizedHoldingsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Chemicals Diversified Chemicals Diversified Chemicals Diversified Chemicals Diversified Chemicals   Diversified Chemicals  
Spread Above Index 14.00% 14.00% 14.00% 14.00% 14.00%   14.00%  
PIK interest rate 14.00% 14.00% 14.00% 14.00% 14.00%   14.00%  
Acquisition Date Mar. 16, 2023 Mar. 16, 2023            
Investments, amortized cost $ 4,537,000 $ 4,537,000            
Investments, fair value $ 4,784,000 $ 1,657,000           251,000
Percent of net assets 1.80% 0.60% 1.80% 1.80% 1.80%   0.60%  
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Principal Lighting Group, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:PrincipalLightingGroupLlcMember whfcl:PrincipalLightingGroupLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] whfcl:ElectronicEquipmentAndInstrumentsMember Electrical Components And Equipment [Member] whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember   Electrical Components And Equipment [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.25% 5.25% 5.25% 5.25% 5.25%   5.25%  
Interest Rate 8.96% 9.81% 8.96% 8.96% 8.96%   9.81%  
Acquisition Date Dec. 03, 2024 Dec. 03, 2024            
Maturity Date Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030   Nov. 04, 2030  
Investments, fair value $ 4,000              
Investment, Identifier [Axis]: Principal Lighting Group, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:PrincipalLightingGroupLlcMember whfcl:PrincipalLightingGroupLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] whfcl:ElectronicEquipmentAndInstrumentsMember Electrical Components And Equipment [Member] whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember   Electrical Components And Equipment [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.25% 5.25% 5.25% 5.25% 5.25%   5.25%  
Interest Rate 8.96% 9.81% 8.96% 8.96% 8.96%   9.81%  
Acquisition Date Dec. 03, 2024 Dec. 03, 2024            
Maturity Date Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030   Nov. 04, 2030  
Principal/Share Amount $ 3,353,000 $ 3,531,000            
Investments, amortized cost 3,312,000 3,479,000            
Investments, fair value $ 3,343,000 $ 3,479,000            
Investment, Identifier [Axis]: Quest Events, LLC Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Quest Events, LLC [Member] Quest Events, LLC [Member]            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services   Diversified Support Services  
Acquisition Date Dec. 28, 2018 Dec. 28, 2018            
Investment owned shares | shares 385   385 385 385      
Principal/Share Amount   $ 333,000            
Investments, amortized cost $ 385,000 376,000            
Investments, fair value   $ 149,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] Quest Events, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services   Diversified Support Services Diversified Support Services Diversified Support Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 7.50%   7.50% 7.50% 7.50%      
Interest Rate 11.48%   11.48% 11.48% 11.48%      
Acquisition Date Mar. 21, 2025              
Maturity Date Sep. 30, 2027   Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027      
Principal/Share Amount $ 124,000              
Investments, amortized cost 122,000              
Investments, fair value $ 113,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   Quest Events, LLC [Member]            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Diversified Support Services         Diversified Support Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   2.00%         2.00%  
Spread Above Index   7.00%         7.00%  
Interest Rate   11.59%         11.59%  
Acquisition Date   Jul. 19, 2019            
Maturity Date   Sep. 30, 2026         Sep. 30, 2026  
Principal/Share Amount   $ 247,000            
Investments, amortized cost   246,000            
Investments, fair value   $ 248,000            
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Quest Events, LLC [Member] Quest Events, LLC [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services Diversified Support Services   Diversified Support Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 6.50% 6.75% 6.75% 6.75%   6.50%  
Interest Rate 10.48% 10.90% 10.48% 10.48% 10.48%   10.90%  
Acquisition Date Sep. 13, 2024 Sep. 13, 2024            
Maturity Date Sep. 30, 2027 Sep. 30, 2026 Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027   Sep. 30, 2026  
Principal/Share Amount $ 1,270,000 $ 480,000            
Investments, amortized cost 1,258,000 472,000            
Investments, fair value $ 1,187,000 $ 473,000            
Percent of net assets 0.50% 0.20% 0.50% 0.50% 0.50%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   Quest Events, LLC [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Diversified Support Services         Diversified Support Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   2.00%         2.00%  
Spread Above Index   7.00%         7.00%  
Interest Rate   11.59%         11.59%  
Acquisition Date   Jul. 19, 2019            
Maturity Date   Sep. 30, 2026         Sep. 30, 2026  
Principal/Share Amount   $ 11,592,000            
Investments, amortized cost   11,563,000            
Investments, fair value   $ 11,592,000            
Investment, Identifier [Axis]: Quest Events, LLC, First Lien Secured Revolving Loan, One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] Quest Events, LLC [Member]              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services   Diversified Support Services Diversified Support Services Diversified Support Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 7.50%   7.50% 7.50% 7.50%      
Interest Rate 11.48%   11.48% 11.48% 11.48%      
Acquisition Date Jul. 19, 2019              
Maturity Date Sep. 30, 2027   Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027      
Principal/Share Amount $ 288,000              
Investments, amortized cost 288,000              
Investments, fair value $ 262,000              
Investment, Identifier [Axis]: Quest Events, LLC, First Lien Secured Term Loan, One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] Quest Events, LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Diversified Support Services   Diversified Support Services Diversified Support Services Diversified Support Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 2.00%   2.00% 2.00% 2.00%      
Spread Above Index 7.50%   7.50% 7.50% 7.50%      
Interest Rate 11.48%   11.48% 11.48% 11.48%      
Acquisition Date Jul. 19, 2019              
Maturity Date Sep. 30, 2027   Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027      
Principal/Share Amount $ 11,668,000              
Investments, amortized cost 11,655,000              
Investments, fair value $ 11,041,000              
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 5.25% 5.50% 5.50% 5.50%   5.25%  
Interest Rate 9.49% 9.99% 9.49% 9.49% 9.49%   9.99%  
Acquisition Date Jan. 27, 2021 Jan. 27, 2021            
Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029   Jan. 02, 2029  
Principal/Share Amount $ 2,916,000 $ 2,946,000            
Investments, amortized cost 2,898,000 2,922,000            
Investments, fair value $ 2,827,000 $ 2,946,000            
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:RCKCAcquisitionsLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   IT Consulting And Other Services         IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.25%         5.25%  
Interest Rate   9.99%         9.99%  
Acquisition Date   Jan. 27, 2021            
Maturity Date   Jan. 02, 2029         Jan. 02, 2029  
Investments, fair value   $ 11,000            
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 5.25% 5.50% 5.50% 5.50%   5.25%  
Interest Rate 9.32% 9.73% 9.32% 9.32% 9.32%   9.73%  
Acquisition Date Jan. 27, 2021 Jan. 27, 2021            
Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029   Jan. 02, 2029  
Principal/Share Amount $ 10,809,000 $ 10,923,000            
Investments, amortized cost 10,747,000 10,839,000            
Investments, fair value $ 10,481,000 $ 10,923,000            
Investment, Identifier [Axis]: RCKC Acquisitions LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:RCKCAcquisitionsLLCMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.50%   5.50% 5.50% 5.50%      
Interest Rate 9.49%   9.49% 9.49% 9.49%      
Acquisition Date Jan. 27, 2021              
Maturity Date Jan. 02, 2029   Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029      
Investments, fair value $ (35,000)              
Investment, Identifier [Axis]: RLJ Pro-Vac, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:RLJPro-VacInc.Member whfcl:RLJPro-VacInc.Member            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services Environmental & Facilities Services   Environmental & Facilities Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.75% 6.25% 6.75% 6.75% 6.75%   6.25%  
Interest Rate 10.72% 10.71% 10.72% 10.72% 10.72%   10.71%  
Acquisition Date Jan. 23, 2024 Jan. 23, 2024            
Maturity Date Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026   Dec. 31, 2026  
Principal/Share Amount $ 6,592,000 $ 6,659,000            
Investments, amortized cost 6,546,000 6,566,000            
Investments, fair value $ 6,396,000 $ 6,637,000            
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:RewardsNetworkInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Finance   Specialized Finance Specialized Finance Specialized Finance      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.76%   9.76% 9.76% 9.76%      
Acquisition Date Dec. 05, 2025              
Maturity Date Dec. 05, 2031   Dec. 05, 2031 Dec. 05, 2031 Dec. 05, 2031      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:RewardsNetworkInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Finance   Specialized Finance Specialized Finance Specialized Finance      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.82%   9.82% 9.82% 9.82%      
Acquisition Date Dec. 05, 2025              
Maturity Date Dec. 05, 2031   Dec. 05, 2031 Dec. 05, 2031 Dec. 05, 2031      
Principal/Share Amount $ 638,000              
Investments, amortized cost 627,000              
Investments, fair value $ 627,000              
Percent of net assets 0.20%   0.20% 0.20% 0.20%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:RewardsNetworkInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Finance   Specialized Finance Specialized Finance Specialized Finance      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.75%   0.75% 0.75% 0.75%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 9.76%   9.76% 9.76% 9.76%      
Acquisition Date Dec. 05, 2025              
Maturity Date Dec. 05, 2031   Dec. 05, 2031 Dec. 05, 2031 Dec. 05, 2031      
Principal/Share Amount $ 10,213,000              
Investments, amortized cost 10,036,000              
Investments, fair value $ 10,034,000              
Percent of net assets 3.90%   3.90% 3.90% 3.90%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Ribbon Communications Operating Company, Inc. [Member] Ribbon Communications Operating Company, Inc. [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 9.97% 10.59% 9.97% 9.97% 9.97%   10.59%  
Acquisition Date Jun. 21, 2024 Jun. 21, 2024            
Maturity Date Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029   Jun. 21, 2029  
Investments, fair value $ 12,000 $ 9,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Ribbon Communications Operating Company, Inc. [Member] Ribbon Communications Operating Company, Inc. [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Systems Software Systems Software Systems Software Systems Software Systems Software   Systems Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 9.97% 10.59% 9.97% 9.97% 9.97%   10.59%  
Acquisition Date Jun. 21, 2024 Jun. 21, 2024            
Maturity Date Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029   Jun. 21, 2029  
Principal/Share Amount $ 8,602,000 $ 8,756,000            
Investments, amortized cost 8,483,000 8,600,000            
Investments, fair value $ 8,631,000 $ 8,692,000            
Percent of net assets 3.30% 3.00% 3.30% 3.30% 3.30%   3.00%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Ross-Simons Topco, LP Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:Ross-SimonsTopcoLPMember whfcl:Ross-SimonsTopcoLPMember            
Investment, Type [Extensible Enumeration] whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Broadline Retail Broadline Retail Broadline Retail Broadline Retail Broadline Retail   Broadline Retail  
Spread Above Index 8.00% 8.00% 8.00% 8.00% 8.00%   8.00%  
PIK interest rate 8.00% 8.00% 8.00% 8.00% 8.00%   8.00%  
Acquisition Date Dec. 04, 2020 Dec. 04, 2020            
Investment owned shares | shares 600 600 600 600 600   600  
Investments, amortized cost $ 514,000 $ 514,000            
Investments, fair value $ 735,000 $ 756,000            
Percent of net assets 0.30% 0.30% 0.30% 0.30% 0.30%   0.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ScicBuyerInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Building Products   Building Products Building Products Building Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Jun. 04, 2025              
Maturity Date Mar. 28, 2031   Mar. 28, 2031 Mar. 28, 2031 Mar. 28, 2031      
Principal/Share Amount $ 295,000              
Investments, amortized cost 293,000              
Investments, fair value $ 319,000              
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ScicBuyerInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Building Products   Building Products Building Products Building Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Jun. 04, 2025              
Maturity Date Mar. 28, 2031   Mar. 28, 2031 Mar. 28, 2031 Mar. 28, 2031      
Investments, fair value $ 25,000              
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ScicBuyerInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Building Products   Building Products Building Products Building Products      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Jun. 04, 2025              
Maturity Date Mar. 28, 2031   Mar. 28, 2031 Mar. 28, 2031 Mar. 28, 2031      
Principal/Share Amount $ 9,090,000              
Investments, amortized cost 8,970,000              
Investments, fair value $ 9,142,000              
Investment, Identifier [Axis]: Salon Republic Holdings, LLC (d/b/a Salon Republic, LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:SalonRepublicHoldingsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 8.00%   8.00% 8.00% 8.00%      
Interest Rate 11.82%   11.82% 11.82% 11.82%      
Acquisition Date Dec. 02, 2022              
Maturity Date Dec. 02, 2027   Dec. 02, 2027 Dec. 02, 2027 Dec. 02, 2027      
Principal/Share Amount $ 1,652,000              
Investments, amortized cost 1,637,000              
Investments, fair value $ 1,653,000              
Percent of net assets 0.60%   0.60% 0.60% 0.60%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Salon Republic Holdings, LLC (d/b/a Salon Republic, LLC) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:SalonRepublicHoldingsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 8.00%   8.00% 8.00% 8.00%      
Interest Rate 11.82%   11.82% 11.82% 11.82%      
Acquisition Date Dec. 02, 2022              
Maturity Date Dec. 02, 2027   Dec. 02, 2027 Dec. 02, 2027 Dec. 02, 2027      
Investments, fair value $ 8,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Salon Republic Holdings, LLC (d/b/a Salon Republic, LLC) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:SalonRepublicHoldingsLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 8.00%   8.00% 8.00% 8.00%      
Interest Rate 11.82%   11.82% 11.82% 11.82%      
Acquisition Date Dec. 02, 2022              
Maturity Date Dec. 02, 2027   Dec. 02, 2027 Dec. 02, 2027 Dec. 02, 2027      
Principal/Share Amount $ 5,032,000              
Investments, amortized cost 4,974,000              
Investments, fair value $ 5,021,000              
Percent of net assets 1.90%   1.90% 1.90% 1.90%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:SalonRepublicHoldingsLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Specialized Consumer Services         Specialized Consumer Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.46%         12.46%  
Acquisition Date   Dec. 02, 2022            
Maturity Date   Dec. 02, 2027         Dec. 02, 2027  
Principal/Share Amount   $ 1,669,000            
Investments, amortized cost   1,641,000            
Investments, fair value   $ 1,672,000            
Percent of net assets   0.60%         0.60%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:SalonRepublicHoldingsLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Specialized Consumer Services         Specialized Consumer Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.46%         12.46%  
Acquisition Date   Dec. 02, 2022            
Maturity Date   Dec. 02, 2027         Dec. 02, 2027  
Investments, fair value   $ 13,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   whfcl:SalonRepublicHoldingsLlcMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Specialized Consumer Services         Specialized Consumer Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   8.00%         8.00%  
Interest Rate   12.46%         12.46%  
Acquisition Date   Dec. 02, 2022            
Maturity Date   Dec. 02, 2027         Dec. 02, 2027  
Principal/Share Amount   $ 5,076,000            
Investments, amortized cost   4,988,000            
Investments, fair value   $ 5,063,000            
Percent of net assets   1.80%         1.80%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Salon Republic Investments LLC, Common Stock                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember            
Investment, Type [Extensible Enumeration] Common Stock [Member] Common Stock [Member] Common Stock [Member] Common Stock [Member] Common Stock [Member]   Common Stock [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services   Specialized Consumer Services  
Acquisition Date Dec. 02, 2022 Dec. 02, 2022            
Investment owned shares | shares 400   400 400 400      
Principal/Share Amount   $ 400,000            
Investments, amortized cost $ 400,000 400,000            
Investments, fair value $ 6,000 $ 132,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Salon Republic Investments LLC, Preferred Stock                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember            
Investment, Type [Extensible Enumeration] us-gaap:PreferredStockMember us-gaap:PreferredStockMember us-gaap:PreferredStockMember us-gaap:PreferredStockMember us-gaap:PreferredStockMember   us-gaap:PreferredStockMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services   Specialized Consumer Services  
Spread Above Index 8.00% 8.00% 8.00% 8.00% 8.00%   8.00%  
PIK interest rate 8.00% 8.00% 8.00% 8.00% 8.00%   8.00%  
Acquisition Date Dec. 02, 2022 Dec. 02, 2022            
Investment owned shares | shares 200   200 200 200      
Principal/Share Amount   $ 200,000            
Investments, amortized cost $ 200,000 200,000            
Investments, fair value $ 265,000 $ 242,000            
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10%   0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] true false true true true   false  
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Home Furnishings Home Furnishings Home Furnishings Home Furnishings Home Furnishings   Home Furnishings  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 6.50% 5.50% 5.50% 5.50%   6.50%  
Interest Rate 9.37% 11.28% 9.37% 9.37% 9.37%   11.28%  
Acquisition Date Nov. 07, 2025 Oct. 12, 2021            
Maturity Date Nov. 07, 2030 Oct. 12, 2026 Nov. 07, 2030 Nov. 07, 2030 Nov. 07, 2030   Oct. 12, 2026  
Investments, fair value   $ 5,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Home Furnishings Home Furnishings Home Furnishings Home Furnishings Home Furnishings   Home Furnishings  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 6.50% 5.50% 5.50% 5.50%   6.50%  
Interest Rate 9.37% 11.28% 9.37% 9.37% 9.37%   11.28%  
Acquisition Date Nov. 07, 2025 Oct. 12, 2021            
Maturity Date Nov. 07, 2030 Oct. 12, 2026 Nov. 07, 2030 Nov. 07, 2030 Nov. 07, 2030   Oct. 12, 2026  
Principal/Share Amount $ 13,455,000 $ 22,590,000            
Investments, amortized cost 13,259,000 22,401,000            
Investments, fair value $ 13,255,000 $ 22,441,000            
Percent of net assets 5.10% 7.80% 5.10% 5.10% 5.10%   7.80%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:SmaltoInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Household Appliances   Household Appliances Household Appliances Household Appliances      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Euro Interbank Offered Rate One Month Term [Member]   Euro Interbank Offered Rate One Month Term [Member] Euro Interbank Offered Rate One Month Term [Member] Euro Interbank Offered Rate One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.00%   6.00% 6.00% 6.00%      
Interest Rate 7.90%   7.90% 7.90% 7.90%      
Acquisition Date May 04, 2022              
Maturity Date Apr. 28, 2028   Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028      
Principal/Share Amount | €       € 6,198        
Investments, amortized cost $ 6,480,000              
Investments, fair value $ 7,281,000              
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan One                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:SmaltoInc.Member whfcl:SmaltoInc.Member            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Household Appliances   Household Appliances Household Appliances Household Appliances      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.57% 10.21% 9.57% 9.57% 9.57%   10.21%  
Acquisition Date May 04, 2022 May 04, 2022            
Maturity Date Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028   Apr. 28, 2028  
Principal/Share Amount $ 944,000 $ 978,000            
Investments, amortized cost 936,000 967,000            
Investments, fair value $ 944,000 $ 978,000            
Investment, Identifier [Axis]: Smalto Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:SmaltoInc.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Household Appliances         Household Appliances  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:EuroInterbankOfferedRateMember         whfcl:EuroInterbankOfferedRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.00%         6.00%  
Interest Rate   8.86%         8.86%  
Acquisition Date   May 04, 2022            
Maturity Date   Apr. 28, 2028         Apr. 28, 2028  
Principal/Share Amount   $ 6,423,000            
Investments, amortized cost   6,682,000            
Investments, fair value   $ 6,654,000            
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Class A Common Stock                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Controlled affiliate company investments, Non-controlled affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Controlled affiliate company investments, Non-controlled affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember            
Investment, Type [Extensible Enumeration] us-gaap:CommonClassAMember whfcl:ClassCommonStockMember us-gaap:CommonClassAMember us-gaap:CommonClassAMember us-gaap:CommonClassAMember   whfcl:ClassCommonStockMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Acquisition Date Jun. 29, 2020 Jun. 29, 2020            
Investment owned shares | shares 2   2 2 2      
Principal/Share Amount   $ 2,000            
Investments, amortized cost $ 1,941,000 1,941,000            
Investments, fair value $ 507,000 $ 173,000            
Percent of net assets 0.20% 0.10% 0.20% 0.20% 0.20%   0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc First Lien Secured Term Loan C                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredTermLoanCMember whfcl:FirstLienSecuredTermLoanCMember whfcl:FirstLienSecuredTermLoanCMember whfcl:FirstLienSecuredTermLoanCMember whfcl:FirstLienSecuredTermLoanCMember   whfcl:FirstLienSecuredTermLoanCMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Spread Above Index 9.50% 9.50% 9.50% 9.50% 9.50%   9.50%  
PIK interest rate 9.50%   9.50% 9.50% 9.50%      
PIK interest rate   9.50%         9.50%  
Acquisition Date Jun. 29, 2020 Jun. 29, 2020            
Maturity Date Sep. 30, 2026   Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026      
Principal/Share Amount $ 2,098,000 $ 1,822,000            
Investments, amortized cost 2,095,000 1,819,000            
Investments, fair value $ 2,098,000 $ 1,790,000            
Percent of net assets 0.80% 0.60% 0.80% 0.80% 0.80%   0.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Warrants                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember            
Investment, Type [Extensible Enumeration] Warrant [Member] Warrant [Member] Warrant [Member] Warrant [Member] Warrant [Member]   Warrant [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities Leisure Facilities   Leisure Facilities  
Acquisition Date Jun. 29, 2020 Jun. 29, 2020            
Investment owned shares | shares 1   1 1 1      
Principal/Share Amount   $ 1,000            
Investments, amortized cost $ 793,000 793,000            
Investments, fair value $ 205,000 $ 70,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:SourceCodeHoldingsLLCMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Technology Hardware, Storage & Peripherals         Technology Hardware, Storage & Peripherals  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Aug. 10, 2021            
Maturity Date   Jul. 30, 2027         Jul. 30, 2027  
Principal/Share Amount   $ 3,872,000            
Investments, amortized cost   3,839,000            
Investments, fair value   $ 3,854,000            
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:SourceCodeHoldingsLLCMember            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Technology Hardware, Storage & Peripherals         Technology Hardware, Storage & Peripherals  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.96%         10.96%  
Acquisition Date   Aug. 10, 2021            
Maturity Date   Jul. 30, 2027         Jul. 30, 2027  
Principal/Share Amount   $ 14,162,000            
Investments, amortized cost   14,041,000            
Investments, fair value   $ 14,095,000            
Investment, Identifier [Axis]: Source Code Holdings, LLC., First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:SourceCodeHoldingsLLCMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Technology Hardware, Storage & Peripherals   Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Aug. 10, 2021              
Maturity Date Jul. 30, 2027   Jul. 30, 2027 Jul. 30, 2027 Jul. 30, 2027      
Principal/Share Amount $ 3,831,000              
Investments, amortized cost 3,811,000              
Investments, fair value $ 3,831,000              
Investment, Identifier [Axis]: Source Code Holdings, LLC., First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:SourceCodeHoldingsLLCMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Technology Hardware, Storage & Peripherals   Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.32%   10.32% 10.32% 10.32%      
Acquisition Date Aug. 10, 2021              
Maturity Date Jul. 30, 2027   Jul. 30, 2027 Jul. 30, 2027 Jul. 30, 2027      
Principal/Share Amount $ 14,009,000              
Investments, amortized cost 13,935,000              
Investments, fair value $ 14,009,000              
Investment, Identifier [Axis]: Sterling Pure Blocker, LLC (d/b/a Banner Industries, Inc.) Class B Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:SterlingPureBlockerLlcMember whfcl:SterlingPureBlockerLlcMember            
Investment, Type [Extensible Enumeration] whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Acquisition Date Dec. 01, 2023 Dec. 01, 2023            
Investment owned shares | shares 404   404 404 404      
Principal/Share Amount   $ 404,000            
Investments, amortized cost $ 404,000 404,000            
Investments, fair value $ 57,000 $ 388,000            
Percent of net assets   0.10%         0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Surge Amuze Holdings Inc [Member] Surge Amuze Holdings Inc [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.00% 6.25% 6.25% 6.25%   6.00%  
Interest Rate 9.99% 10.46% 9.99% 9.99% 9.99%   10.46%  
Acquisition Date Sep. 06, 2024 Sep. 06, 2024            
Maturity Date Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029   Sep. 06, 2029  
Principal/Share Amount $ 1,002,000 $ 584,000            
Investments, amortized cost 987,000 573,000            
Investments, fair value $ 1,000,000 $ 577,000            
Percent of net assets 0.40% 0.20% 0.40% 0.40% 0.40%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Surge Amuze Holdings Inc [Member] Surge Amuze Holdings Inc [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member] Prime Rate [Member] Base Rate [Member] Base Rate [Member] Base Rate [Member]   Prime Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.90% 5.00% 5.90% 5.90% 5.90%   5.00%  
Interest Rate 10.82% 12.50% 10.82% 10.82% 10.82%   12.50%  
Acquisition Date Sep. 06, 2024 Sep. 06, 2024            
Maturity Date Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029   Sep. 06, 2029  
Principal/Share Amount $ 451,000 $ 585,000            
Investments, amortized cost 444,000 574,000            
Investments, fair value $ 450,000 $ 576,000            
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Surge Amuze Holdings Inc [Member] Surge Amuze Holdings Inc [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Leisure Products Leisure Products Leisure Products Leisure Products Leisure Products   Leisure Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.00% 6.25% 6.25% 6.25%   6.00%  
Interest Rate 9.99% 10.44% 9.99% 9.99% 9.99%   10.44%  
Acquisition Date Sep. 06, 2024 Sep. 06, 2024            
Maturity Date Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029   Sep. 06, 2029  
Principal/Share Amount $ 5,679,000 $ 5,737,000            
Investments, amortized cost 5,596,000 5,629,000            
Investments, fair value $ 5,645,000 $ 5,643,000            
Percent of net assets 2.20% 2.00% 2.20% 2.20% 2.20%   2.00%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Tot Group, Inc. [Member] Tot Group, Inc. [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services   Transaction & Payment Processing Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.25% 7.50% 7.25% 7.25% 7.25%   7.50%  
Interest Rate 10.92% 11.83% 10.92% 10.92% 10.92%   11.83%  
Acquisition Date Jun. 28, 2024 Jun. 28, 2024            
Maturity Date Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029   Jun. 28, 2029  
Principal/Share Amount $ 1,103,000              
Investments, amortized cost 1,084,000              
Investments, fair value $ 1,091,000 $ (1,000)            
Percent of net assets 0.40%   0.40% 0.40% 0.40%      
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Tot Group, Inc. [Member] Tot Group, Inc. [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services   Transaction & Payment Processing Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.25% 7.50% 7.25% 7.25% 7.25%   7.50%  
Interest Rate 10.92% 11.83% 10.92% 10.92% 10.92%   11.83%  
Acquisition Date Jun. 28, 2024 Jun. 28, 2024            
Maturity Date Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029   Jun. 28, 2029  
Investments, fair value $ 1,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Tot Group, Inc. [Member] Tot Group, Inc. [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services Transaction & Payment Processing Services   Transaction & Payment Processing Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.25% 7.50% 7.25% 7.25% 7.25%   7.50%  
Interest Rate 10.92% 11.83% 10.92% 10.92% 10.92%   11.83%  
Acquisition Date Jun. 28, 2024 Jun. 28, 2024            
Maturity Date Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029   Jun. 28, 2029  
Principal/Share Amount $ 9,146,000 $ 8,239,000            
Investments, amortized cost 9,000,000 8,074,000            
Investments, fair value $ 9,023,000 $ 8,067,000            
Percent of net assets 3.40% 2.80% 3.40% 3.40% 3.40%   2.80%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: TVG I-EMSI Parent, LLC Class A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TvgIEmsiParentLlcMember              
Investment, Type [Extensible Enumeration] whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Education Services   Education Services Education Services Education Services      
Acquisition Date Sep. 01, 2025              
Principal/Share Amount $ 20,765,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: TVG I-EMSI Parent, LLC Class B Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TvgIEmsiParentLlcMember              
Investment, Type [Extensible Enumeration] whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Education Services   Education Services Education Services Education Services      
Acquisition Date Sep. 01, 2025              
Principal/Share Amount $ 2,000              
Investments, amortized cost 3,291,000              
Investments, fair value $ 3,291,000              
Percent of net assets 1.30%   1.30% 1.30% 1.30%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: TableTrust Brands LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:TabletrustBrandsLlcMember whfcl:TabletrustBrandsLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats Packaged Foods & Meats   Packaged Foods & Meats  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.75% 5.75% 5.75% 5.75% 5.75%   5.75%  
Interest Rate 9.57% 10.22% 9.57% 9.57% 9.57%   10.22%  
Acquisition Date Dec. 24, 2024 Dec. 24, 2024            
Maturity Date Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028   Jun. 28, 2028  
Principal/Share Amount $ 2,480,000 $ 2,505,000            
Investments, amortized cost 2,453,000 2,468,000            
Investments, fair value $ 2,480,000 $ 2,468,000            
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Telestream Holdings Corporation [Member] Telestream Holdings Corporation [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals   Technology Hardware, Storage & Peripherals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 9.75% 6.25% 6.25% 6.25%   9.75%  
PIK interest rate 10.19% 14.21% 10.19% 10.19% 10.19%   14.21%  
Acquisition Date Jun. 07, 2025 Oct. 15, 2020            
Maturity Date Jun. 07, 2028 Oct. 15, 2025 Jun. 07, 2028 Jun. 07, 2028 Jun. 07, 2028   Oct. 15, 2025  
Principal/Share Amount   $ 1,116,000            
Investments, amortized cost   1,051,000            
Investments, fair value $ 20,000 $ 1,009,000            
Percent of net assets   0.40%         0.40%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Telestream Holdings Corporation [Member] Telestream Holdings Corporation [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals   Technology Hardware, Storage & Peripherals  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 9.75% 6.25% 6.25% 6.25%   9.75%  
PIK interest rate 10.19% 14.21% 10.19% 10.19% 10.19%   14.21%  
Acquisition Date Jun. 07, 2025 Oct. 15, 2020            
Maturity Date Jun. 07, 2028 Oct. 15, 2025 Jun. 07, 2028 Jun. 07, 2028 Jun. 07, 2028   Oct. 15, 2025  
Principal/Share Amount $ 11,437,000 $ 18,547,000            
Investments, amortized cost 11,437,000 17,496,000            
Investments, fair value $ 11,437,000 $ 17,063,000            
Percent of net assets 4.40% 5.90% 4.40% 4.40% 4.40%   5.90%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Telestream Topco 2 LLC (d/b/a Telestream Holdings Corporation) Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TelestreamTopco2LlcMember              
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember   whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Technology Hardware, Storage & Peripherals   Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals      
Acquisition Date Jun. 07, 2025              
Principal/Share Amount $ 497,000              
Investments, amortized cost 7,109,000              
Investments, fair value $ 8,027,000              
Percent of net assets 3.10%   3.10% 3.10% 3.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TexasExpressWashLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.23%   10.23% 10.23% 10.23%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 26, 2030   Nov. 26, 2030 Nov. 26, 2030 Nov. 26, 2030      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TexasExpressWashLlcMember              
Investment, Type [Extensible Enumeration] whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.23%   10.23% 10.23% 10.23%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 26, 2030   Nov. 26, 2030 Nov. 26, 2030 Nov. 26, 2030      
Principal/Share Amount $ 104,000              
Investments, amortized cost 100,000              
Investments, fair value $ 100,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TexasExpressWashLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.23%   10.23% 10.23% 10.23%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 26, 2030   Nov. 26, 2030 Nov. 26, 2030 Nov. 26, 2030      
Principal/Share Amount $ 11,128,000              
Investments, amortized cost 10,778,000              
Investments, fair value $ 10,776,000              
Percent of net assets 4.10%   4.10% 4.10% 4.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Texas Express Wash, LLC Second Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TexasExpressWashLlcMember              
Investment, Type [Extensible Enumeration] whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Spread Above Index 14.00%   14.00% 14.00% 14.00%      
Interest Rate 14.00%   14.00% 14.00% 14.00%      
Cash interest rate 7.00%   7.00% 7.00% 7.00%      
PIK interest rate 7.00%   7.00% 7.00% 7.00%      
Acquisition Date Nov. 26, 2025              
Maturity Date Nov. 26, 2031   Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031      
Principal/Share Amount $ 1,569,000              
Investments, amortized cost 1,436,000              
Investments, fair value $ 1,435,000              
Percent of net assets 0.60%   0.60% 0.60% 0.60%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Texas Wash Holdings, LLC (d/b/a ClearWater Express Wash) Warrants                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:TexasWashHoldingsLlcMember              
Investment, Type [Extensible Enumeration] Warrant [Member]   Warrant [Member] Warrant [Member] Warrant [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Specialized Consumer Services   Specialized Consumer Services Specialized Consumer Services Specialized Consumer Services      
Acquisition Date Nov. 26, 2025              
Investments, amortized cost $ 197,000              
Investments, fair value $ 197,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ImpactAdvisorsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Water Utilities [Member]   Water Utilities [Member] Water Utilities [Member] Water Utilities [Member]      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.90%   8.90% 8.90% 8.90%      
Acquisition Date Mar. 05, 2025              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Principal/Share Amount $ 802,000              
Investments, amortized cost 793,000              
Investments, fair value $ 806,000              
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ImpactAdvisorsLlcMember              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Water Utilities [Member]   Water Utilities [Member] Water Utilities [Member] Water Utilities [Member]      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member]   Base Rate [Member] Base Rate [Member] Base Rate [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.84%   8.84% 8.84% 8.84%      
Acquisition Date Mar. 05, 2025              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Principal/Share Amount $ 312,000              
Investments, amortized cost 308,000              
Investments, fair value $ 317,000              
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:ImpactAdvisorsLlcMember              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Water Utilities [Member]   Water Utilities [Member] Water Utilities [Member] Water Utilities [Member]      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.00%   5.00% 5.00% 5.00%      
Interest Rate 8.84%   8.84% 8.84% 8.84%      
Acquisition Date Mar. 05, 2025              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Principal/Share Amount $ 4,049,000              
Investments, amortized cost 3,998,000              
Investments, fair value $ 4,049,000              
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Household Products Household Products Household Products Household Products Household Products   Household Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 6.50% 7.50% 7.50% 7.50%   6.50%  
Interest Rate 11.61% 10.97% 11.61% 11.61% 11.61%   10.97%  
Cash interest rate 10.61% 10.22% 10.61% 10.61% 10.61%   10.22%  
PIK interest rate 1.00% 0.75% 1.00% 1.00% 1.00%   0.75%  
Acquisition Date Apr. 05, 2021 Apr. 05, 2021            
Maturity Date Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026   Apr. 05, 2026  
Principal/Share Amount   $ 798,000            
Investments, amortized cost   795,000            
Investments, fair value $ (132,000) $ 761,000            
Percent of net assets (0.10%) 0.30% (0.10%) (0.10%) (0.10%)   0.30%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Household Products Household Products Household Products Household Products Household Products   Household Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 7.25% 7.50% 7.50% 7.50%   7.25%  
Interest Rate 11.61% 12.05% 11.61% 11.61% 11.61%   12.05%  
Cash interest rate 10.61% 11.30% 10.61% 10.61% 10.61%   11.30%  
PIK interest rate 1.00% 0.75% 1.00% 1.00% 1.00%   0.75%  
Acquisition Date Apr. 05, 2021 Apr. 05, 2021            
Maturity Date Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026   Apr. 05, 2026  
Principal/Share Amount $ 11,409,000 $ 11,350,000            
Investments, amortized cost 11,400,000 11,309,000            
Investments, fair value $ 9,790,000 $ 10,895,000            
Percent of net assets 3.80% 3.80% 3.80% 3.80% 3.80%   3.80%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Token Buyer, Inc First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:TokenBuyerIncMember whfcl:TokenBuyerIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Household Appliances Household Appliances Household Appliances Household Appliances Household Appliances   Household Appliances  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 0.50% 0.50% 0.50% 0.50% 0.50%   0.50%  
Spread Above Index 6.00% 6.00% 6.00% 6.00% 6.00%   6.00%  
Interest Rate 9.99% 10.74% 9.99% 9.99% 9.99%   10.74%  
Acquisition Date May 26, 2022 May 26, 2022            
Maturity Date May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029   May 31, 2029  
Principal/Share Amount $ 1,587,000 $ 7,070,000            
Investments, amortized cost 1,363,000 6,709,000            
Investments, fair value $ 1,199,000 $ 5,658,000            
Percent of net assets 0.50% 2.00% 0.50% 0.50% 0.50%   2.00%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Trailhead Media LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Trailhead Media L L C [Member] Trailhead Media L L C [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 5.50% 5.50% 5.50% 5.50%   5.50%  
Interest Rate 9.17% 9.82% 9.17% 9.17% 9.17%   9.82%  
Cash interest rate 8.42% 9.07% 8.42% 8.42% 8.42%   9.07%  
PIK interest rate 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Acquisition Date Jan. 22, 2025 Dec. 30, 2024            
Maturity Date Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029   Dec. 28, 2029  
Investments, fair value $ (3,000)              
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Trailhead Media L L C [Member] Trailhead Media L L C [Member]            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 5.50% 5.50% 5.50% 5.50%   5.50%  
Interest Rate 9.17% 9.82% 9.17% 9.17% 9.17%   9.82%  
Cash interest rate 8.42% 9.07% 8.42% 8.42% 8.42%   9.07%  
PIK interest rate 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Acquisition Date Jan. 22, 2025 Dec. 30, 2024            
Maturity Date Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029   Dec. 28, 2029  
Investments, fair value $ (3,000)              
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] Trailhead Media L L C [Member] Trailhead Media L L C [Member]            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Advertising Advertising Advertising Advertising Advertising   Advertising  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 5.50% 5.50% 5.50% 5.50%   5.50%  
Interest Rate 9.17% 9.82% 9.17% 9.17% 9.17%   9.82%  
Cash interest rate 8.42% 9.07% 8.42% 8.42% 8.42%   9.07%  
PIK interest rate 0.75% 0.75% 0.75% 0.75% 0.75%   0.75%  
Acquisition Date Jan. 22, 2025 Dec. 30, 2024            
Maturity Date Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029   Dec. 28, 2029  
Principal/Share Amount $ 6,632,000 $ 6,648,000            
Investments, amortized cost 6,553,000 6,548,000            
Investments, fair value $ 6,532,000 $ 6,548,000            
Percent of net assets   2.30%         2.30%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: Transervice Holdings, Inc. (d/b/a Transervice Logistics, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:TranserviceHoldingsIncMember whfcl:TranserviceHoldingsIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics Air Freight & Logistics   Air Freight & Logistics  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 2.00% 2.00% 2.00% 2.00% 2.00%   2.00%  
Spread Above Index 7.25% 7.25% 7.25% 7.25% 7.25%   7.25%  
Interest Rate 11.07% 11.71% 11.07% 11.07% 11.07%   11.71%  
Acquisition Date Jun. 29, 2023 Jun. 29, 2023            
Maturity Date Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028   Jun. 29, 2028  
Principal/Share Amount $ 7,701,000 $ 8,663,000            
Investments, amortized cost 7,586,000 8,481,000            
Investments, fair value $ 7,701,000 $ 8,715,000            
Percent of net assets 3.00% 3.00% 3.00% 3.00% 3.00%   3.00%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Trimlite Buyer LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:TrimliteBuyerLLCMember whfcl:TrimliteBuyerLLCMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember country:CA srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   country:CA  
Investment, Industry Sector [Extensible Enumeration] Building Products Building Products Building Products Building Products Building Products   Building Products  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Canadian Overnight Repo Rate Average Three Months Term [Member] whfcl:CanadianOvernightRepoRateAverageMember Canadian Overnight Repo Rate Average Three Months Term [Member] Canadian Overnight Repo Rate Average Three Months Term [Member] Canadian Overnight Repo Rate Average Three Months Term [Member]   whfcl:CanadianOvernightRepoRateAverageMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.50% 6.50% 5.50% 5.50% 5.50%   6.50%  
Interest Rate 8.08% 9.99% 8.08% 8.08% 8.08%   9.99%  
Acquisition Date Jul. 27, 2021 Jul. 27, 2021            
Maturity Date Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027   Jul. 27, 2027  
Principal/Share Amount     $ 18,868       $ 18,984  
Investments, amortized cost     $ 14,957       15,006  
Investments, fair value $ 13,748,000           $ 13,206  
Percent of net assets 5.30% 4.60% 5.30% 5.30% 5.30%   4.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:TriplepointAcquisitionHoldingsLlcMember            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Construction & Engineering         Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.50%         5.50%  
Interest Rate   9.83%         9.83%  
Acquisition Date   Jun. 14, 2024            
Maturity Date   May 31, 2029         May 31, 2029  
Investments, fair value   $ 9,000            
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.25% 5.50% 5.25% 5.25% 5.25%   5.50%  
Interest Rate 8.92% 9.83% 8.92% 8.92% 8.92%   9.83%  
Acquisition Date Jun. 14, 2024 Jun. 14, 2024            
Maturity Date May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029   May 31, 2029  
Investments, fair value $ 18,000 $ 12,000            
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering Construction & Engineering   Construction & Engineering  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.25% 5.50% 5.25% 5.25% 5.25%   5.50%  
Interest Rate 8.92% 9.83% 8.92% 8.92% 8.92%   9.83%  
Acquisition Date Jun. 14, 2024 Jun. 14, 2024            
Maturity Date May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029   May 31, 2029  
Principal/Share Amount $ 8,093,000 $ 5,349,000            
Investments, amortized cost 7,975,000 5,254,000            
Investments, fair value $ 8,107,000 $ 5,338,000            
Investment, Identifier [Axis]: Turnberry Solutions, Inc.First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:TurnberrySolutionsInc.Member            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   IT Consulting And Other Services         IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.21%         10.21%  
Acquisition Date   Aug. 10, 2021            
Maturity Date   Sep. 02, 2026         Sep. 02, 2026  
Investments, fair value   $ 4,000            
Investment, Identifier [Axis]: Turnberry Solutions, Inc.First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration]   whfcl:TurnberrySolutionsInc.Member            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   IT Consulting And Other Services         IT Consulting And Other Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]         Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]  
Floor   1.00%         1.00%  
Spread Above Index   5.75%         5.75%  
Interest Rate   10.21%         10.21%  
Acquisition Date   Aug. 10, 2021            
Maturity Date   Sep. 02, 2026         Sep. 02, 2026  
Principal/Share Amount   $ 5,964,000            
Investments, amortized cost   5,924,000            
Investments, fair value   $ 5,964,000            
Investment, Identifier [Axis]: Turnberry Solutions., First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:TurnberrySolutionsInc.Member              
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.57%   9.57% 9.57% 9.57%      
Acquisition Date Aug. 10, 2021              
Maturity Date Mar. 02, 2028   Mar. 02, 2028 Mar. 02, 2028 Mar. 02, 2028      
Investments, fair value $ 2,000              
Investment, Identifier [Axis]: Turnberry Solutions., First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:TurnberrySolutionsInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 5.75%   5.75% 5.75% 5.75%      
Interest Rate 9.57%   9.57% 9.57% 9.57%      
Acquisition Date Aug. 10, 2021              
Maturity Date Mar. 02, 2028   Mar. 02, 2028 Mar. 02, 2028 Mar. 02, 2028      
Principal/Share Amount $ 5,902,000              
Investments, amortized cost 5,885,000              
Investments, fair value $ 5,902,000              
Investment, Identifier [Axis]: Twin Ridge CRS, LP (d/b/a CRS OneSource) Class A Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:TwinRidgeCrsLpMember whfcl:TwinRidgeCrsLpMember            
Investment, Type [Extensible Enumeration] whfcl:ClassCommonUnitsMember whfcl:ClassCommonUnitsMember whfcl:ClassCommonUnitsMember whfcl:ClassCommonUnitsMember whfcl:ClassCommonUnitsMember   whfcl:ClassCommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Food Distributors Food Distributors Food Distributors Food Distributors Food Distributors   Food Distributors  
Acquisition Date May 10, 2024 May 10, 2024            
Investment owned shares | shares 63   63 63 63      
Principal/Share Amount   $ 63,000            
Investments, amortized cost $ 317,000 317,000            
Investments, fair value $ 264,000 $ 350,000            
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10%   0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: UserZoom Technologies, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:UserzoomTechnologiesIncMember whfcl:UserzoomTechnologiesIncMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Application Software Application Software Application Software Application Software Application Software   Application Software  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member] Secured Overnight Financing Rate (SOFR) Six Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 7.50% 7.50% 7.50% 7.50% 7.50%   7.50%  
Interest Rate 11.63% 12.75% 11.63% 11.63% 11.63%   12.75%  
Acquisition Date Jan. 12, 2023 Jan. 12, 2023            
Maturity Date Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029   Apr. 05, 2029  
Principal/Share Amount $ 9,819,000 $ 9,819,000            
Investments, amortized cost 9,665,000 9,618,000            
Investments, fair value $ 9,621,000 $ 9,809,000            
Percent of net assets 3.70% 3.40% 3.70% 3.70% 3.70%   3.40%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Preferred Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:VistriaBlockedMgtInvestorLpMember              
Investment, Type [Extensible Enumeration] whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember whfcl:PreferredUnitsMember      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services   IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services      
Acquisition Date Apr. 10, 2023              
Investments, fair value $ 15,000              
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Series A Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:VistriaBlockedMgtInvestorLpMember whfcl:VistriaBlockedMgtInvestorLpMember            
Investment, Type [Extensible Enumeration] whfcl:SeriesUnitsMember whfcl:SeriesUnitsMember whfcl:SeriesUnitsMember whfcl:SeriesUnitsMember whfcl:SeriesUnitsMember   whfcl:SeriesUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services IT Consulting And Other Services   IT Consulting And Other Services  
Acquisition Date Apr. 10, 2023 Apr. 10, 2023            
Investments, amortized cost   $ 314,000            
Investments, fair value $ 308,000 $ 493,000            
Percent of net assets 0.10% 0.20% 0.10% 0.10% 0.10%   0.20%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) - First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   W Electric Intermediate Holdings, LLC [Member]            
Investment, Type [Extensible Enumeration]   whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Industrial Machinery & Supplies & Components         Industrial Machinery & Supplies & Components  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.86%         10.86%  
Cash interest rate   9.86%         9.86%  
PIK interest rate   1.00%         1.00%  
Acquisition Date   Aug. 15, 2024            
Maturity Date   Aug. 15, 2029         Aug. 15, 2029  
Investments, fair value   $ 9,000            
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) - First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration]   W Electric Intermediate Holdings, LLC [Member]            
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration]   Industrial Machinery & Supplies & Components         Industrial Machinery & Supplies & Components  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember         whfcl:SecuredOvernightFinancingRateMember  
Floor   1.00%         1.00%  
Spread Above Index   6.50%         6.50%  
Interest Rate   10.86%         10.86%  
Cash interest rate   9.86%         9.86%  
PIK interest rate   1.00%         1.00%  
Acquisition Date   Aug. 15, 2024            
Maturity Date   Aug. 15, 2029         Aug. 15, 2029  
Principal/Share Amount   $ 12,322,000            
Investments, amortized cost   12,124,000            
Investments, fair value   $ 12,216,000            
Percent of net assets   4.30%         4.30%  
Investment, Restriction Status [true false]   true         true  
Investment, Significant Unobservable Input [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] W Electric Intermediate Holdings, LLC [Member]              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Industrial Machinery & Supplies & Components   Industrial Machinery & Supplies & Components Industrial Machinery & Supplies & Components Industrial Machinery & Supplies & Components      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 6.50%   6.50% 6.50% 6.50%      
Interest Rate 10.22%   10.22% 10.22% 10.22%      
Cash interest rate 9.22%   9.22% 9.22% 9.22%      
PIK interest rate 1.00%   1.00% 1.00% 1.00%      
Acquisition Date Aug. 15, 2024              
Maturity Date Aug. 15, 2029   Aug. 15, 2029 Aug. 15, 2029 Aug. 15, 2029      
Principal/Share Amount $ 12,308,000              
Investments, amortized cost 12,154,000              
Investments, fair value $ 12,334,000              
Percent of net assets 4.70%   4.70% 4.70% 4.70%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Investment, Identifier [Axis]: WCHG Buyer, Inc. First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:WchgBuyerInc.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Commodity Chemicals   Commodity Chemicals Commodity Chemicals Commodity Chemicals      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]      
Floor 1.00%   1.00% 1.00% 1.00%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.47%   8.47% 8.47% 8.47%      
Acquisition Date Apr. 01, 2025              
Maturity Date Apr. 10, 2031   Apr. 10, 2031 Apr. 10, 2031 Apr. 10, 2031      
Principal/Share Amount $ 6,948,000              
Investments, amortized cost 6,918,000              
Investments, fair value $ 6,948,000              
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Equity                
Schedule of Investments [Line Items]                
Investment, Issuer Name [Extensible Enumeration] whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember            
Investment, Type [Extensible Enumeration] Equity Investments Equity Investments Equity Investments Equity Investments Equity Investments   Equity Investments  
Investments, fair value $ 21,602,000 $ 22,741,000           22,782,000
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Interests                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:WHFSTRSOhioSeniorLoanFundMember whfcl:WHFSTRSOhioSeniorLoanFundMember            
Investment, Type [Extensible Enumeration] whfcl:LLCInterestsMember whfcl:LLCInterestsMember whfcl:LLCInterestsMember whfcl:LLCInterestsMember whfcl:LLCInterestsMember   whfcl:LLCInterestsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Specialized Finance Specialized Finance Specialized Finance Specialized Finance Specialized Finance   Specialized Finance  
Acquisition Date Jul. 19, 2019 Jul. 19, 2019            
Investment owned shares | shares 21,104   21,104 21,104 21,104      
Principal/Share Amount   $ 21,104,000            
Investments, amortized cost $ 21,104,000 21,104,000            
Investments, fair value $ 21,602,000 $ 22,741,000            
Percent of net assets 8.30% 7.90% 8.30% 8.30% 8.30%   7.90%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Subordinated Note                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember            
Investment, Type [Extensible Enumeration] Subordinated Debt [Member] Subordinated Debt [Member] Subordinated Debt [Member] Subordinated Debt [Member] Subordinated Debt [Member]   Subordinated Debt [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Specialized Finance Specialized Finance Specialized Finance Specialized Finance Specialized Finance   Specialized Finance  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Spread Above Index 6.50% 6.50% 6.50% 6.50% 6.50%   6.50%  
Interest Rate 10.18% 10.83% 10.18% 10.18% 10.18%   10.83%  
Acquisition Date Jul. 19, 2019 Jul. 19, 2019            
Principal/Share Amount $ 84,416,000 $ 84,416,000            
Investments, amortized cost 84,416,000 84,416,000            
Investments, fair value $ 84,416,000 $ 84,416,000           $ 84,416,000
Percent of net assets 32.50% 29.50% 32.50% 32.50% 32.50%   29.50%  
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Delayed Draw Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Health Care Services Health Care Services Health Care Services Health Care Services Health Care Services   Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 9.92% 10.58% 9.92% 9.92% 9.92%   10.58%  
Acquisition Date Aug. 01, 2024 Aug. 01, 2024            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Investments, fair value $ 1,000 $ 2,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Health Care Services Health Care Services Health Care Services Health Care Services Health Care Services   Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 9.92% 10.58% 9.92% 9.92% 9.92%   10.58%  
Acquisition Date Aug. 01, 2024 Aug. 01, 2024            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Principal/Share Amount $ 345,000 $ 258,000            
Investments, amortized cost 340,000 253,000            
Investments, fair value $ 346,000 $ 254,000            
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10%   0.10%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Health Care Services Health Care Services Health Care Services Health Care Services Health Care Services   Health Care Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 6.25% 6.25% 6.25% 6.25% 6.25%   6.25%  
Interest Rate 9.92% 10.58% 9.92% 9.92% 9.92%   10.58%  
Acquisition Date Aug. 01, 2024 Aug. 01, 2024            
Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029   Aug. 01, 2029  
Principal/Share Amount $ 7,148,000 $ 7,689,000            
Investments, amortized cost 7,045,000 7,548,000            
Investments, fair value $ 7,100,000 $ 7,555,000            
Percent of net assets 2.70% 2.60% 2.70% 2.70% 2.70%   2.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: What If Media Group, LLC Common Units                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:WhatIfMediaGroupLLCMember whfcl:WhatIfMediaGroupLLCMember            
Investment, Type [Extensible Enumeration] whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember whfcl:CommonUnitsMember   whfcl:CommonUnitsMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Interactive Media & Services Interactive Media & Services Interactive Media & Services Interactive Media & Services Interactive Media & Services   Interactive Media & Services  
Acquisition Date Jul. 02, 2021 Jul. 02, 2021            
Investment owned shares | shares 3,081   3,081 3,081 3,081      
Principal/Share Amount   $ 3,081,000            
Investments, amortized cost $ 851,000 851,000            
Investments, fair value $ 1,963,000 $ 1,756,000            
Percent of net assets 0.80% 0.60% 0.80% 0.80% 0.80%   0.60%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Whitestone Home Furnishings, LLC (d/b/a Saatva, Inc.) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:WhitestoneHomeFurnishingsLlcMember whfcl:WhitestoneHomeFurnishingsLlcMember            
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Home Furnishings Home Furnishings Home Furnishings Home Furnishings Home Furnishings   Home Furnishings  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) One Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member] Secured Overnight Financing Rate (SOFR) One Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 1.00% 1.00% 1.00% 1.00% 1.00%   1.00%  
Spread Above Index 5.25% 6.00% 5.25% 5.25% 5.25%   6.00%  
Interest Rate 8.97% 10.46% 8.97% 8.97% 8.97%   10.46%  
Acquisition Date Nov. 06, 2023 Nov. 06, 2023            
Maturity Date Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026   Aug. 20, 2026  
Principal/Share Amount $ 2,848,000 $ 2,930,000            
Investments, amortized cost 2,832,000 2,887,000            
Investments, fair value $ 2,848,000 $ 2,930,000            
Percent of net assets 1.10% 1.00% 1.10% 1.10% 1.10%   1.00%  
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Zephyr Buyer, L.P. (d/b/a The Weather Company, LLC) First Lien Secured Revolving Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments  
Investment, Issuer Name [Extensible Enumeration] whfcl:ZephyrBuyerL.p.Member whfcl:ZephyrBuyerL.p.Member            
Investment, Type [Extensible Enumeration] whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember  
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember   srt:NorthAmericaMember  
Investment, Industry Sector [Extensible Enumeration] Interactive Media & Services Interactive Media & Services Interactive Media & Services Interactive Media & Services Interactive Media & Services   Interactive Media & Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] whfcl:SecuredOvernightFinancingRateMember Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   whfcl:SecuredOvernightFinancingRateMember  
Floor 0.50% 1.00% 0.50% 0.50% 0.50%   1.00%  
Spread Above Index 4.75% 6.50% 4.75% 4.75% 4.75%   6.50%  
Interest Rate 8.42% 10.83% 8.42% 8.42% 8.42%   10.83%  
Acquisition Date Jan. 31, 2024 Jan. 31, 2024            
Maturity Date Jan. 31, 2031 Jan. 31, 2030 Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031   Jan. 31, 2030  
Investments, fair value $ 32,000 $ 48,000            
Investment, Restriction Status [true false] true true true true true   true  
Investment, Significant Unobservable Input [true false] true true true true true   true  
Investment, Non-income Producing [true false] false false false false false   false  
Investment, Identifier [Axis]: Zephyr Buyer, L.P. (d/b/a The Weather Company, LLC) First Lien Secured Term Loan                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Name [Extensible Enumeration] whfcl:ZephyrBuyerL.p.Member              
Investment, Type [Extensible Enumeration] First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration] Interactive Media & Services   Interactive Media & Services Interactive Media & Services Interactive Media & Services      
Investment, Variable Interest Rate, Type [Extensible Enumeration] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]   Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member] Secured Overnight Financing Rate (SOFR) Three Month Term [Member]      
Floor 0.50%   0.50% 0.50% 0.50%      
Spread Above Index 4.75%   4.75% 4.75% 4.75%      
Interest Rate 8.42%   8.42% 8.42% 8.42%      
Acquisition Date Jan. 31, 2024              
Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031      
Principal/Share Amount $ 13,945,000              
Investments, amortized cost 13,701,000              
Investments, fair value $ 13,945,000              
Percent of net assets 5.40%   5.40% 5.40% 5.40%      
Investment, Restriction Status [true false] true   true true true      
Investment, Significant Unobservable Input [true false] true   true true true      
Investment, Non-income Producing [true false] false   false false false      
Morgan Stanley                
Schedule of Investments [Line Items]                
Unrealized appreciation   $ 20,000   € 2        
Unrealized depreciation $ (325,000)              
Morgan Stanley | CAD                
Schedule of Investments [Line Items]                
Currency to be sold 20,333 796            
Currency to be purchased   574            
Unrealized appreciation   $ 20,000            
Unrealized depreciation $ (325,000)              
Morgan Stanley | EUR                
Schedule of Investments [Line Items]                
Currency to be sold 4,989              
Currency to be purchased 5,874              
Morgan Stanley | USD                
Schedule of Investments [Line Items]                
Currency to be purchased 14,515 574            
Morgan Stanley One [Member]                
Schedule of Investments [Line Items]                
Unrealized appreciation $ 2,000              
Morgan Stanley One [Member] | EUR                
Schedule of Investments [Line Items]                
Currency to be sold 4,989              
Morgan Stanley One [Member] | USD                
Schedule of Investments [Line Items]                
Currency to be purchased 5,874              
Canadian Dollar Offered Rate Three Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 2.30%              
Prime Rate [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 6.80%              
Secured Overnight Financing Rate (SOFR) Three Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 3.70%              
Secured Overnight Financing Rate (SOFR) One Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 3.70%              
Secured Overnight Financing Rate (SOFR) Six Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 3.60%              
Canadian Overnight Repo Rate Average Three Months Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 2.30%              
Euro Interbank Offered Rate Three Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 2.00%              
Euro Interbank Offered Rate Six Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 2.10%              
Euro Interbank Offered Rate One Month Term [Member]                
Schedule of Investments [Line Items]                
Rate of interest on investment per duration period 1.90%              
Debt Investments                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 532,286,000 $ 631,941,000            
Investments, fair value $ 520,114,000 $ 596,626,000            
Percent of net assets 200.20% 208.40% 200.20% 200.20% 200.20%   208.40%  
Debt Investments | Advertising                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 1,191,000 $ 16,365,000            
Investments, fair value $ 1,196,000 $ 16,862,000            
Percent of net assets 0.50% 6.00% 0.50% 0.50% 0.50%   6.00%  
Debt Investments | Air Freight & Logistics                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 30,732,000 $ 29,360,000            
Investments, fair value $ 30,754,000 $ 28,518,000            
Percent of net assets 11.70% 9.90% 11.70% 11.70% 11.70%   9.90%  
Debt Investments | Application Software                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 22,062,000 $ 36,508,000            
Investments, fair value $ 20,888,000 $ 26,924,000            
Percent of net assets 8.00% 9.40% 8.00% 8.00% 8.00%   9.40%  
Debt Investments | Broadcasting                
Schedule of Investments [Line Items]                
Investments, amortized cost   $ 7,808,000            
Investments, fair value   $ 7,833,000            
Percent of net assets   2.70%         2.70%  
Debt Investments | Broadline Retail                
Schedule of Investments [Line Items]                
Investments, amortized cost   $ 4,556,000            
Investments, fair value   $ 4,580,000            
Percent of net assets   1.60%         1.60%  
Debt Investments | Building Products                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 14,957,000           $ 15,006  
Investments, fair value $ 13,748,000           $ 13,206  
Percent of net assets 5.30% 4.60% 5.30% 5.30% 5.30%   4.60%  
Debt Investments | Commodity Chemicals                
Schedule of Investments [Line Items]                
Investments, amortized cost   $ 15,765,000            
Investments, fair value   $ 16,026,000            
Percent of net assets   5.60%         5.60%  
Debt Investments | Human Resource & Employment Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 2,899,000              
Investments, fair value $ 2,909,000              
Percent of net assets 1.10%   1.10% 1.10% 1.10%      
Debt Investments | Construction & Engineering                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember         srt:NorthAmericaMember  
Investments, amortized cost $ 9,736,000 $ 3,539,000            
Investments, fair value $ 9,849,000 $ 3,539,000            
Percent of net assets 3.80% 1.20% 3.80% 3.80% 3.80%   1.20%  
Debt Investments | Construction Materials                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 5,684,000 $ 6,320,000            
Investments, fair value $ 5,159,000 $ 5,640,000            
Percent of net assets 2.00% 2.00% 2.00% 2.00% 2.00%   2.00%  
Debt Investments | Data Processing & Outsourced Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 26,661,000 $ 28,409,000            
Investments, fair value $ 26,789,000 $ 28,572,000            
Percent of net assets 10.30% 10.00% 10.30% 10.30% 10.30%   10.00%  
Debt Investments | Distributors                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 10,243,000 $ 10,563,000            
Investments, fair value $ 10,404,000 $ 10,690,000            
Percent of net assets 3.90% 3.70% 3.90% 3.90% 3.90%   3.70%  
Debt Investments | Diversified Chemicals                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 3,404,000 $ 3,342,000            
Investments, fair value $ 3,404,000 $ 3,342,000            
Percent of net assets 1.30% 1.20% 1.30% 1.30% 1.30%   1.20%  
Debt Investments | Diversified Support Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 9,440,000 $ 9,559,000            
Investments, fair value $ 9,337,000 $ 9,414,000            
Percent of net assets 3.60% 3.30% 3.60% 3.60% 3.60%   3.30%  
Debt Investments | Education Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 17,132,000 $ 22,584,000            
Investments, fair value $ 16,716,000 $ 21,214,000            
Percent of net assets 6.40% 7.40% 6.40% 6.40% 6.40%   7.40%  
Debt Investments | Electric Utilities                
Schedule of Investments [Line Items]                
Investments, amortized cost   $ 15,802,000            
Investments, fair value   $ 16,032,000            
Percent of net assets   5.60%         5.60%  
Debt Investments | Environmental & Facilities Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 1,568,000              
Investments, fair value $ 1,610,000              
Percent of net assets 0.70%   0.70% 0.70% 0.70%      
Debt Investments | Health Care Facilities                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 4,534,000 $ 8,694,000            
Investments, fair value $ 4,623,000 $ 8,660,000            
Percent of net assets 1.80% 3.00% 1.80% 1.80% 1.80%   3.00%  
Debt Investments | Health Care Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 8,315,000 $ 19,577,000            
Investments, fair value $ 8,389,000 $ 19,589,000            
Percent of net assets 3.20% 6.90% 3.20% 3.20% 3.20%   6.90%  
Debt Investments | Health Care Supplies                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 20,227,000 $ 20,142,000            
Investments, fair value $ 20,026,000 $ 19,535,000            
Percent of net assets 7.70% 6.80% 7.70% 7.70% 7.70%   6.80%  
Debt Investments | Heavy Electrical Equipment                
Schedule of Investments [Line Items]                
Investments, amortized cost   $ 9,971,000            
Investments, fair value   $ 10,138,000            
Percent of net assets   3.60%         3.60%  
Debt Investments | Home Furnishings                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 16,091,000 $ 25,288,000            
Investments, fair value $ 16,103,000 $ 25,376,000            
Percent of net assets 6.20% 8.80% 6.20% 6.20% 6.20%   8.80%  
Debt Investments | Household Products                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 11,400,000 $ 12,104,000            
Investments, fair value $ 9,658,000 $ 11,656,000            
Percent of net assets 3.70% 4.10% 3.70% 3.70% 3.70%   4.10%  
Debt Investments | Household Appliances                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 1,363,000 $ 22,326,000            
Investments, fair value $ 1,199,000 $ 21,255,000            
Percent of net assets 0.50% 7.40% 0.50% 0.50% 0.50%   7.40%  
Debt Investments | Industrial Machinery & Supplies & Components                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 12,154,000 $ 12,124,000            
Investments, fair value $ 12,334,000 $ 12,225,000            
Percent of net assets 4.70% 4.30% 4.70% 4.70% 4.70%   4.30%  
Debt Investments | Integrated Telecommunication Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 27,853,000 $ 12,602,000            
Investments, fair value $ 26,732,000 $ 13,135,000            
Percent of net assets 10.30% 4.60% 10.30% 10.30% 10.30%   4.60%  
Debt Investments | Interactive Media & Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 13,701,000 $ 13,789,000            
Investments, fair value $ 13,977,000 $ 14,214,000            
Percent of net assets 5.40% 5.00% 5.40% 5.40% 5.40%   5.00%  
Debt Investments | IT Consulting And Other Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 281,000              
Investments, fair value $ 300,000              
Percent of net assets 0.10%   0.10% 0.10% 0.10%      
Debt Investments | Leisure Facilities                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 20,332,000 $ 19,133,000            
Investments, fair value $ 14,521,000 $ 19,337,000            
Percent of net assets 5.70% 6.80% 5.70% 5.70% 5.70%   6.80%  
Debt Investments | Leisure Products                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 25,612,000 $ 45,674,000            
Investments, fair value $ 23,767,000 $ 23,298,000            
Percent of net assets 9.20% 8.10% 9.20% 9.20% 9.20%   8.10%  
Debt Investments | Oil & Gas Storage & Transportation                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 10,077,000              
Investments, fair value $ 10,158,000              
Percent of net assets 3.90%   3.90% 3.90% 3.90%      
Debt Investments | Life Sciences Tools & Services                
Schedule of Investments [Line Items]                
Investments, amortized cost   $ 4,953,000            
Investments, fair value   $ 5,000,000            
Percent of net assets   1.70%         1.70%  
Debt Investments | Packaged Foods & Meats                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 3,973,000 $ 4,024,000            
Investments, fair value $ 4,033,000 $ 4,087,000            
Percent of net assets 1.60% 1.40% 1.60% 1.60% 1.60%   1.40%  
Debt Investments | Paper Products                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 8,838,000 $ 9,119,000            
Investments, fair value $ 9,276,000 $ 9,453,000            
Percent of net assets 3.60% 3.30% 3.60% 3.60% 3.60%   3.30%  
Debt Investments | Pharmaceuticals                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 12,031,000              
Investments, fair value $ 12,027,000              
Percent of net assets 4.70%   4.70% 4.70% 4.70%      
Debt Investments | Real Estate Services                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investments, amortized cost $ 20,865,000 $ 21,016,000            
Investments, fair value $ 20,395,000 $ 20,710,000            
Percent of net assets 7.90% 7.30% 7.90% 7.90% 7.90%   7.30%  
Debt Investments | Research & Consulting Services                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investments, amortized cost $ 4,748,000 $ 4,823,000            
Investments, fair value $ 4,831,000 $ 4,927,000            
Percent of net assets 1.90% 1.70% 1.90% 1.90% 1.90%   1.70%  
Debt Investments | Specialized Consumer Services                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 18,925,000 $ 6,629,000            
Investments, fair value $ 18,993,000 $ 6,748,000            
Percent of net assets 7.20% 2.40% 7.20% 7.20% 7.20%   2.40%  
Debt Investments | Security & Alarm Services                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   Subordinated Debt [Member]         Subordinated Debt [Member]  
Investments, amortized cost   $ 6,857,000            
Investments, fair value   $ 7,070,000            
Percent of net assets   2.50%         2.50%  
Debt Investments | Specialized Finance                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 95,079,000 $ 84,416,000            
Investments, fair value $ 95,077,000 $ 84,416,000            
Percent of net assets 36.60% 29.50% 36.60% 36.60% 36.60%   29.50%  
Debt Investments | Systems Software                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 18,657,000 $ 16,573,000            
Investments, fair value $ 19,360,000 $ 17,267,000            
Percent of net assets 7.50% 5.90% 7.50% 7.50% 7.50%   5.90%  
Debt Investments | Technology Hardware, Storage & Peripherals                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]  
Investments, amortized cost $ 11,437,000 $ 18,547,000            
Investments, fair value $ 11,457,000 $ 18,072,000            
Percent of net assets 4.40% 6.30% 4.40% 4.40% 4.40%   6.30%  
Investment, Restriction Status [true false]   true         true  
Investment, Non-income Producing [true false]   false         false  
Debt Investments | Transaction & Payment Processing Services                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   whfcl:ClassBUnitsMember         whfcl:ClassBUnitsMember  
Investments, amortized cost $ 10,084,000 $ 8,074,000            
Investments, fair value $ 10,115,000 $ 8,066,000            
Percent of net assets 3.80% 2.80% 3.80% 3.80% 3.80%   2.80%  
Investment, Non-income Producing [true false]   false         false  
Subordinated Debt [Member]                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 1,269,000 $ 1,152,000            
Investments, fair value 1,286,000 1,175,000            
Equity Investments                
Schedule of Investments [Line Items]                
Investments, amortized cost 75,288,000 63,299,000            
Investments, fair value $ 58,535,000 $ 45,587,000            
Percent of net assets 22.50% 16.00% 22.50% 22.50% 22.50%   16.00%  
Equity Investments | Advertising                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Advertising         Advertising  
Investments, amortized cost $ 312,000 $ 297,000            
Investments, fair value $ 322,000 $ 589,000            
Percent of net assets 0.10% 0.20% 0.10% 0.10% 0.10%   0.20%  
Equity Investments | Air Freight & Logistics                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Air Freight & Logistics         Air Freight & Logistics  
Investments, amortized cost $ 1,250,000 $ 1,250,000            
Investments, fair value $ 774,000              
Percent of net assets 0.30%   0.30% 0.30% 0.30%      
Equity Investments | Application Software                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 1,682,000              
Investments, fair value $ 1,853,000              
Percent of net assets 0.70%   0.70% 0.70% 0.70%      
Equity Investments | Broadline Retail                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Broadline Retail         Broadline Retail  
Investments, amortized cost $ 514,000 $ 514,000            
Investments, fair value $ 735,000 $ 756,000            
Percent of net assets 0.30% 0.30% 0.30% 0.30% 0.30%   0.30%  
Equity Investments | Building Products                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   Warrant [Member]         Warrant [Member]  
Investment, Industry Sector [Extensible Enumeration]   Building Products         Building Products  
Investments, amortized cost $ 24,000 $ 24,000            
Equity Investments | Construction & Engineering                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Construction & Engineering         Construction & Engineering  
Investments, amortized cost 404,000 $ 404,000            
Investments, fair value 57,000 $ 388,000            
Percent of net assets   0.10%         0.10%  
Equity Investments | Diversified Chemicals                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Diversified Chemicals         Diversified Chemicals  
Investments, amortized cost 4,537,000 $ 4,537,000            
Investments, fair value $ 4,784,000 $ 1,657,000            
Percent of net assets 1.80% 0.60% 1.80% 1.80% 1.80%   0.60%  
Equity Investments | Diversified Support Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Diversified Support Services         Diversified Support Services  
Investments, amortized cost $ 385,000 $ 376,000            
Investments, fair value   $ 149,000            
Percent of net assets   0.10%         0.10%  
Equity Investments | Education Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Education Services         Education Services  
Investments, amortized cost 3,625,000 $ 334,000            
Investments, fair value $ 3,291,000 $ 100,000            
Percent of net assets 1.30%   1.30% 1.30% 1.30%      
Equity Investments | Environmental & Facilities Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Environmental & Facilities Services         Environmental & Facilities Services  
Investments, amortized cost $ 942,000 $ 942,000            
Investments, fair value $ 1,645,000 $ 1,400,000            
Percent of net assets 0.60% 0.50% 0.60% 0.60% 0.60%   0.50%  
Equity Investments | Food Distributors                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Food Distributors         Food Distributors  
Investments, amortized cost $ 317,000 $ 317,000            
Investments, fair value $ 264,000 $ 350,000            
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10%   0.10%  
Equity Investments | Household Appliances                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Household Appliances         Household Appliances  
Investments, amortized cost $ 1,100,000 $ 1,100,000            
Investments, fair value $ 1,003,000 $ 907,000            
Percent of net assets 0.40% 0.30% 0.40% 0.40% 0.40%   0.30%  
Equity Investments | Industrial Machinery & Supplies & Components                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration] Non-controlled/non-affiliate company investments   Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments Non-controlled/non-affiliate company investments      
Investment, Issuer Geographic Region [Extensible Enumeration] srt:NorthAmericaMember   srt:NorthAmericaMember srt:NorthAmericaMember srt:NorthAmericaMember      
Investment, Industry Sector [Extensible Enumeration]   Industrial Machinery & Supplies & Components         Industrial Machinery & Supplies & Components  
Investments, amortized cost $ 788,000 $ 788,000            
Investments, fair value $ 561,000 $ 1,012,000            
Percent of net assets 0.20% 0.40% 0.20% 0.20% 0.20%   0.40%  
Equity Investments | Interactive Media & Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Interactive Media & Services         Interactive Media & Services  
Investments, amortized cost $ 851,000 $ 851,000            
Investments, fair value $ 1,963,000 $ 1,756,000            
Percent of net assets 0.80% 0.60% 0.80% 0.80% 0.80%   0.60%  
Equity Investments | IT Consulting And Other Services                
Schedule of Investments [Line Items]                
Investment, Type [Extensible Enumeration]   Common Stock [Member]         Common Stock [Member]  
Investment, Industry Sector [Extensible Enumeration]   IT Consulting And Other Services         IT Consulting And Other Services  
Investments, amortized cost $ 1,612,000 $ 1,926,000            
Investments, fair value $ 987,000 $ 3,504,000            
Percent of net assets 0.40% 1.30% 0.40% 0.40% 0.40%   1.30%  
Investment, Restriction Status [true false]   true         true  
Equity Investments | Leisure Facilities                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Leisure Facilities         Leisure Facilities  
Investments, amortized cost $ 2,734,000 $ 2,734,000            
Investments, fair value $ 712,000 $ 243,000            
Percent of net assets 0.30% 0.10% 0.30% 0.30% 0.30%   0.10%  
Equity Investments | Leisure Products                
Schedule of Investments [Line Items]                
Investment, Issuer Affiliation [Extensible Enumeration]   Non-controlled/non-affiliate company investments         Non-controlled/non-affiliate company investments  
Investment, Type [Extensible Enumeration]   us-gaap:PreferredStockMember         us-gaap:PreferredStockMember  
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investments, amortized cost $ 4,060,000 $ 4,060,000            
Equity Investments | Paper & Plastic Packaging Products & Materials                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Leisure Products         Leisure Products  
Investments, amortized cost 400,000 $ 400,000            
Equity Investments | Real Estate Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Real Estate Services [Member]         Real Estate Services [Member]  
Investments, amortized cost 840,000 $ 840,000            
Investments, fair value 31,000 $ 162,000            
Percent of net assets   0.10%         0.10%  
Equity Investments | Research & Consulting Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Research & Consulting Services         Research & Consulting Services  
Investments, amortized cost 333,000 $ 333,000            
Investments, fair value $ 312,000 $ 368,000            
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10%   0.10%  
Equity Investments | Specialized Consumer Services                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Specialized Consumer Services         Specialized Consumer Services  
Investments, amortized cost $ 797,000 $ 600,000            
Investments, fair value $ 468,000 $ 374,000            
Percent of net assets 0.20% 0.10% 0.20% 0.20% 0.20%   0.10%  
Equity Investments | Specialized Finance                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Specialized Finance         Specialized Finance  
Investments, amortized cost $ 21,104,000 $ 21,104,000            
Investments, fair value $ 21,602,000 $ 22,741,000            
Percent of net assets 8.30% 7.90% 8.30% 8.30% 8.30%   7.90%  
Equity Investments | Systems Software                
Schedule of Investments [Line Items]                
Investment, Industry Sector [Extensible Enumeration]   Systems Software         Systems Software  
Investments, amortized cost $ 19,568,000 $ 19,568,000            
Investments, fair value $ 9,144,000 $ 9,131,000            
Percent of net assets 3.50% 3.20% 3.50% 3.50% 3.50%   3.20%  
Equity Investments | Technology Hardware, Storage & Peripherals                
Schedule of Investments [Line Items]                
Investments, amortized cost $ 7,109,000              
Investments, fair value $ 8,027,000              
Percent of net assets 3.10%   3.10% 3.10% 3.10%      
Money Market Funds                
Schedule of Investments [Line Items]                
Percent of net assets 8.10% 4.60% 8.10% 8.10% 8.10%   4.60%  
Money Market Funds amortized cost $ 21,048,000 $ 13,249,000            
Money Market Fair Value $ 21,048,000 $ 13,249,000            
Goldman Sachs Money Market Fund (CUSIP: 38141W315)                
Schedule of Investments [Line Items]                
Percent of net assets 3.40% 0.30% 3.40% 3.40% 3.40%   0.30%  
Weighted average interest rate 3.34% 4.33% 3.34% 3.34% 3.34%   4.33%  
Money Market Funds amortized cost $ 8,829,000 $ 837,000            
Money Market Fair Value $ 8,829,000 $ 837,000            
Invesco Treasury Money Market Fund (CUSIP: 825252406)                
Schedule of Investments [Line Items]                
Percent of net assets 2.70% 4.30% 2.70% 2.70% 2.70%   4.30%  
Weighted average interest rate 3.09% 3.83% 3.09% 3.09% 3.09%   3.83%  
Money Market Funds amortized cost $ 7,032,000 $ 12,412,000            
Money Market Fair Value $ 7,032,000 12,412,000            
Dreyfus Treasury Obligations Cash Management Fund (CUSIP: 261908107)                
Schedule of Investments [Line Items]                
Percent of net assets 2.00%   2.00% 2.00% 2.00%      
Weighted average interest rate 3.65%   3.65% 3.65% 3.65%      
Money Market Funds amortized cost $ 5,187,000              
Alvaria Holdco [Member] | First Lien Secured Term Loan [Member]                
Schedule of Investments [Line Items]                
Investments, amortized cost           $ 1,682,000    
Non-controlled/non-affiliate company investments                
Schedule of Investments [Line Items]                
Investments, fair value $ 436,589,000 $ 504,832,000