v3.25.4
INVESTMENTS - STRS JVs individual Investments (Details)
€ 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 ($)
shares
Dec. 31, 2025
EUR (€)
shares
Dec. 31, 2025
GBP (£)
shares
Dec. 31, 2024
CAD ($)
shares
Dec. 31, 2023
USD ($)
Schedule of Investments [Line Items]              
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  
Investment Owned, at Cost $ 607,574,000 $ 695,240,000          
Investment Owned, at Fair Value 578,649,000 $ 642,213,000          
Money Market Fair Value $ 5,187,000            
Percent of net assets 222.70% 224.40% 222.70% 222.70% 222.70% 224.40%  
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%  
STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 323,601,000 $ 296,752,000          
Investments owned non-accrual status 0 0          
Investment Owned, at Fair Value $ 323,552,000 $ 294,957,000          
Fair Value As A Percentage of Member's Equity 984.30% 852.30%          
Percent of net assets 984.30% 852.30% 984.30% 984.30% 984.30% 852.30%  
Total investments and money market funds amortized cost $ 329,483,000 $ 297,519,000          
Total investments and money market funds fair value $ 329,434,000 $ 295,724,000          
Total investments and money market funds percentage 1002.20% 854.50% 1002.20% 1002.20% 1002.20% 854.50%  
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) Three 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%            
Prime Rate [Member]              
Schedule of Investments [Line Items]              
Rate of interest on investment per duration period 6.80%            
Canadian Dollar Offered Rate Three Month Term [Member]              
Schedule of Investments [Line Items]              
Rate of interest on investment per duration period 2.30%            
Euro Interbank Offered Rate One Month Term [Member]              
Schedule of Investments [Line Items]              
Rate of interest on investment per duration period 1.90%            
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%            
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]  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   5.25%       5.25%  
Investment Interest Rate   9.78%       9.78%  
Investment, Acquisition Date   Sep. 19, 2024          
Investment Maturity Date   Jul. 02, 2031       Jul. 02, 2031  
Investment Owned, Balance, Principal Amount   $ 78,000          
Investment Owned, at Cost   78,000          
Investment Owned, at Fair Value   $ 80,000          
Fair Value As A Percentage of Member's Equity   0.20%          
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]  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   5.25%       5.25%  
Investment Interest Rate   9.78%       9.78%  
Investment, Acquisition Date   Sep. 19, 2024          
Investment Maturity Date   Jul. 02, 2031       Jul. 02, 2031  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   5.25%       5.25%  
Investment Interest Rate   9.79%       9.79%  
Investment, Acquisition Date   Sep. 19, 2024          
Investment Maturity Date   Jul. 02, 2031       Jul. 02, 2031  
Investment Owned, Balance, Principal Amount   $ 7,962,000          
Investment Owned, at Cost   7,866,000          
Investment Owned, at Fair Value   $ 7,919,000          
Fair Value As A Percentage of Member's Equity   22.90%          
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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 5.25%   5.25% 5.25% 5.25%    
Investment Interest Rate 8.97%   8.97% 8.97% 8.97%    
Investment, Acquisition Date Sep. 19, 2024            
Investment Maturity Date Jul. 02, 2031   Jul. 02, 2031 Jul. 02, 2031 Jul. 02, 2031    
Investment Owned, Balance, Principal Amount $ 408,000            
Investment Owned, at Cost 405,000            
Investment Owned, at Fair Value $ 409,000            
Fair Value As A Percentage of Member's Equity 1.20%            
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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 5.25%   5.25% 5.25% 5.25%    
Investment Interest Rate 8.97%   8.97% 8.97% 8.97%    
Investment, Acquisition Date Sep. 19, 2024            
Investment Maturity Date Jul. 02, 2031   Jul. 02, 2031 Jul. 02, 2031 Jul. 02, 2031    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 5.25%   5.25% 5.25% 5.25%    
Investment Interest Rate 8.97%   8.97% 8.97% 8.97%    
Investment, Acquisition Date Sep. 19, 2024            
Investment Maturity Date Jul. 02, 2031   Jul. 02, 2031 Jul. 02, 2031 Jul. 02, 2031    
Investment Owned, Balance, Principal Amount $ 13,039,000            
Investment Owned, at Cost 12,922,000            
Investment Owned, at Fair Value $ 12,973,000            
Fair Value As A Percentage of Member's Equity 39.50%            
Investment, Identifier [Axis]: ABB/Con-cise Optical Group LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.34% 11.98% 11.34% 11.34% 11.34% 11.98%  
Investment, Acquisition Date Feb. 23, 2022 Feb. 23, 2022          
Investment Maturity Date Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028 Feb. 23, 2028  
Investment Owned, Balance, Principal Amount $ 20,409,000 $ 20,409,000          
Investment Owned, at Cost 20,227,000 20,142,000          
Investment Owned, at 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, 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.40%       10.40%  
Investment, Acquisition Date   Apr. 26, 2024          
Investment Maturity Date   Apr. 16, 2030       Apr. 16, 2030  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.40%       10.40%  
Investment, Acquisition Date   Apr. 26, 2024          
Investment Maturity Date   Apr. 16, 2030       Apr. 16, 2030  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.40%       10.40%  
Investment, Acquisition Date   Apr. 26, 2024          
Investment Maturity Date   Apr. 16, 2030       Apr. 16, 2030  
Investment Owned, Balance, Principal Amount   $ 4,080,000          
Investment Owned, at Cost   4,027,000          
Investment Owned, at Fair Value   $ 4,070,000          
Fair Value As A Percentage of Member's Equity   11.80%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.39%   9.39% 9.39% 9.39%    
Investment, Acquisition Date Apr. 26, 2024            
Investment Maturity Date Apr. 16, 2030   Apr. 16, 2030 Apr. 16, 2030 Apr. 16, 2030    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.39%   9.39% 9.39% 9.39%    
Investment, Acquisition Date Apr. 26, 2024            
Investment Maturity Date Apr. 16, 2030   Apr. 16, 2030 Apr. 16, 2030 Apr. 16, 2030    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.39%   9.39% 9.39% 9.39%    
Investment, Acquisition Date Apr. 26, 2024            
Investment Maturity Date Apr. 16, 2030   Apr. 16, 2030 Apr. 16, 2030 Apr. 16, 2030    
Investment Owned, Balance, Principal Amount $ 4,046,000            
Investment Owned, at Cost 4,002,000            
Investment Owned, at Fair Value $ 4,046,000            
Fair Value As A Percentage of Member's Equity 12.30%            
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   7.50%       7.50%  
Investment Interest Rate   11.96%       11.96%  
Investment, Acquisition Date   Mar. 20, 2024          
Investment Maturity Date   May 08, 2028       May 08, 2028  
Investment Owned, Balance, Principal Amount   $ 1,782,000          
Investment Owned, at Cost   1,615,000          
Investment Owned, at Fair Value   $ 1,456,000          
Investment, Interest Rate, Paid in Kind   6.50%       6.50%  
Investment, Interest Rate, Paid in Cash   5.46%       5.46%  
Percent of net assets   0.50%       0.50%  
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 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  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   7.00%       7.00%  
Investment Interest Rate   11.46%       11.46%  
Investment, Acquisition Date   Mar. 20, 2024          
Investment Maturity Date   May 08, 2028       May 08, 2028  
Investment Owned, Balance, Principal Amount   $ 9,600,000          
Investment Owned, at Cost   9,318,000          
Investment Owned, at Fair Value   $ 3,990,000          
Percent of net assets   1.40%       1.40%  
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 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  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   7.50%       7.50%  
Investment Interest Rate   11.96%       11.96%  
Investment, Acquisition Date   Mar. 20, 2024          
Investment Maturity Date   May 08, 2028       May 08, 2028  
Investment Owned, Balance, Principal Amount   $ 1,178,000          
Investment Owned, at Cost   1,029,000          
Investment Owned, at Fair Value   $ 451,000          
Investment, Interest Rate, Paid in Kind   5.50%       5.50%  
Investment, Interest Rate, Paid in Cash   6.46%       6.46%  
Percent of net assets   0.20%       0.20%  
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 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  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   7.00%       7.00%  
Investment Interest Rate   11.46%       11.46%  
Investment, Acquisition Date   Mar. 20, 2024          
Investment Maturity Date   May 08, 2028       May 08, 2028  
Investment Owned, Balance, Principal Amount   $ 2,400,000          
Investment Owned, at Cost   2,330,000          
Investment Owned, at Fair Value   $ 74,000          
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  
Investment, Acquisition Date   Dec. 22, 2022          
Investment Maturity Date   Dec. 22, 2032       Dec. 22, 2032  
Investment, Identifier [Axis]: American Crafts Lc Super Priority First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.50%       8.50%  
Investment, Acquisition Date   Jul. 25, 2023          
Investment Maturity Date   May 28, 2026       May 28, 2026  
Investment Owned, Balance, Principal Amount   $ 2,191,000          
Investment Owned, at Cost   $ 2,094,000          
Investment Owned, at Fair Value             $ 1,878,000
Investment, Interest Rate, Paid in Kind   12.96%       12.96%  
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Investment Interest Rate   8.50%       8.50%  
Investment, Acquisition Date   Jan. 25, 2022          
Investment Maturity Date   May 28, 2026       May 28, 2026  
Investment Owned, Balance, Principal Amount   $ 1,823,000          
Investment Owned, at Cost   $ 1,458,000          
Investment Owned, at Fair Value             93,000
Investment, Interest Rate, Paid in Kind   12.96%       12.96%  
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Investment Interest Rate   8.50%       8.50%  
Investment, Acquisition Date   May 28, 2021          
Investment Maturity Date   May 28, 2026       May 28, 2026  
Investment Owned, Balance, Principal Amount   $ 10,859,000          
Investment Owned, at Cost   $ 8,720,000          
Investment Owned, at Fair Value             553,000
Investment, Interest Rate, Paid in Kind   12.96%       12.96%  
Investment, Identifier [Axis]: American Crafts, LC Priority First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.50%       8.50%  
Investment, Acquisition Date   Dec. 22, 2022          
Investment Maturity Date   May 28, 2026       May 28, 2026  
Investment Owned, Balance, Principal Amount   $ 5,876,000          
Investment Owned, at Cost   $ 5,105,000          
Investment Owned, at Fair Value             3,226,000
Investment, Interest Rate, Paid in Kind   12.96%       12.96%  
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.50%       8.50%  
Investment, Acquisition Date   May 02, 2024          
Investment Maturity Date   May 28, 2026       May 28, 2026  
Investment Owned, Balance, Principal Amount   $ 2,485,000          
Investment Owned, at Cost   2,374,000          
Investment Owned, at Fair Value   $ 373,000          
Investment, Interest Rate, Paid in Kind   12.96%       12.96%  
Percent of net assets   0.10%       0.10%  
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan one              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.50%       8.50%  
Investment, Acquisition Date   Jan. 31, 2024          
Investment Maturity Date   May 28, 2026       May 28, 2026  
Investment Owned, Balance, Principal Amount   $ 1,287,000          
Investment Owned, at Cost   $ 1,230,000          
Investment, Interest Rate, Paid in Kind   12.96%       12.96%  
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.33%   9.33% 9.33% 9.33%    
Investment, Acquisition Date Jul. 21, 2025            
Investment Maturity Date Jun. 18, 2032   Jun. 18, 2032 Jun. 18, 2032 Jun. 18, 2032    
Investment Owned, Balance, Principal Amount $ 2,372,000            
Investment Owned, at Cost 2,339,000            
Investment Owned, at Fair Value $ 2,442,000            
Fair Value As A Percentage of Member's Equity 7.40%            
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.37%   9.37% 9.37% 9.37%    
Investment, Acquisition Date Jul. 21, 2025            
Investment Maturity Date Jun. 18, 2032   Jun. 18, 2032 Jun. 18, 2032 Jun. 18, 2032    
Investment Owned, Balance, Principal Amount $ 6,633,000            
Investment Owned, at Cost 6,542,000            
Investment Owned, at Fair Value $ 6,632,000            
Fair Value As A Percentage of Member's Equity 20.20%            
Investment, Identifier [Axis]: Arcserve Cayman GP LLC (d/b/a Arcserve (USA), LLC) Common Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Jan. 03, 2024 Jan. 03, 2024          
Investment Owned, Balance, Shares | shares 663   663 663 663    
Investment Owned, Balance, Principal Amount   $ 663,000          
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 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  
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 8.00% 8.00% 8.00% 8.00% 8.00% 8.00%  
Investment, Acquisition Date Jan. 03, 2024 Jan. 03, 2024          
Investment Maturity Date Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027 Jan. 04, 2027  
Investment Owned, Balance, Principal Amount $ 781,000 $ 689,000          
Investment Owned, at Cost 775,000 677,000          
Investment Owned, at Fair Value $ 1,240,000 $ 1,247,000          
Investment, Interest Rate, Paid in Kind 11.99% 12.67% 11.99% 11.99% 11.99% 12.67%  
Percent of net assets 0.50% 0.40% 0.50% 0.50% 0.50% 0.40%  
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) Unsecured Loan One              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Jan. 03, 2024 Jan. 03, 2024          
Investment Maturity Date Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029  
Investment Owned, Balance, Principal Amount $ 636,000 $ 581,000          
Investment Owned, at Cost 627,000 569,000          
Investment Owned, at Fair Value $ 636,000 $ 581,000          
Investment, Interest Rate, Paid in Kind 9.00% 9.00% 9.00% 9.00% 9.00% 9.00%  
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%  
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) Unsecured Loan Two              
Schedule of Investments [Line Items]              
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  
Investment Interest Rate 9.00%   9.00% 9.00% 9.00%    
Investment, Acquisition Date Jan. 03, 2024 Jan. 03, 2024          
Investment Maturity Date Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029 Jul. 02, 2029  
Investment Owned, Balance, Principal Amount $ 650,000 $ 594,000          
Investment Owned, at Cost 642,000 583,000          
Investment Owned, at Fair Value $ 650,000 $ 594,000          
Investment, Interest Rate, Paid in Kind   9.00%       9.00%  
Percent of net assets 0.30% 0.20% 0.30% 0.30% 0.30% 0.20%  
Investment, Identifier [Axis]: Arcserve Cayman Topco LP (d/b/a Arcserve (USA), LLC) Common Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Jan. 03, 2024 Jan. 03, 2024          
Investment Owned, Balance, Shares | shares 663   663 663 663    
Investment Owned, Balance, Principal Amount   $ 663,000          
Investment Owned, at Cost $ 19,568,000 19,568,000          
Investment Owned, at 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, 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    
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.00%       5.00%  
Investment Interest Rate   9.33%       9.33%  
Investment, Acquisition Date   Oct. 25, 2023          
Investment Maturity Date   Oct. 18, 2028       Oct. 18, 2028  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.00%       5.00%  
Investment Interest Rate   9.33%       9.33%  
Investment, Acquisition Date   Oct. 25, 2023          
Investment Maturity Date   Oct. 18, 2028       Oct. 18, 2028  
Investment Owned, Balance, Principal Amount   $ 4,972,000          
Investment Owned, at Cost   4,877,000          
Investment Owned, at Fair Value   $ 5,021,000          
Fair Value As A Percentage of Member's Equity   14.50%          
Investment, Identifier [Axis]: Atlas Parent, LLC Common Units              
Schedule of Investments [Line Items]              
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    
Investment, Acquisition Date Oct. 24, 2025            
Investment Owned, Balance, Principal Amount $ 19,000            
Investment Owned, at Cost 1,682,000            
Investment Owned, at Fair Value $ 1,853,000            
Percent of net assets 0.70%   0.70% 0.70% 0.70%    
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.82% 10.48% 9.82% 9.82% 9.82% 10.48%  
Investment, Acquisition Date May 31, 2024 May 31, 2024          
Investment Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026  
Investment Owned, Balance, Principal Amount $ 548,000 $ 553,000          
Investment Owned, at Cost 544,000 545,000          
Investment Owned, at Fair Value $ 546,000 $ 558,000          
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%  
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.82% 10.48% 9.82% 9.82% 9.82% 10.48%  
Investment, Acquisition Date May 31, 2024 May 31, 2024          
Investment Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026  
Investment Owned, Balance, Principal Amount $ 652,000 $ 658,000          
Investment Owned, at Cost 647,000 648,000          
Investment Owned, at Fair Value $ 650,000 $ 652,000          
Percent of net assets 0.30% 0.20% 0.30% 0.30% 0.30% 0.20%  
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group), Class A LLC Interests              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date   Dec. 15, 2021          
Investment Owned, Balance, Shares | shares   200       200  
Investment Owned, at Cost   $ 287,000          
Investment Owned, at Fair Value   $ 577,000          
Percent of net assets   0.20%       0.20%  
Investment, Identifier [Axis]: Avision Holdings, LLC Class A LLC Interests              
Schedule of Investments [Line Items]              
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    
Investment, Acquisition Date Dec. 15, 2021            
Investment Owned, Balance, Shares | shares 299   299 299 299    
Investment Owned, at Cost $ 299,000            
Investment Owned, at Fair Value $ 322,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.50%       1.50%  
Spread Above Index   10.50%       10.50%  
Investment Interest Rate   14.96%       14.96%  
Investment, Acquisition Date   Dec. 02, 2021          
Investment Maturity Date   Aug. 28, 2025       Aug. 28, 2025  
Investment Owned, Balance, Principal Amount   $ 2,654,000          
Investment Owned, at Cost   2,645,000          
Investment Owned, at Fair Value   $ 2,642,000          
Investment, Interest Rate, Paid in Kind   2.00%       2.00%  
Investment, Interest Rate, Paid in Cash   12.96%       12.96%  
Percent of net assets   0.90%       0.90%  
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.50%       1.50%  
Spread Above Index   10.50%       10.50%  
Investment Interest Rate   14.96%       14.96%  
Investment, Acquisition Date   Aug. 28, 2020          
Investment Maturity Date   Aug. 28, 2025       Aug. 28, 2025  
Investment Owned, Balance, Principal Amount   $ 13,013,000          
Investment Owned, at Cost   12,972,000          
Investment Owned, at Fair Value   $ 12,955,000          
Investment, Interest Rate, Paid in Kind   2.00%       2.00%  
Investment, Interest Rate, Paid in Cash   12.96%       12.96%  
Percent of net assets   4.50%       4.50%  
Investment, Identifier [Axis]: BBQ Buyer, LLC Shares              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Aug. 28, 2020 Aug. 28, 2020          
Investment Owned, Balance, Shares | shares 1,100   1,100 1,100 1,100    
Investment Owned, Balance, Principal Amount   $ 1,100,000          
Investment Owned, at Cost $ 1,100,000 1,100,000          
Investment Owned, at Fair Value $ 1,003,000 $ 907,000          
Percent of net assets 0.40% 0.30% 0.40% 0.40% 0.40% 0.30%  
Investment, Identifier [Axis]: BL Products Parent, LP Class A Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Feb. 01, 2022 Feb. 01, 2022          
Investment Owned, Balance, Shares | shares 733   733 733 733    
Investment Owned, Balance, Principal Amount   $ 733,000          
Investment Owned, at Cost $ 788,000 788,000          
Investment Owned, at Fair Value $ 561,000 $ 1,012,000          
Percent of net assets 0.20% 0.40% 0.20% 0.20% 0.20% 0.40%  
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 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  
Investment, Acquisition Date   Dec. 29, 2021          
Investment Owned, Balance, Principal Amount   $ 90,000          
Investment Owned, at Cost   942,000          
Investment Owned, at Fair Value   $ 1,400,000          
Percent of net assets   0.50%       0.50%  
Investment, Identifier [Axis]: BPII-JL Group Holdings LP Class A Units              
Schedule of Investments [Line Items]              
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    
Investment, Acquisition Date Dec. 29, 2021            
Investment Owned, Balance, Shares | shares 90   90 90 90    
Investment Owned, at Cost $ 942,000            
Investment Owned, at Fair Value $ 1,645,000            
Percent of net assets 0.60%   0.60% 0.60% 0.60%    
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.34% 10.81% 10.34% 10.34% 10.34% 10.81%  
Investment, Acquisition Date Apr. 04, 2024 Apr. 04, 2024          
Investment Maturity Date Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029  
Investment Owned, Balance, Principal Amount $ 276,000 $ 459,000          
Investment Owned, at Cost 270,000 447,000          
Investment Owned, at Fair Value $ 283,000 $ 461,000          
Percent of net assets 0.10% 0.20% 0.10% 0.10% 0.10% 0.20%  
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.29% 10.77% 10.29% 10.29% 10.29% 10.77%  
Investment, Acquisition Date Apr. 04, 2024 Apr. 04, 2024          
Investment Maturity Date Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029 Mar. 30, 2029  
Investment Owned, Balance, Principal Amount $ 7,374,000 $ 7,779,000          
Investment Owned, at Cost 7,231,000 7,580,000          
Investment Owned, at 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, 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.07% 10.59% 10.07% 10.07% 10.07% 10.59%  
Investment, Acquisition Date Dec. 21, 2023 Dec. 21, 2023          
Investment Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029  
Investment Owned, Balance, Principal Amount $ 1,873,000 $ 1,502,000          
Investment Owned, at Cost 1,845,000 1,472,000          
Investment Owned, at Fair Value $ 1,766,000 $ 1,477,000          
Fair Value As A Percentage of Member's Equity 5.40% 4.30%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.07% 10.61% 10.07% 10.07% 10.07% 10.61%  
Investment, Acquisition Date Dec. 21, 2023 Dec. 21, 2023          
Investment Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029  
Investment Owned, Balance, Principal Amount $ 168,000 $ 420,000          
Investment Owned, at Cost 166,000 412,000          
Investment Owned, at Fair Value $ 118,000 $ 415,000          
Fair Value As A Percentage of Member's Equity 0.40% 1.20%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.07% 10.61% 10.07% 10.07% 10.07% 10.61%  
Investment, Acquisition Date Dec. 21, 2023 Dec. 21, 2023          
Investment Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029  
Investment Owned, Balance, Principal Amount $ 2,956,000 $ 3,033,000          
Investment Owned, at Cost 2,912,000 2,974,000          
Investment Owned, at Fair Value $ 2,787,000 $ 2,981,000          
Fair Value As A Percentage of Member's Equity 8.40% 8.60%          
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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 5.92%   5.92% 5.92% 5.92%    
Investment Interest Rate 10.02%   10.02% 10.02% 10.02%    
Investment, Acquisition Date Jan. 10, 2024            
Investment Maturity Date Nov. 21, 2028   Nov. 21, 2028 Nov. 21, 2028 Nov. 21, 2028    
Investment Owned, Balance, Principal Amount $ 373,000            
Investment Owned, at Cost 367,000            
Investment Owned, at Fair Value $ 366,000            
Fair Value As A Percentage of Member's Equity 1.10%            
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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.82%   9.82% 9.82% 9.82%    
Investment, Acquisition Date Jan. 10, 2024            
Investment Maturity Date Nov. 21, 2029   Nov. 21, 2029 Nov. 21, 2029 Nov. 21, 2029    
Investment Owned, Balance, Principal Amount $ 3,580,000            
Investment Owned, at Cost 3,523,000            
Investment Owned, at Fair Value $ 3,493,000            
Fair Value As A Percentage of Member's Equity 10.60%            
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]  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   10.51%       10.51%  
Investment, Acquisition Date   Jan. 10, 2024          
Investment Maturity Date   Nov. 21, 2029       Nov. 21, 2029  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   5.00%       5.00%  
Investment Interest Rate   12.50%       12.50%  
Investment, Acquisition Date   Jan. 10, 2024          
Investment Maturity Date   Nov. 21, 2028       Nov. 21, 2028  
Investment Owned, Balance, Principal Amount   $ 60,000          
Investment Owned, at Cost   58,000          
Investment Owned, at Fair Value   $ 63,000          
Fair Value As A Percentage of Member's Equity   0.20%          
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]  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   10.51%       10.51%  
Investment, Acquisition Date   Jan. 10, 2024          
Investment Maturity Date   Nov. 21, 2029       Nov. 21, 2029  
Investment Owned, Balance, Principal Amount   $ 3,617,000          
Investment Owned, at Cost   3,543,000          
Investment Owned, at Fair Value   $ 3,574,000          
Fair Value As A Percentage of Member's Equity   10.30%          
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 & Defense       Aerospace & Defense  
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.50%       5.50%  
Investment Interest Rate   9.94%       9.94%  
Investment, Acquisition Date   Sep. 13, 2024          
Investment Maturity Date   Dec. 05, 2028       Dec. 05, 2028  
Investment Owned, at 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 & Defense       Aerospace & Defense  
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.50%       5.50%  
Investment Interest Rate   9.94%       9.94%  
Investment, Acquisition Date   Sep. 13, 2024          
Investment Maturity Date   Dec. 05, 2028       Dec. 05, 2028  
Investment Owned, Balance, Principal Amount   $ 3,681,000          
Investment Owned, at Cost   3,633,000          
Investment Owned, at Fair Value   $ 3,675,000          
Fair Value As A Percentage of Member's Equity   10.60%          
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.46%       12.46%  
Investment, Acquisition Date   Oct. 05, 2021          
Investment Maturity Date   Oct. 05, 2026       Oct. 05, 2026  
Investment Owned, Balance, Principal Amount   $ 238,000          
Investment Owned, at Cost   237,000          
Investment Owned, at Fair Value   $ 231,000          
Percent of net assets   0.10%       0.10%  
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.46%       12.46%  
Investment, Acquisition Date   Oct. 05, 2021          
Investment Maturity Date   Oct. 05, 2026       Oct. 05, 2026  
Investment Owned, Balance, Principal Amount   $ 8,517,000          
Investment Owned, at Cost   8,457,000          
Investment Owned, at Fair Value   $ 8,429,000          
Percent of net assets   2.90%       2.90%  
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 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Dec. 17, 2025            
Investment Maturity Date Aug. 01, 2029   Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029    
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.26% 8.45% 10.26% 10.26% 10.26% 8.45%  
Investment, Acquisition Date Aug. 09, 2023 Aug. 09, 2023          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, Balance, Principal Amount $ 2,319,000 $ 2,168,000          
Investment Owned, at Cost 2,281,000 2,120,000          
Investment Owned, at Fair Value $ 2,323,000 $ 2,183,000          
Fair Value As A Percentage of Member's Equity 7.10% 6.30%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.32% 10.96% 10.32% 10.32% 10.32% 10.96%  
Investment, Acquisition Date Aug. 09, 2023 Aug. 09, 2023          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, Balance, Principal Amount $ 370,000 $ 234,000          
Investment Owned, at Cost 365,000 230,000          
Investment Owned, at Fair Value $ 379,000 $ 248,000          
Fair Value As A Percentage of Member's Equity 1.20% 0.70%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.23% 10.88% 10.23% 10.23% 10.23% 10.88%  
Investment, Acquisition Date Aug. 09, 2023 Aug. 09, 2023          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, Balance, Principal Amount $ 6,834,000 $ 6,904,000          
Investment Owned, at Cost 6,733,000 6,774,000          
Investment Owned, at Fair Value $ 6,834,000 $ 6,952,000          
Fair Value As A Percentage of Member's Equity 20.80% 20.10%          
Investment, Identifier [Axis]: CX Holdco LLC Common Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date May 04, 2021 May 04, 2021          
Investment Owned, Balance, Shares | shares 1,068   1,068 1,068 1,068    
Investment Owned, Balance, Principal Amount   $ 1,068,000          
Investment Owned, at Cost $ 1,116,000 1,116,000          
Investment Owned, at Fair Value $ 218,000 $ 2,232,000          
Percent of net assets 0.10% 0.80% 0.10% 0.10% 0.10% 0.80%  
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 [Member]   Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]    
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 8.50%   8.50% 8.50% 8.50%    
Investment, Acquisition Date Jan. 10, 2025            
Investment Maturity Date Sep. 25, 2029   Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029    
Investment Owned, Balance, Principal Amount $ 1,218,000            
Investment Owned, at Cost 1,135,000            
Investment Owned, at Fair Value $ 196,000            
Investment, Interest Rate, Paid in Kind 12.83%   12.83% 12.83% 12.83%    
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [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  
Investment, Interest Rate, 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%  
Investment, Acquisition Date Sep. 25, 2024 Sep. 25, 2024          
Investment Maturity Date Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029 Sep. 25, 2029  
Investment Owned, Balance, Principal Amount $ 13,370,000 $ 11,738,000          
Investment Owned, at Cost 10,231,000 10,269,000          
Investment Owned, at Fair Value $ 5,354,000 $ 10,492,000          
Investment, Interest Rate, Paid in Kind 12.32% 12.98% 12.32% 12.32% 12.32% 12.98%  
Percent of net assets 2.10% 3.70% 2.10% 2.10% 2.10% 3.70%  
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 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       Real Estate Services  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Nov. 16, 2021          
Investment Maturity Date   Nov. 16, 2027       Nov. 16, 2027  
Investment Owned, Balance, Principal Amount   $ 10,424,000          
Investment Owned, at Cost   10,325,000          
Investment Owned, at Fair Value   $ 9,905,000          
Percent of net assets   3.50%       3.50%  
Investment, Identifier [Axis]: Camp Facility Services Holdings, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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   Real Estate Services Real Estate Services Real Estate 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Nov. 16, 2021            
Investment Maturity Date Nov. 16, 2027   Nov. 16, 2027 Nov. 16, 2027 Nov. 16, 2027    
Investment Owned, Balance, Principal Amount $ 10,294,000            
Investment Owned, at Cost 10,230,000            
Investment Owned, at Fair Value $ 9,781,000            
Percent of net assets 3.80%   3.80% 3.80% 3.80%    
Investment, Identifier [Axis]: Camp Facility Services Parent, LLC Preferred Units              
Schedule of Investments [Line Items]              
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 Real Estate Services Real Estate Services Real Estate Services Real Estate Services Real Estate Services  
Investment, Acquisition Date Nov. 16, 2021 Nov. 16, 2021          
Investment Owned, Balance, Shares | shares 15   15 15 15    
Investment Owned, Balance, Principal Amount   $ 15,000          
Investment Owned, at Cost $ 840,000 840,000          
Investment Owned, at Fair Value $ 31,000 $ 162,000          
Percent of net assets   0.10%       0.10%  
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.59% 10.40% 10.59% 10.59% 10.59% 10.40%  
Investment, Acquisition Date Sep. 11, 2024 Sep. 11, 2024          
Investment Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029  
Investment Owned, Balance, Principal Amount | £         £ 158    
Investment Owned, at Cost $ 206,000            
Investment Owned, at Fair Value $ 205,000 $ 2,000          
Investment, Interest Rate, Paid in Kind 0.25%   0.25% 0.25% 0.25%    
Investment, Interest Rate, Paid in Cash 10.34%   10.34% 10.34% 10.34%    
Fair Value As A Percentage of Member's Equity 0.60%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.59% 10.40% 10.59% 10.59% 10.59% 10.40%  
Investment, Acquisition Date Sep. 11, 2024 Sep. 11, 2024          
Investment Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029  
Investment Owned, Balance, Principal Amount   $ 513,000     £ 553    
Investment Owned, at Cost $ 721,000 665,000          
Investment Owned, at Fair Value $ 717,000 $ 643,000          
Investment, Interest Rate, Paid in Kind 0.25%   0.25% 0.25% 0.25%    
Investment, Interest Rate, Paid in Cash 10.34%   10.34% 10.34% 10.34%    
Fair Value As A Percentage of Member's Equity 2.20% 1.90%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.60% 10.25% 10.60% 10.60% 10.60% 10.25%  
Investment, Acquisition Date Sep. 11, 2024 Sep. 11, 2024          
Investment Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029  
Investment Owned, Balance, Principal Amount $ 134,000 $ 29,000          
Investment Owned, at Cost 133,000 29,000          
Investment Owned, at Fair Value $ 129,000 $ 30,000          
Investment, Interest Rate, Paid in Kind 0.25%   0.25% 0.25% 0.25%    
Investment, Interest Rate, Paid in Cash 10.35%   10.35% 10.35% 10.35%    
Fair Value As A Percentage of Member's Equity 0.40% 0.10%          
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.07% 9.14% 9.07% 9.07% 9.07% 9.14%  
Investment, Acquisition Date Sep. 11, 2024 Sep. 11, 2024          
Investment Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029  
Investment Owned, Balance, Principal Amount   $ 594,000   € 616      
Investment Owned, at Cost $ 676,000 649,000          
Investment Owned, at Fair Value $ 694,000 $ 611,000          
Investment, Interest Rate, Paid in Kind 0.25%   0.25% 0.25% 0.25%    
Investment, Interest Rate, Paid in Cash 8.82%   8.82% 8.82% 8.82%    
Fair Value As A Percentage of Member's Equity 2.10% 1.80%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.89% 10.34% 10.89% 10.89% 10.89% 10.34%  
Investment, Acquisition Date Sep. 11, 2024 Sep. 11, 2024          
Investment Maturity Date May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029 May 04, 2029  
Investment Owned, Balance, Principal Amount $ 3,508,000 $ 3,350,000          
Investment Owned, at Cost 3,485,000 3,319,000          
Investment Owned, at Fair Value $ 3,369,000 $ 3,344,000          
Investment, Interest Rate, Paid in Kind 0.25%   0.25% 0.25% 0.25%    
Investment, Interest Rate, Paid in Cash 10.64%   10.64% 10.64% 10.64%    
Fair Value As A Percentage of Member's Equity 10.20% 9.70%          
Investment, Identifier [Axis]: Chase Products Co. (f/k/a Starco) Second Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.17%   9.17% 9.17% 9.17%    
Investment, Acquisition Date Mar. 16, 2023 Mar. 16, 2023          
Investment Maturity Date Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028 Mar. 16, 2028  
Investment Owned, Balance, Principal Amount $ 3,404,000 $ 3,342,000          
Investment Owned, at Cost 3,404,000 3,342,000          
Investment Owned, at Fair Value $ 3,404,000 $ 3,342,000         2,793,000
Investment, Interest Rate, Paid in Kind 0.18% 12.00% 0.18% 0.18% 0.18% 12.00%  
Investment, Interest Rate, Paid in Cash 8.99%   8.99% 8.99% 8.99%    
Percent of net assets 1.30% 1.20% 1.30% 1.30% 1.30% 1.20%  
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member] Construction Materials [Member] Construction Materials [Member] Construction Materials [Member] Construction Materials [Member] Construction Materials [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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 13.54% 14.13% 13.54% 13.54% 13.54% 14.13%  
Investment, Acquisition Date Dec. 30, 2020 Dec. 30, 2020          
Investment Maturity Date Mar. 31, 2027 Dec. 30, 2025 Mar. 31, 2027 Mar. 31, 2027 Mar. 31, 2027 Dec. 30, 2025  
Investment Owned, Balance, Principal Amount $ 561,000 $ 632,000          
Investment Owned, at Cost 561,000 630,000          
Investment Owned, at Fair Value $ 498,000 $ 555,000          
Investment, Interest Rate, Paid in Kind 4.19% 2.25% 4.19% 4.19% 4.19% 2.25%  
Investment, Interest Rate, Paid in Cash 9.11% 11.88% 9.11% 9.11% 9.11% 11.88%  
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%  
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Construction Materials [Member] Construction Materials [Member] Construction Materials [Member] Construction Materials [Member] Construction Materials [Member]  
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  
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 8.75% 8.75% 8.75% 8.75% 8.75% 8.75%  
Investment Interest Rate 12.57% 13.21% 12.57% 12.57% 12.57% 13.21%  
Investment, Acquisition Date Dec. 30, 2020 Dec. 30, 2020          
Investment Maturity Date Mar. 31, 2027 Dec. 30, 2025 Mar. 31, 2027 Mar. 31, 2027 Mar. 31, 2027 Dec. 30, 2025  
Investment Owned, Balance, Principal Amount $ 5,124,000 $ 5,711,000          
Investment Owned, at Cost 5,123,000 5,690,000          
Investment Owned, at Fair Value $ 4,661,000 $ 5,085,000          
Investment, Interest Rate, Paid in Kind 4.38% 2.25% 4.38% 4.38% 4.38% 2.25%  
Investment, Interest Rate, Paid in Cash 8.19% 10.96% 8.19% 8.19% 8.19% 10.96%  
Percent of net assets 1.80% 1.80% 1.80% 1.80% 1.80% 1.80%  
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.11%       10.11%  
Investment, Acquisition Date   Jun. 14, 2024          
Investment Maturity Date   May 10, 2029       May 10, 2029  
Investment Owned, Balance, Principal Amount   $ 5,006,000          
Investment Owned, at Cost   4,919,000          
Investment Owned, at Fair Value   $ 4,993,000          
Fair Value As A Percentage of Member's Equity   14.40%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.47%   9.47% 9.47% 9.47%    
Investment, Acquisition Date Jun. 14, 2024            
Investment Maturity Date May 10, 2029   May 10, 2029 May 10, 2029 May 10, 2029    
Investment Owned, Balance, Principal Amount $ 4,956,000            
Investment Owned, at Cost 4,889,000            
Investment Owned, at Fair Value $ 4,928,000            
Fair Value As A Percentage of Member's Equity 15.00%            
Investment, Identifier [Axis]: CleanChoice Energy, Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]       Electric Utilities [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Spread Above Index   7.59%       7.59%  
Investment Interest Rate   12.39%       12.39%  
Investment, Acquisition Date   Oct. 12, 2021          
Investment Maturity Date   Oct. 12, 2026       Oct. 12, 2026  
Investment Owned, Balance, Principal Amount   $ 15,955,000          
Investment Owned, at Cost   15,802,000          
Investment Owned, at Fair Value   $ 16,032,000          
Percent of net assets   5.60%       5.60%  
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member]       Broadcasting [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Dec. 30, 2021          
Investment Maturity Date   Dec. 30, 2026       Dec. 30, 2026  
Investment Owned, at Fair Value   $ 1,000          
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]       Broadcasting [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Dec. 30, 2021          
Investment Maturity Date   Dec. 30, 2026       Dec. 30, 2026  
Investment Owned, Balance, Principal Amount   $ 7,879,000          
Investment Owned, at Cost   7,808,000          
Investment Owned, at Fair Value   $ 7,832,000          
Percent of net assets   2.70%       2.70%  
Investment, Identifier [Axis]: Colonnade Parent, Inc. (d/b/a Naviga Inc.) First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 1.00%   1.00% 1.00% 1.00%    
Investment Interest Rate 4.77%   4.77% 4.77% 4.77%    
Investment, Acquisition Date Jun. 14, 2019            
Investment Maturity Date Sep. 30, 2026   Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026    
Investment Owned, Balance, Principal Amount $ 301,000            
Investment Owned, at Cost 287,000            
Investment Owned, at Fair Value $ 158,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
Investment, Identifier [Axis]: Colonnade Parent, Inc. (d/b/a Naviga Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 1.00%   1.00% 1.00% 1.00%    
Investment Interest Rate 4.77%   4.77% 4.77% 4.77%    
Investment, Acquisition Date Jun. 14, 2019            
Investment Maturity Date Sep. 30, 2026   Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026    
Investment Owned, Balance, Principal Amount $ 3,667,000            
Investment Owned, at Cost 2,988,000            
Investment Owned, at Fair Value $ 1,925,000            
Percent of net assets 0.70%   0.70% 0.70% 0.70%    
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   10.48%       10.48%  
Investment, Acquisition Date   Nov. 09, 2020          
Investment Maturity Date   Dec. 07, 2026       Dec. 07, 2026  
Investment Owned, Balance, Principal Amount   $ 13,501,000          
Investment Owned, at Cost   13,445,000          
Investment Owned, at Fair Value   $ 13,437,000          
Fair Value As A Percentage of Member's Equity   38.80%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.82%   9.82% 9.82% 9.82%    
Investment, Acquisition Date Nov. 09, 2020            
Investment Maturity Date Dec. 07, 2026   Dec. 07, 2026 Dec. 07, 2026 Dec. 07, 2026    
Investment Owned, Balance, Principal Amount $ 13,358,000            
Investment Owned, at Cost 13,331,000            
Investment Owned, at Fair Value $ 13,314,000            
Fair Value As A Percentage of Member's Equity 40.50%            
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.50%       5.50%  
Investment Interest Rate   9.98%       9.98%  
Investment, Acquisition Date   Jul. 15, 2021          
Investment Maturity Date   Jun. 23, 2027       Jun. 23, 2027  
Investment Owned, Balance, Principal Amount   $ 8,342,000          
Investment Owned, at Cost   8,299,000          
Investment Owned, at Fair Value   $ 8,342,000          
Fair Value As A Percentage of Member's Equity   24.10%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Nov. 20, 2025            
Investment 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Nov. 20, 2025            
Investment 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Nov. 20, 2025            
Investment Maturity Date Nov. 14, 2031   Nov. 14, 2031 Nov. 14, 2031 Nov. 14, 2031    
Investment Owned, Balance, Principal Amount $ 5,543,000            
Investment Owned, at Cost 5,488,000            
Investment Owned, at Fair Value $ 5,488,000            
Fair Value As A Percentage of Member's Equity 16.70%            
Investment, Identifier [Axis]: Eddy Acquisitions, LLC (d/b/a EducationDynamics, LLC) Preferred Units              
Schedule of Investments [Line Items]              
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 [Member]       Education Services [Member]  
Investment, Acquisition Date   Sep. 15, 2021          
Investment Owned, Balance, Principal Amount   $ 167,000          
Investment Owned, at Cost   $ 167,000          
Investment, Identifier [Axis]: Eddy Acquisitions, LLC Preferred Units              
Schedule of Investments [Line Items]              
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 [Member]   Education Services [Member] Education Services [Member] Education Services [Member]    
Investment, Acquisition Date Sep. 15, 2021            
Investment Owned, Balance, Shares | shares 167   167 167 167    
Investment Owned, at Cost $ 167,000            
Investment, Identifier [Axis]: Education Dynamics, LLC Senior Preferred Units              
Schedule of Investments [Line Items]              
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 [Member] Education Services [Member] Education Services [Member] Education Services [Member] Education Services [Member] Education Services [Member]  
Investment, Acquisition Date Sep. 15, 2021 Sep. 15, 2021          
Investment Owned, Balance, Shares | shares 167   167 167 167    
Investment Owned, Balance, Principal Amount   $ 167,000          
Investment Owned, at Cost $ 167,000 167,000          
Investment Owned, at Fair Value   $ 100,000          
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member] Education Services [Member] Education Services [Member] Education Services [Member] Education Services [Member] Education Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration] Prime Rate [Member] whfcl:SecuredOvernightFinancingRateMember Prime Rate [Member] Prime Rate [Member] Prime Rate [Member] whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, 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%  
Investment Interest Rate 12.25% 10.96% 12.25% 12.25% 12.25% 10.96%  
Investment, Acquisition Date Sep. 15, 2021 Sep. 15, 2021          
Investment Maturity Date Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027  
Investment Owned, Balance, Principal Amount $ 360,000            
Investment Owned, at Cost 358,000            
Investment Owned, at Fair Value $ 320,000 $ (51,000)          
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Education Services [Member] Education Services [Member] Education Services [Member] Education Services [Member] Education Services [Member]  
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.32% 10.96% 10.32% 10.32% 10.32% 10.96%  
Investment, Acquisition Date Sep. 15, 2021 Sep. 15, 2021          
Investment Maturity Date Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027 Sep. 15, 2027  
Investment Owned, Balance, Principal Amount $ 12,592,000 $ 13,089,000          
Investment Owned, at Cost 12,532,000 12,989,000          
Investment Owned, at 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, Identifier [Axis]: Event Services America, Inc. (d/b/a Contemporary Services Corporation) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]       Security & Alarm Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.75%       6.75%  
Investment Interest Rate   11.11%       11.11%  
Investment, Acquisition Date   Jan. 31, 2024          
Investment Maturity Date   Jan. 31, 2029       Jan. 31, 2029  
Investment Owned, Balance, Principal Amount   $ 7,000,000          
Investment Owned, at Cost   6,857,000          
Investment Owned, at Fair Value   $ 7,070,000          
Percent of net assets   2.50%       2.50%  
Investment, Identifier [Axis]: FGI Acquisition Corp. First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.98%       10.98%  
Investment, Acquisition Date   Oct. 28, 2019          
Investment Maturity Date   Oct. 29, 2026       Oct. 29, 2026  
Investment Owned, Balance, Principal Amount   $ 16,026,000          
Investment Owned, at Cost   15,765,000          
Investment Owned, at Fair Value   $ 16,026,000          
Percent of net assets   5.60%       5.60%  
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.57% 10.40% 8.57% 8.57% 8.57% 10.40%  
Investment, Acquisition Date Dec. 12, 2024 Dec. 12, 2024          
Investment Maturity Date Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031  
Investment Owned, Balance, Principal Amount $ 667,000            
Investment Owned, at Cost 661,000            
Investment Owned, at Fair Value $ 663,000            
Fair Value As A Percentage of Member's Equity 2.00%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.57% 9.27% 8.57% 8.57% 8.57% 9.27%  
Investment, Acquisition Date Dec. 12, 2024 Dec. 12, 2024          
Investment Maturity Date Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031  
Investment Owned, Balance, Principal Amount $ 5,293,000 $ 5,333,000          
Investment Owned, at Cost 5,248,000 5,280,000          
Investment Owned, at Fair Value $ 5,262,000 $ 5,281,000          
Fair Value As A Percentage of Member's Equity 16.00% 15.30%          
Investment, Identifier [Axis]: Foodservices Brand Group, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.62%       12.62%  
Investment, Acquisition Date   Nov. 22, 2022          
Investment Maturity Date   Dec. 09, 2025       Dec. 09, 2025  
Investment Owned, Balance, Principal Amount   $ 357,000          
Investment Owned, at Cost   357,000          
Investment Owned, at Fair Value   $ 321,000          
Percent of net assets   0.10%       0.10%  
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.57% 11.23% 10.57% 10.57% 10.57% 11.23%  
Investment, Acquisition Date Mar. 11, 2022 Mar. 11, 2022          
Investment Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026  
Investment Owned, Balance, Principal Amount $ 2,993,000 $ 3,023,000          
Investment Owned, at Cost 2,981,000 3,000,000          
Investment Owned, at Fair Value $ 2,993,000 $ 3,023,000          
Fair Value As A Percentage of Member's Equity 9.10% 8.70%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.69% 11.23% 10.69% 10.69% 10.69% 11.23%  
Investment, Acquisition Date Feb. 18, 2022 Feb. 18, 2022          
Investment Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026  
Investment Owned, Balance, Principal Amount $ 619,000            
Investment Owned, at Cost 617,000            
Investment Owned, at Fair Value $ 619,000 $ 5,000          
Fair Value As A Percentage of Member's Equity 1.90%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.57% 11.23% 10.57% 10.57% 10.57% 11.23%  
Investment, Acquisition Date Feb. 18, 2022 Feb. 18, 2022          
Investment Maturity Date Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026 Dec. 15, 2026  
Investment Owned, Balance, Principal Amount $ 8,914,000 $ 9,007,000          
Investment Owned, at Cost 8,880,000 8,937,000          
Investment Owned, at Fair Value $ 8,914,000 $ 9,007,000          
Fair Value As A Percentage of Member's Equity 27.10% 26.10%          
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 7.00%   7.00% 7.00% 7.00%    
Investment Interest Rate 10.67%   10.67% 10.67% 10.67%    
Investment, Acquisition Date Jul. 31, 2025            
Investment Maturity Date Jul. 31, 2029   Jul. 31, 2029 Jul. 31, 2029 Jul. 31, 2029    
Investment Owned, Balance, Principal Amount $ 250,000            
Investment Owned, at Cost 248,000            
Investment Owned, at Fair Value $ 272,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 7.00%   7.00% 7.00% 7.00%    
Investment Interest Rate 10.67%   10.67% 10.67% 10.67%    
Investment, Acquisition Date Jul. 31, 2025            
Investment Maturity Date Jul. 31, 2029   Jul. 31, 2029 Jul. 31, 2029 Jul. 31, 2029    
Investment Owned, at Fair Value $ 8,000            
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 7.00%   7.00% 7.00% 7.00%    
Investment Interest Rate 10.67%   10.67% 10.67% 10.67%    
Investment, Acquisition Date Jul. 31, 2025            
Investment Maturity Date Jul. 31, 2029   Jul. 31, 2029 Jul. 31, 2029 Jul. 31, 2029    
Investment Owned, Balance, Principal Amount $ 4,364,000            
Investment Owned, at Cost 4,286,000            
Investment Owned, at Fair Value $ 4,343,000            
Percent of net assets 1.70%   1.70% 1.70% 1.70%    
Investment, Identifier [Axis]: Future Payment Technologies, LP First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 12.22% 12.90% 12.22% 12.22% 12.22% 12.90%  
Investment, Acquisition Date Dec. 23, 2016 Dec. 23, 2016          
Investment Maturity Date Dec. 07, 2026 Dec. 05, 2025 Dec. 07, 2026 Dec. 07, 2026 Dec. 07, 2026 Dec. 05, 2025  
Investment Owned, Balance, Principal Amount $ 19,175,000 $ 20,420,000          
Investment Owned, at Cost 19,160,000 20,382,000          
Investment Owned, at 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, 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.72%   8.72% 8.72% 8.72%    
Investment, Acquisition Date Mar. 05, 2025            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.72%   8.72% 8.72% 8.72%    
Investment, Acquisition Date Mar. 05, 2025            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.72%   8.72% 8.72% 8.72%    
Investment, Acquisition Date Mar. 05, 2025            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, Balance, Principal Amount $ 3,900,000            
Investment Owned, at Cost 3,850,000            
Investment Owned, at Fair Value $ 3,873,000            
Fair Value As A Percentage of Member's Equity 11.70%            
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 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.73%   9.73% 9.73% 9.73%    
Investment, Acquisition Date Apr. 15, 2025            
Investment Maturity Date Apr. 15, 2031   Apr. 15, 2031 Apr. 15, 2031 Apr. 15, 2031    
Investment Owned, Balance, Principal Amount $ 15,283,000            
Investment Owned, at Cost 15,014,000            
Investment Owned, at Fair Value $ 15,129,000            
Percent of net assets 5.80%   5.80% 5.80% 5.80%    
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   9.49%       9.49%  
Investment, Acquisition Date   Jan. 22, 2020          
Investment Maturity Date   Dec. 21, 2026       Dec. 21, 2026  
Investment Owned, at 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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   9.49%       9.49%  
Investment, Acquisition Date   Jan. 22, 2020          
Investment Maturity Date   Dec. 21, 2026       Dec. 21, 2026  
Investment Owned, Balance, Principal Amount   $ 18,415,000          
Investment Owned, at Cost   14,234,000          
Investment Owned, at Fair Value   $ 12,883,000          
Fair Value As A Percentage of Member's Equity   37.20%          
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.72% 11.95% 10.72% 10.72% 10.72% 11.95%  
Investment, Acquisition Date Dec. 16, 2022 Dec. 16, 2022          
Investment Maturity Date Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028  
Investment Owned, Balance, Principal Amount $ 605,000 $ 453,000          
Investment Owned, at Cost 596,000 444,000          
Investment Owned, at Fair Value $ 584,000 $ 447,000          
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%  
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.72% 11.96% 10.72% 10.72% 10.72% 11.96%  
Investment, Acquisition Date Dec. 16, 2022 Dec. 16, 2022          
Investment Maturity Date Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028 Dec. 18, 2028  
Investment Owned, Balance, Principal Amount $ 8,956,000 $ 8,994,000          
Investment Owned, at Cost 8,820,000 8,811,000          
Investment Owned, at Fair Value $ 8,697,000 $ 8,857,000          
Investment, Interest Rate, Paid in Kind 1.00%   1.00% 1.00% 1.00%    
Investment, Interest Rate, Paid in Cash 9.72%   9.72% 9.72% 9.72%    
Percent of net assets 3.30% 3.10% 3.30% 3.30% 3.30% 3.10%  
Investment, Identifier [Axis]: H I G Camarillo, LP, Limited Partners Interests              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]  
Investment, Acquisition Date Sep. 25, 2024 Sep. 25, 2024          
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 Real Estate Services Real Estate Services Real Estate Services Real Estate Services Real Estate Services  
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.55% 11.29% 10.55% 10.55% 10.55% 11.29%  
Investment, Acquisition Date Feb. 18, 2022 Feb. 18, 2022          
Investment Maturity Date Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026  
Investment Owned, Balance, Principal Amount $ 1,154,000 $ 1,395,000          
Investment Owned, at Cost 1,150,000 1,384,000          
Investment Owned, at Fair Value $ 1,154,000 $ 1,354,000          
Fair Value As A Percentage of Member's Equity 3.50% 3.90%          
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 Real Estate Services Real Estate Services Real Estate Services Real Estate Services Real Estate 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.27% 11.02% 10.27% 10.27% 10.27% 11.02%  
Investment, Acquisition Date Feb. 18, 2022 Feb. 18, 2022          
Investment Maturity Date Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026  
Investment Owned, Balance, Principal Amount $ 700,000 $ 483,000          
Investment Owned, at Cost 698,000 480,000          
Investment Owned, at Fair Value $ 701,000 $ 455,000          
Fair Value As A Percentage of Member's Equity 2.10% 1.30%          
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 Real Estate Services Real Estate Services Real Estate Services Real Estate Services Real Estate 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.27% 11.02% 10.27% 10.27% 10.27% 11.02%  
Investment, Acquisition Date Dec. 28, 2021 Dec. 28, 2021          
Investment Maturity Date Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026 Oct. 19, 2026  
Investment Owned, Balance, Principal Amount $ 4,602,000 $ 5,563,000          
Investment Owned, at Cost 4,588,000 5,523,000          
Investment Owned, at Fair Value $ 4,602,000 $ 5,395,000          
Fair Value As A Percentage of Member's Equity 14.00% 15.60%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.83% 10.35% 9.83% 9.83% 9.83% 10.35%  
Investment, Acquisition Date Feb. 17, 2022 Feb. 17, 2022          
Investment Maturity Date Jun. 14, 2027 Jun. 15, 2026 Jun. 14, 2027 Jun. 14, 2027 Jun. 14, 2027 Jun. 15, 2026  
Investment Owned, at 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.83% 10.35% 9.83% 9.83% 9.83% 10.35%  
Investment, Acquisition Date Feb. 17, 2022 Feb. 17, 2022          
Investment Maturity Date Jun. 14, 2027 Jun. 15, 2026 Jun. 14, 2027 Jun. 14, 2027 Jun. 14, 2027 Jun. 15, 2026  
Investment Owned, Balance, Principal Amount $ 3,271,000 $ 3,307,000          
Investment Owned, at Cost 3,262,000 3,286,000          
Investment Owned, at Fair Value $ 3,271,000 $ 3,307,000          
Fair Value As A Percentage of Member's Equity 10.00% 9.60%          
Investment, Identifier [Axis]: ImageOne Industries, LLC Common A Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Sep. 20, 2019 Sep. 20, 2019          
Investment Owned, Balance, Shares | shares 238   238 238 238    
Investment Owned, Balance, Principal Amount   $ 235,000          
Investment Owned, at Cost $ 13,000 10,000          
Investment Owned, at Fair Value   $ 12,000          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.50%   4.50% 4.50% 4.50%    
Investment Interest Rate 8.17%   8.17% 8.17% 8.17%    
Investment, Acquisition Date May 01, 2025            
Investment Maturity Date Mar. 21, 2031   Mar. 21, 2031 Mar. 21, 2031 Mar. 21, 2031    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.50%   4.50% 4.50% 4.50%    
Investment Interest Rate 8.17%   8.17% 8.17% 8.17%    
Investment, Acquisition Date May 01, 2025            
Investment Maturity Date Mar. 21, 2031   Mar. 21, 2031 Mar. 21, 2031 Mar. 21, 2031    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.50%   4.50% 4.50% 4.50%    
Investment Interest Rate 8.17%   8.17% 8.17% 8.17%    
Investment, Acquisition Date May 01, 2025            
Investment Maturity Date Mar. 21, 2031   Mar. 21, 2031 Mar. 21, 2031 Mar. 21, 2031    
Investment Owned, Balance, Principal Amount $ 4,169,000            
Investment Owned, at Cost 4,132,000            
Investment Owned, at Fair Value $ 4,169,000            
Fair Value As A Percentage of Member's Equity 12.70%            
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Revolving Loan              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.42%   9.42% 9.42% 9.42%    
Investment, Acquisition Date Feb. 19, 2025            
Investment Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030    
Investment Owned, at Fair Value $ 2,000            
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.42%   9.42% 9.42% 9.42%    
Investment, Acquisition Date Mar. 24, 2025            
Investment Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030    
Investment Owned, at Fair Value $ 1,000            
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.42%   9.42% 9.42% 9.42%    
Investment, Acquisition Date Feb. 19, 2025            
Investment Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030    
Investment Owned, Balance, Principal Amount $ 2,947,000            
Investment Owned, at Cost 2,899,000            
Investment Owned, at Fair Value $ 2,907,000            
Percent of net assets 1.10%   1.10% 1.10% 1.10%    
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.42%   9.42% 9.42% 9.42%    
Investment, Acquisition Date Mar. 24, 2025            
Investment Maturity Date Feb. 19, 2030   Feb. 19, 2030 Feb. 19, 2030 Feb. 19, 2030    
Investment Owned, Balance, Principal Amount $ 2,526,000            
Investment Owned, at Cost 2,484,000            
Investment Owned, at Fair Value $ 2,492,000            
Fair Value As A Percentage of Member's Equity 7.60%            
Investment, Identifier [Axis]: JVMC Holdings Corp First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 And Services [Member]       Interactive Media And Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.83%       10.83%  
Investment, Acquisition Date   Jan. 31, 2024          
Investment Maturity Date   Jan. 31, 2030       Jan. 31, 2030  
Investment Owned, Balance, Principal Amount   $ 14,087,000          
Investment Owned, at Cost   13,789,000          
Investment Owned, at Fair Value   $ 14,166,000          
Percent of net assets   5.00%       5.00%  
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.56%   9.56% 9.56% 9.56%    
Investment, Acquisition Date May 23, 2025            
Investment Maturity Date Dec. 29, 2027   Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027    
Investment Owned, Balance, Principal Amount $ 890,000            
Investment Owned, at Cost 884,000            
Investment Owned, at Fair Value $ 910,000            
Percent of net assets 0.40%   0.40% 0.40% 0.40%    
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.43% 10.85% 9.43% 9.43% 9.43% 10.85%  
Investment, Acquisition Date Mar. 01, 2022 Mar. 01, 2022          
Investment Maturity Date Dec. 29, 2027 Dec. 29, 2026 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2026  
Investment Owned, Balance, Principal Amount $ 2,319,000 $ 2,343,000          
Investment Owned, at Cost 2,309,000 2,326,000          
Investment Owned, at Fair Value $ 2,319,000 $ 2,343,000          
Fair Value As A Percentage of Member's Equity 7.10% 6.80%          
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.51%   9.51% 9.51% 9.51%    
Investment, Acquisition Date May 23, 2025            
Investment Maturity Date Dec. 29, 2027   Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027    
Investment Owned, Balance, Principal Amount $ 238,000            
Investment Owned, at Cost 235,000            
Investment Owned, at Fair Value $ 246,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.52% 10.82% 9.52% 9.52% 9.52% 10.82%  
Investment, Acquisition Date Mar. 01, 2022 Mar. 01, 2022          
Investment Maturity Date Dec. 29, 2027 Dec. 29, 2026 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2026  
Investment Owned, Balance, Principal Amount $ 310,000 $ 517,000          
Investment Owned, at Cost 309,000 513,000          
Investment Owned, at Fair Value $ 314,000 $ 522,000          
Fair Value As A Percentage of Member's Equity 1.00% 1.50%          
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.43%   9.43% 9.43% 9.43%    
Investment, Acquisition Date May 23, 2025            
Investment Maturity Date Dec. 29, 2027   Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027    
Investment Owned, Balance, Principal Amount $ 454,000            
Investment Owned, at Cost 449,000            
Investment Owned, at Fair Value $ 454,000            
Percent of net assets 0.20%   0.20% 0.20% 0.20%    
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.43% 10.84% 9.43% 9.43% 9.43% 10.84%  
Investment, Acquisition Date Mar. 01, 2022 Mar. 01, 2022          
Investment Maturity Date Dec. 29, 2027 Dec. 29, 2026 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2027 Dec. 29, 2026  
Investment Owned, Balance, Principal Amount $ 10,964,000 $ 11,078,000          
Investment Owned, at Cost 10,917,000 11,000,000          
Investment Owned, at Fair Value $ 10,964,000 $ 11,078,000          
Fair Value As A Percentage of Member's Equity 33.30% 32.00%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.38% 11.02% 10.38% 10.38% 10.38% 11.02%  
Investment, Acquisition Date Nov. 27, 2023 Nov. 27, 2023          
Investment Maturity Date Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028  
Investment Owned, at 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.38% 11.02% 10.38% 10.38% 10.38% 11.02%  
Investment, Acquisition Date Nov. 27, 2023 Nov. 27, 2023          
Investment Maturity Date Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028 Nov. 09, 2028  
Investment Owned, Balance, Principal Amount $ 6,290,000 $ 6,354,000          
Investment Owned, at Cost 6,218,000 6,256,000          
Investment Owned, at Fair Value $ 6,290,000 $ 6,323,000          
Fair Value As A Percentage of Member's Equity 19.10% 18.30%          
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.09%       10.09%  
Investment, Acquisition Date   Dec. 26, 2024          
Investment Maturity Date   Dec. 31, 2029       Dec. 31, 2029  
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.57% 10.09% 9.57% 9.57% 9.57% 10.09%  
Investment, Acquisition Date Dec. 26, 2024 Dec. 26, 2024          
Investment Maturity Date Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029 Dec. 31, 2029  
Investment Owned, Balance, Principal Amount $ 4,785,000 $ 3,611,000          
Investment Owned, at Cost 4,710,000 3,539,000          
Investment Owned, at 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, Identifier [Axis]: Keras Holdings, LLC Shares              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Dec. 31, 2020 Dec. 31, 2020          
Investment Owned, Balance, Shares | shares 496   496 496 496    
Investment Owned, Balance, Principal Amount   $ 496,000          
Investment Owned, at Cost $ 496,000 496,000          
Investment Owned, at Fair Value $ 446,000 $ 779,000          
Percent of net assets 0.20% 0.30% 0.20% 0.20% 0.20% 0.30%  
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.50%       8.50%  
Investment Interest Rate   12.99%       12.99%  
Investment, Acquisition Date   Jun. 22, 2021          
Investment Maturity Date   Feb. 24, 2026       Feb. 24, 2026  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.50%       8.50%  
Investment Interest Rate   12.99%       12.99%  
Investment, Acquisition Date   Jun. 22, 2021          
Investment Maturity Date   Feb. 24, 2026       Feb. 24, 2026  
Investment Owned, Balance, Principal Amount   $ 8,155,000          
Investment Owned, at Cost   8,114,000          
Investment Owned, at Fair Value   $ 8,155,000          
Fair Value As A Percentage of Member's Equity   23.70%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.25%   6.25% 6.25% 6.25%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Jun. 22, 2021            
Investment 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.25%   6.25% 6.25% 6.25%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Jun. 22, 2021            
Investment Maturity Date Feb. 24, 2026   Feb. 24, 2026 Feb. 24, 2026 Feb. 24, 2026    
Investment Owned, Balance, Principal Amount $ 7,900,000            
Investment Owned, at Cost 7,895,000            
Investment Owned, at Fair Value $ 7,900,000            
Fair Value As A Percentage of Member's Equity 24.00%            
Investment, Identifier [Axis]: LSCS Holdings, Inc. Second Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 And Services [Member]       Life Sciences Tools And Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   0.50%       0.50%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.47%       12.47%  
Investment, Acquisition Date   Nov. 23, 2021          
Investment Maturity Date   Dec. 16, 2029       Dec. 16, 2029  
Investment Owned, Balance, Principal Amount   $ 5,000,000          
Investment Owned, at Cost   4,953,000          
Investment Owned, at Fair Value   $ 5,000,000          
Percent of net assets   1.70%       1.70%  
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   7.25%       7.25%  
Investment Interest Rate   11.71%       11.71%  
Investment, Acquisition Date   Oct. 16, 2019          
Investment Maturity Date   Dec. 31, 2025       Dec. 31, 2025  
Investment Owned, Balance, Principal Amount   $ 5,020,000          
Investment Owned, at Cost   5,020,000          
Investment Owned, at Fair Value   $ 5,020,000          
Percent of net assets   1.80%       1.80%  
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   7.25%       7.25%  
Investment Interest Rate   11.71%       11.71%  
Investment, Acquisition Date   Sep. 17, 2024          
Investment Maturity Date   Dec. 31, 2025       Dec. 31, 2025  
Investment Owned, Balance, Principal Amount   $ 437,000          
Investment Owned, at Cost   437,000          
Investment Owned, at Fair Value   $ 437,000          
Percent of net assets   0.20%       0.20%  
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   7.25%       7.25%  
Investment Interest Rate   11.71%       11.71%  
Investment, Acquisition Date   Oct. 16, 2019          
Investment Maturity Date   Dec. 31, 2025       Dec. 31, 2025  
Investment Owned, Balance, Principal Amount   $ 5,383,000          
Investment Owned, at Cost   5,381,000          
Investment Owned, at Fair Value   $ 5,383,000          
Percent of net assets   1.90%       1.90%  
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.67% 11.98% 9.67% 9.67% 9.67% 11.98%  
Investment, Acquisition Date Dec. 27, 2022 Dec. 27, 2022          
Investment Maturity Date Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027  
Investment Owned, at Fair Value $ 4,000 $ 10,000          
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.67% 11.98% 9.67% 9.67% 9.67% 11.98%  
Investment, Acquisition Date Dec. 27, 2022 Dec. 27, 2022          
Investment Maturity Date Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027 Dec. 27, 2027  
Investment Owned, Balance, Principal Amount $ 13,645,000 $ 13,211,000          
Investment Owned, at Cost 13,486,000 12,981,000          
Investment Owned, at 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, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan A              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]  
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.32% 11.96% 11.32% 11.32% 11.32% 11.96%  
Investment, Acquisition Date Jun. 29, 2020 Jun. 29, 2020          
Investment Maturity Date Sep. 30, 2026 Jun. 29, 2025 Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026 Jun. 29, 2025  
Investment Owned, Balance, Principal Amount $ 5,120,000 $ 5,461,000          
Investment Owned, at Cost 5,119,000 5,453,000          
Investment Owned, at 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, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan B              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]  
Investment, Acquisition Date Jun. 29, 2020 Jun. 29, 2020          
Investment Maturity Date Sep. 30, 2026 Jun. 29, 2025 Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026 Jun. 29, 2025  
Investment Owned, Balance, Principal Amount $ 1,753,000 $ 1,594,000          
Investment Owned, at Cost 1,752,000 1,592,000          
Investment Owned, at Fair Value $ 1,753,000 $ 1,594,000          
Investment, Interest Rate, Paid in Kind 9.50% 9.50% 9.50% 9.50% 9.50% 9.50%  
Percent of net assets 0.70% 0.60% 0.70% 0.70% 0.70% 0.60%  
Investment, Identifier [Axis]: LogicMonitor, Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   0.75%       0.75%  
Spread Above Index   5.50%       5.50%  
Investment Interest Rate   9.99%       9.99%  
Investment, Acquisition Date   Nov. 19, 2024          
Investment Maturity Date   Nov. 19, 2031       Nov. 19, 2031  
Investment Owned, Balance, Principal Amount   $ 6,220,000          
Investment Owned, at Cost   6,144,000          
Investment Owned, at Fair Value   $ 6,144,000          
Percent of net assets   2.10%       2.10%  
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.34%   9.34% 9.34% 9.34%    
Investment, Acquisition Date Dec. 02, 2025            
Investment Maturity Date Nov. 19, 2031   Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031    
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.34% 9.99% 9.34% 9.34% 9.34% 9.99%  
Investment, Acquisition Date Nov. 19, 2024 Nov. 19, 2024          
Investment Maturity Date Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031  
Investment Owned, at Fair Value $ 5,000            
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.34%   9.34% 9.34% 9.34%    
Investment, Acquisition Date Nov. 19, 2024            
Investment Maturity Date Nov. 19, 2031   Nov. 19, 2031 Nov. 19, 2031 Nov. 19, 2031    
Investment Owned, Balance, Principal Amount $ 8,220,000            
Investment Owned, at Cost 8,130,000            
Investment Owned, at Fair Value $ 8,186,000            
Percent of net assets 3.20%   3.20% 3.20% 3.20%    
Investment, Identifier [Axis]: Luxury Brand Holdings, Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.11%       10.11%  
Investment, Acquisition Date   Dec. 04, 2020          
Investment Maturity Date   Jun. 04, 2026       Jun. 04, 2026  
Investment Owned, Balance, Principal Amount   $ 4,580,000          
Investment Owned, at Cost   4,556,000          
Investment Owned, at Fair Value   $ 4,580,000          
Percent of net assets   1.60%       1.60%  
Investment, Identifier [Axis]: M2S Group Intermediate Holdings, Inc. First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.59% 9.10% 8.59% 8.59% 8.59% 9.10%  
Investment, Acquisition Date Aug. 22, 2024 Aug. 22, 2024          
Investment Maturity Date Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031 Aug. 25, 2031  
Investment Owned, Balance, Principal Amount $ 9,368,000 $ 9,770,000          
Investment Owned, at Cost 8,838,000 9,119,000          
Investment Owned, at 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, Identifier [Axis]: MBS Highway, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 12.03% 13.20% 12.03% 12.03% 12.03% 13.20%  
Investment, Acquisition Date Oct. 13, 2022 Oct. 13, 2022          
Investment Maturity Date Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027 Oct. 13, 2027  
Investment Owned, Balance, Principal Amount $ 9,204,000 $ 9,286,000          
Investment Owned, at Cost 9,122,000 9,157,000          
Investment Owned, at Fair Value $ 9,184,000 $ 9,212,000          
Investment, Interest Rate, Paid in Kind   0.50%       0.50%  
Investment, Interest Rate, Paid in Cash   12.70%       12.70%  
Percent of net assets 3.50% 3.20% 3.50% 3.50% 3.50% 3.20%  
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 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.74%   8.74% 8.74% 8.74%    
Investment, Acquisition Date Apr. 08, 2025            
Investment Maturity Date Apr. 10, 2029   Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029    
Investment Owned, Balance, Principal Amount $ 283,000            
Investment Owned, at Cost 281,000            
Investment Owned, at Fair Value $ 300,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.72% 10.51% 8.72% 8.72% 8.72% 10.51%  
Investment, Acquisition Date May 10, 2023 May 10, 2023          
Investment Maturity Date Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029  
Investment Owned, Balance, Principal Amount $ 1,322,000 $ 821,000          
Investment Owned, at Cost 1,300,000 804,000          
Investment Owned, at Fair Value $ 1,322,000 $ 817,000          
Fair Value As A Percentage of Member's Equity 4.00% 2.40%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.50%       5.50%  
Investment Interest Rate   13.00%       13.00%  
Investment, Acquisition Date   May 10, 2023          
Investment Maturity Date   Apr. 10, 2028       Apr. 10, 2028  
Investment Owned, Balance, Principal Amount   $ 241,000          
Investment Owned, at Cost   236,000          
Investment Owned, at Fair Value   $ 249,000          
Fair Value As A Percentage of Member's Equity   0.70%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.39%       6.39%  
Investment Interest Rate   10.85%       10.85%  
Investment, Acquisition Date   May 10, 2023          
Investment Maturity Date   Apr. 10, 2029       Apr. 10, 2029  
Investment Owned, Balance, Principal Amount   $ 7,187,000          
Investment Owned, at Cost   7,040,000          
Investment Owned, at Fair Value   $ 7,176,000          
Fair Value As A Percentage of Member's Equity   20.70%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.00%   4.00% 4.00% 4.00%    
Investment Interest Rate 10.75%   10.75% 10.75% 10.75%    
Investment, Acquisition Date Apr. 07, 2025            
Investment Maturity Date Apr. 10, 2028   Apr. 10, 2028 Apr. 10, 2028 Apr. 10, 2028    
Investment Owned, Balance, Principal Amount $ 714,000            
Investment Owned, at Cost 705,000            
Investment Owned, at Fair Value $ 715,000            
Fair Value As A Percentage of Member's Equity 2.20%            
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.72%   8.72% 8.72% 8.72%    
Investment, Acquisition Date May 10, 2023            
Investment Maturity Date Apr. 10, 2029   Apr. 10, 2029 Apr. 10, 2029 Apr. 10, 2029    
Investment Owned, Balance, Principal Amount $ 8,555,000            
Investment Owned, at Cost 8,430,000            
Investment Owned, at Fair Value $ 8,567,000            
Fair Value As A Percentage of Member's Equity 26.10%            
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member]       Education Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   Base Rate [Member]       Base Rate [Member]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.82%       8.82%  
Investment, Acquisition Date   Apr. 25, 2022          
Investment Maturity Date   Apr. 24, 2026       Apr. 24, 2026  
Investment Owned, Balance, Principal Amount   $ 1,050,000          
Investment Owned, at Cost   1,043,000          
Investment Owned, at Fair Value   $ 945,000          
Investment, Interest Rate, Paid in Kind   16.11%       16.11%  
Percent of net assets   0.30%       0.30%  
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]       Education Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   9.75%       9.75%  
Investment, Acquisition Date   Apr. 25, 2022          
Investment Maturity Date   Apr. 24, 2026       Apr. 24, 2026  
Investment Owned, Balance, Principal Amount   $ 8,746,000          
Investment Owned, at Cost   8,552,000          
Investment Owned, at Fair Value   $ 7,871,000          
Investment, Interest Rate, Paid in Kind   14.23%       14.23%  
Percent of net assets   2.80%       2.80%  
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.00% 8.00% 6.00% 6.00% 6.00% 8.00%  
Investment Interest Rate 9.67% 12.43% 9.67% 9.67% 9.67% 12.43%  
Investment, Acquisition Date Apr. 07, 2023 Apr. 07, 2023          
Investment Maturity Date Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029  
Investment Owned, at Fair Value $ 4,000 $ 5,000          
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.67% 12.43% 9.67% 9.67% 9.67% 12.43%  
Investment, Acquisition Date Apr. 07, 2023 Apr. 07, 2023          
Investment Maturity Date Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029 Apr. 09, 2029  
Investment Owned, Balance, Principal Amount $ 4,827,000 $ 4,927,000          
Investment Owned, at Cost 4,748,000 4,823,000          
Investment Owned, at 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, 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.25%   4.25% 4.25% 4.25%    
Investment Interest Rate 8.12%   8.12% 8.12% 8.12%    
Investment, Acquisition Date Nov. 26, 2025            
Investment 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.25%   4.25% 4.25% 4.25%    
Investment Interest Rate 8.12%   8.12% 8.12% 8.12%    
Investment, Acquisition Date Nov. 26, 2025            
Investment 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.25%   4.25% 4.25% 4.25%    
Investment Interest Rate 8.12%   8.12% 8.12% 8.12%    
Investment, Acquisition Date Nov. 26, 2025            
Investment Maturity Date Nov. 21, 2031   Nov. 21, 2031 Nov. 21, 2031 Nov. 21, 2031    
Investment Owned, Balance, Principal Amount $ 6,045,000            
Investment Owned, at Cost 5,986,000            
Investment Owned, at Fair Value $ 5,985,000            
Fair Value As A Percentage of Member's Equity 18.20%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.32% 11.03% 10.32% 10.32% 10.32% 11.03%  
Investment, Acquisition Date Jul. 19, 2019 Jul. 19, 2019          
Investment Maturity Date Jul. 01, 2026 Jul. 01, 2025 Jul. 01, 2026 Jul. 01, 2026 Jul. 01, 2026 Jul. 01, 2025  
Investment Owned, at Fair Value $ (39,000) $ (38,000)          
Fair Value As A Percentage of Member's Equity (0.10%) (0.10%)          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.32% 11.03% 10.32% 10.32% 10.32% 11.03%  
Investment, Acquisition Date Jul. 19, 2019 Jul. 19, 2019          
Investment Maturity Date Jul. 01, 2026 Jul. 01, 2025 Jul. 01, 2026 Jul. 01, 2026 Jul. 01, 2026 Jul. 01, 2025  
Investment Owned, Balance, Principal Amount $ 18,019,000 $ 18,613,000          
Investment Owned, at Cost 18,019,000 18,577,000          
Investment Owned, at Fair Value $ 17,299,000 $ 17,865,000          
Fair Value As A Percentage of Member's Equity 52.60% 51.60%          
Investment, Identifier [Axis]: Max Solutions Inc. Common Stock              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Sep. 29, 2022 Sep. 29, 2022          
Investment Owned, Balance, Shares | shares 4   4 4 4    
Investment Owned, Balance, Principal Amount   $ 4,000          
Investment Owned, at Cost $ 400,000 $ 400,000          
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  
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.10%       8.10%  
Investment Interest Rate   12.56%       12.56%  
Investment, Acquisition Date   Oct. 07, 2022          
Investment Maturity Date   Sep. 29, 2028       Sep. 29, 2028  
Investment Owned, Balance, Principal Amount   $ 414,000          
Investment Owned, at Cost   411,000          
Investment Owned, at Fair Value   $ 402,000          
Fair Value As A Percentage of Member's Equity   1.20%          
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.10%       8.10%  
Investment Interest Rate   12.56%       12.56%  
Investment, Acquisition Date   Oct. 07, 2022          
Investment Maturity Date   Sep. 29, 2028       Sep. 29, 2028  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.11%       8.11%  
Investment Interest Rate   12.57%       12.57%  
Investment, Acquisition Date   Oct. 07, 2022          
Investment Maturity Date   Sep. 29, 2028       Sep. 29, 2028  
Investment Owned, Balance, Principal Amount   $ 6,521,000          
Investment Owned, at Cost   6,439,000          
Investment Owned, at Fair Value   $ 6,324,000          
Fair Value As A Percentage of Member's Equity   18.30%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.90%   6.90% 6.90% 6.90%    
Investment Interest Rate 10.89%   10.89% 10.89% 10.89%    
Investment, Acquisition Date Oct. 07, 2022            
Investment Maturity Date Sep. 29, 2028   Sep. 29, 2028 Sep. 29, 2028 Sep. 29, 2028    
Investment Owned, Balance, Principal Amount $ 410,000            
Investment Owned, at Cost 407,000            
Investment Owned, at Fair Value $ 408,000            
Fair Value As A Percentage of Member's Equity 1.20%            
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    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.90%   6.90% 6.90% 6.90%    
Investment Interest Rate 10.89%   10.89% 10.89% 10.89%    
Investment, Acquisition Date Oct. 07, 2022            
Investment Maturity Date Sep. 29, 2028   Sep. 29, 2028 Sep. 29, 2028 Sep. 29, 2028    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.91%   6.91% 6.91% 6.91%    
Investment Interest Rate 10.90%   10.90% 10.90% 10.90%    
Investment, Acquisition Date Oct. 07, 2022            
Investment Maturity Date Sep. 29, 2028   Sep. 29, 2028 Sep. 29, 2028 Sep. 29, 2028    
Investment Owned, Balance, Principal Amount $ 6,451,000            
Investment Owned, at Cost 6,392,000            
Investment Owned, at Fair Value $ 6,420,000            
Fair Value As A Percentage of Member's Equity 19.50%            
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 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.82%   9.82% 9.82% 9.82%    
Investment, Acquisition Date Dec. 27, 2024            
Investment Maturity Date Mar. 01, 2029   Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029    
Investment Owned, Balance, Principal Amount $ 938,000            
Investment Owned, at Cost 930,000            
Investment Owned, at Fair Value $ 942,000            
Percent of net assets 0.40%   0.40% 0.40% 0.40%    
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   10.46%       10.46%  
Investment, Acquisition Date   Dec. 27, 2024          
Investment Maturity Date   Mar. 01, 2029       Mar. 01, 2029  
Investment Owned, Balance, Principal Amount   $ 947,000          
Investment Owned, at Cost   938,000          
Investment Owned, at Fair Value   $ 938,000          
Percent of net assets   0.30%       0.30%  
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.82%   9.82% 9.82% 9.82%    
Investment, Acquisition Date Apr. 11, 2023            
Investment Maturity Date Mar. 01, 2029   Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029    
Investment Owned, at 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.82% 10.46% 9.82% 9.82% 9.82% 10.46%  
Investment, Acquisition Date Apr. 11, 2023 Apr. 11, 2023          
Investment Maturity Date Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029 Mar. 01, 2029  
Investment Owned, Balance, Principal Amount $ 4,951,000 $ 5,002,000          
Investment Owned, at Cost 4,872,000 4,898,000          
Investment Owned, at Fair Value $ 4,974,000 $ 4,986,000          
Fair Value As A Percentage of Member's Equity 15.10% 14.40%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   10.46%       10.46%  
Investment, Acquisition Date   Apr. 11, 2023          
Investment Maturity Date   Mar. 01, 2029       Mar. 01, 2029  
Investment Owned, at 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 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 [Member]   Education Services [Member] Education Services [Member] Education Services [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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.54%   9.54% 9.54% 9.54%    
Investment, Acquisition Date Sep. 01, 2025            
Investment Maturity Date Aug. 30, 2030   Aug. 30, 2030 Aug. 30, 2030 Aug. 30, 2030    
Investment Owned, at Fair Value $ 17,000            
Investment, Interest Rate, Paid in Kind 4.77%   4.77% 4.77% 4.77%    
Investment, Interest Rate, Paid in Cash 4.77%   4.77% 4.77% 4.77%    
Investment, Identifier [Axis]: Media Source, LLC (d/b/a Media Source Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]   Education Services [Member] Education Services [Member] Education Services [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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.54%   9.54% 9.54% 9.54%    
Investment, Acquisition Date Sep. 01, 2025            
Investment Maturity Date Aug. 30, 2030   Aug. 30, 2030 Aug. 30, 2030 Aug. 30, 2030    
Investment Owned, Balance, Principal Amount $ 4,242,000            
Investment Owned, at Cost 4,242,000            
Investment Owned, at Fair Value $ 4,242,000            
Investment, Interest Rate, Paid in Kind 4.77%   4.77% 4.77% 4.77%    
Investment, Interest Rate, Paid in Cash 4.77%   4.77% 4.77% 4.77%    
Percent of net assets 1.60%   1.60% 1.60% 1.60%    
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]  
Investment, Interest Rate, Floor   1.25%       1.25%  
Spread Above Index   6.25%       6.25%  
Investment Interest Rate   10.68%       10.68%  
Investment, Acquisition Date   Jul. 27, 2023          
Investment Maturity Date   Jul. 11, 2029       Jul. 11, 2029  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.25%       1.25%  
Spread Above Index   6.25%       6.25%  
Investment Interest Rate   10.68%       10.68%  
Investment, Acquisition Date   Jul. 27, 2023          
Investment Maturity Date   Jul. 11, 2029       Jul. 11, 2029  
Investment Owned, Balance, Principal Amount   $ 2,633,000          
Investment Owned, at Cost   2,584,000          
Investment Owned, at Fair Value   $ 2,660,000          
Fair Value As A Percentage of Member's Equity   7.70%          
Investment, Identifier [Axis]: Merriman Holdings LP (d/b/a Escalent, Inc.) Class A Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Apr. 07, 2023 Apr. 07, 2023          
Investment Owned, Balance, Shares | shares 327   327 327 327    
Investment Owned, Balance, Principal Amount   $ 327,000          
Investment Owned, at Cost $ 333,000 333          
Investment Owned, at Fair Value $ 312,000 $ 368,000          
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10% 0.10%  
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.94% 10.51% 8.94% 8.94% 8.94% 10.51%  
Investment, Acquisition Date Dec. 22, 2025 Dec. 16, 2021          
Investment Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031 Nov. 01, 2027  
Investment Owned, Balance, Principal Amount   $ 874,000          
Investment Owned, at Cost   865,000          
Investment Owned, at Fair Value   $ 874,000          
Fair Value As A Percentage of Member's Equity   2.50%          
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.94% 10.44% 8.94% 8.94% 8.94% 10.44%  
Investment, Acquisition Date Dec. 22, 2025 Dec. 16, 2021          
Investment Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031 Nov. 01, 2027  
Investment Owned, Balance, Principal Amount   $ 1,156,000          
Investment Owned, at Cost   1,145,000          
Investment Owned, at Fair Value   $ 1,160,000          
Fair Value As A Percentage of Member's Equity   3.40%          
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan One              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 7.29% 8.85% 7.29% 7.29% 7.29% 8.85%  
Investment, Acquisition Date Dec. 22, 2025 Dec. 16, 2021          
Investment Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031 Nov. 01, 2027  
Investment Owned, Balance, Principal Amount $ 4,621,000 $ 12,039,000          
Investment Owned, at Cost 5,378,000 13,449,000          
Investment Owned, at Fair Value $ 5,374,000 $ 12,465,000          
Fair Value As A Percentage of Member's Equity   36.00%          
Percent of net assets 2.10%   2.10% 2.10% 2.10%    
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan Two              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.94% 10.48% 8.94% 8.94% 8.94% 10.48%  
Investment, Acquisition Date Dec. 22, 2025 Dec. 16, 2021          
Investment Maturity Date Dec. 22, 2031 Nov. 01, 2027 Dec. 22, 2031 Dec. 22, 2031 Dec. 22, 2031 Nov. 01, 2027  
Investment Owned, Balance, Principal Amount $ 6,720,000 $ 962,000          
Investment Owned, at Cost 6,653,000 952,000          
Investment Owned, at Fair Value $ 6,653,000 $ 962,000          
Fair Value As A Percentage of Member's Equity   2.80%          
Percent of net assets 2.60%   2.60% 2.60% 2.60%    
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.32% 11.71% 11.32% 11.32% 11.32% 11.71%  
Investment, Acquisition Date Dec. 22, 2023 Dec. 22, 2023          
Investment Maturity Date Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028  
Investment Owned, Balance, Principal Amount $ 639,000 $ 645,000          
Investment Owned, at Cost 629,000 632,000          
Investment Owned, at Fair Value $ 639,000 $ 642,000          
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%  
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 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.32% 12.39% 11.32% 11.32% 11.32% 12.39%  
Investment, Acquisition Date Dec. 22, 2023 Dec. 22, 2023          
Investment Maturity Date Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028  
Investment Owned, Balance, Principal Amount $ 572,000 $ 326,000          
Investment Owned, at Cost 563,000 319,000          
Investment Owned, at Fair Value $ 572,000 $ 328,000          
Percent of net assets 0.20% 0.10% 0.20% 0.20% 0.20% 0.10%  
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.32% 11.71% 11.32% 11.32% 11.32% 11.71%  
Investment, Acquisition Date Dec. 22, 2023 Dec. 22, 2023          
Investment Maturity Date Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028 Dec. 22, 2028  
Investment Owned, Balance, Principal Amount $ 9,188,000 $ 9,443,000          
Investment Owned, at Cost 9,051,000 9,255,000          
Investment Owned, at 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, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 Real Estate Services Real Estate Services Real Estate Services Real Estate Services Real Estate 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.97% 11.16% 10.97% 10.97% 10.97% 11.16%  
Investment, Acquisition Date Jan. 10, 2024 Jan. 10, 2024          
Investment Maturity Date Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029  
Investment Owned, Balance, Principal Amount $ 1,579,000 $ 1,596,000          
Investment Owned, at Cost 1,562,000 1,572,000          
Investment Owned, at 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, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 Real Estate Services Real Estate Services Real Estate Services Real Estate Services Real Estate 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.92% 11.08% 10.92% 10.92% 10.92% 11.08%  
Investment, Acquisition Date Jan. 10, 2024 Jan. 10, 2024          
Investment Maturity Date Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029 Jan. 10, 2029  
Investment Owned, Balance, Principal Amount $ 9,212,000 $ 9,306,000          
Investment Owned, at Cost 9,073,000 9,119,000          
Investment Owned, at 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, Identifier [Axis]: Motivational CIV, LLC Class B Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Jul. 12, 2021 Jul. 12, 2021          
Investment Owned, Balance, Shares | shares 1,250   1,250 1,250 1,250    
Investment Owned, Balance, Principal Amount   $ 1,250,000          
Investment Owned, at Cost $ 1,250,000 $ 1,250,000          
Investment Owned, at Fair Value $ 774,000            
Percent of net assets 0.30%   0.30% 0.30% 0.30%    
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.48% 13.00% 10.48% 10.48% 10.48% 13.00%  
Investment, Acquisition Date Jul. 12, 2021 Jul. 12, 2021          
Investment Maturity Date Jul. 12, 2028 Jul. 12, 2026 Jul. 12, 2028 Jul. 12, 2028 Jul. 12, 2028 Jul. 12, 2026  
Investment Owned, Balance, Principal Amount $ 630,000 $ 1,182,000          
Investment Owned, at Cost 626,000 1,175,000          
Investment Owned, at Fair Value $ 637,000 $ 1,061,000          
Investment, Interest Rate, Paid in Kind   2.00%       2.00%  
Investment, Interest Rate, Paid in Cash   11.00%       11.00%  
Percent of net assets 0.20% 0.40% 0.20% 0.20% 0.20% 0.40%  
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.37% 12.96% 10.37% 10.37% 10.37% 12.96%  
Investment, Acquisition Date Jul. 12, 2021 Jul. 12, 2021          
Investment Maturity Date Jul. 12, 2028 Jul. 12, 2026 Jul. 12, 2028 Jul. 12, 2028 Jul. 12, 2028 Jul. 12, 2026  
Investment Owned, Balance, Principal Amount $ 13,175,000 $ 10,510,000          
Investment Owned, at Cost 13,104,000 10,449,000          
Investment Owned, at Fair Value $ 13,135,000 $ 9,438,000          
Investment, Interest Rate, Paid in Kind   7.48%       7.48%  
Investment, Interest Rate, Paid in Cash   5.48%       5.48%  
Percent of net assets 5.00% 3.20% 5.00% 5.00% 5.00% 3.20%  
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.67%   8.67% 8.67% 8.67%    
Investment, Acquisition Date Aug. 12, 2025            
Investment Maturity Date Jun. 30, 2031   Jun. 30, 2031 Jun. 30, 2031 Jun. 30, 2031    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.67%   8.67% 8.67% 8.67%    
Investment, Acquisition Date Aug. 12, 2025            
Investment Maturity Date Jun. 30, 2031   Jun. 30, 2031 Jun. 30, 2031 Jun. 30, 2031    
Investment Owned, Balance, Principal Amount $ 10,388,000            
Investment Owned, at Cost 10,293,000            
Investment Owned, at Fair Value $ 10,378,000            
Fair Value As A Percentage of Member's Equity 31.60%            
Investment, Identifier [Axis]: NNA Services, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.57% 11.73% 10.57% 10.57% 10.57% 11.73%  
Investment, Acquisition Date Aug. 27, 2021 Aug. 27, 2021          
Investment Maturity Date Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026 Aug. 27, 2026  
Investment Owned, Balance, Principal Amount $ 8,073,000 $ 9,125,000          
Investment Owned, at Cost 8,060,000 9,087,000          
Investment Owned, at 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, 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       Real Estate 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Mar. 01, 2022          
Investment Maturity Date   Jan. 21, 2027       Jan. 21, 2027  
Investment Owned, Balance, Principal Amount   $ 725,000          
Investment Owned, at Cost   719,000          
Investment Owned, at Fair Value   $ 660,000          
Fair Value As A Percentage of Member's Equity   1.90%          
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       Real Estate 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Mar. 01, 2022          
Investment Maturity Date   Jan. 21, 2027       Jan. 21, 2027  
Investment Owned, Balance, Principal Amount   $ 6,502,000          
Investment Owned, at Cost   6,448,000          
Investment Owned, at Fair Value   $ 5,918,000          
Fair Value As A Percentage of Member's Equity   17.10%          
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   Real Estate Services Real Estate Services Real Estate 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Mar. 01, 2022            
Investment Maturity Date Jan. 21, 2027   Jan. 21, 2027 Jan. 21, 2027 Jan. 21, 2027    
Investment Owned, Balance, Principal Amount $ 725,000            
Investment Owned, at Cost 722,000            
Investment Owned, at Fair Value $ 660,000            
Fair Value As A Percentage of Member's Equity 2.00%            
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   Real Estate Services Real Estate Services Real Estate 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Mar. 01, 2022            
Investment Maturity Date Jan. 21, 2027   Jan. 21, 2027 Jan. 21, 2027 Jan. 21, 2027    
Investment Owned, Balance, Principal Amount $ 5,517,000            
Investment Owned, at Cost 5,493,000            
Investment Owned, at Fair Value $ 5,022,000            
Fair Value As A Percentage of Member's Equity 15.30%            
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.84%       6.84%  
Investment Interest Rate   12.78%       12.78%  
Investment, Acquisition Date   Jun. 14, 2019          
Investment Maturity Date   Jun. 28, 2024       Jun. 28, 2024  
Investment Owned, Balance, Principal Amount   $ 301,000          
Investment Owned, at Cost   301,000          
Investment Owned, at Fair Value   $ 169,000          
Percent of net assets   0.10%       0.10%  
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   7.00%       7.00%  
Investment Interest Rate   12.40%       12.40%  
Investment, Acquisition Date   Jun. 14, 2019          
Investment Maturity Date   Jun. 28, 2024       Jun. 28, 2024  
Investment Owned, Balance, Principal Amount   $ 3,140,000          
Investment Owned, at Cost   3,140,000          
Investment Owned, at Fair Value   $ 1,763,000          
Percent of net assets   0.60%       0.60%  
Investment, Identifier [Axis]: New American Crafts Holdings, LLC Class A Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date   Mar. 16, 2023          
Investment Owned, Balance, Shares | shares   1       1  
Investment, Identifier [Axis]: Oil amp; Gas Storage amp; Transportation First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 and Gas Storage and Transportation [Member]   Oil and Gas Storage and Transportation [Member] Oil and Gas Storage and Transportation [Member] Oil and Gas Storage and Transportation [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]    
Investment, Interest Rate, Floor 0.50%   0.50% 0.50% 0.50%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.64%   9.64% 9.64% 9.64%    
Investment, Acquisition Date Jul. 16, 2025            
Investment Maturity Date Jul. 16, 2032   Jul. 16, 2032 Jul. 16, 2032 Jul. 16, 2032    
Investment Owned, Balance, Principal Amount $ 10,472,000            
Investment Owned, at Cost 10,077,000            
Investment Owned, at Fair Value $ 10,158,000            
Percent of net assets 3.90%   3.90% 3.90% 3.90%    
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.48% 10.15% 9.48% 9.48% 9.48% 10.15%  
Investment, Acquisition Date May 14, 2024 Jun. 14, 2024          
Investment Maturity Date May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029  
Investment Owned, Balance, Principal Amount   $ 30,000          
Investment Owned, at Cost   30,000          
Investment Owned, at Fair Value $ 6,000 $ 36,000          
Fair Value As A Percentage of Member's Equity   0.10%          
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan One              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.48% 10.15% 9.48% 9.48% 9.48% 10.15%  
Investment, Acquisition Date Jun. 14, 2024 May 14, 2024          
Investment Maturity Date May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029  
Investment Owned, Balance, Principal Amount   $ 27,000          
Investment Owned, at Cost   27,000          
Investment Owned, at Fair Value $ 6,000 $ 33,000          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.13%       10.13%  
Investment, Acquisition Date   Jun. 14, 2024          
Investment Maturity Date   May 14, 2029       May 14, 2029  
Investment Owned, Balance, Principal Amount   $ 4,520,000          
Investment Owned, at Cost   4,441,000          
Investment Owned, at Fair Value   $ 4,505,000          
Fair Value As A Percentage of Member's Equity   13.00%          
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan One              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.48% 10.13% 9.48% 9.48% 9.48% 10.13%  
Investment, Acquisition Date Jun. 14, 2024 May 14, 2024          
Investment Maturity Date May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029 May 14, 2029  
Investment Owned, Balance, Principal Amount $ 4,475,000 $ 4,068,000          
Investment Owned, at Cost 4,414,000 3,997,000          
Investment Owned, at Fair Value $ 4,475,000 $ 4,054,000          
Fair Value As A Percentage of Member's Equity 13.50%            
Percent of net assets   1.40%       1.40%  
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan, One 05/14/29              
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] 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.48%   9.48% 9.48% 9.48%    
Investment, Acquisition Date May 14, 2024            
Investment Maturity Date May 14, 2029   May 14, 2029 May 14, 2029 May 14, 2029    
Investment Owned, Balance, Principal Amount $ 4,027,000            
Investment Owned, at Cost 3,973,000            
Investment Owned, at Fair Value $ 4,027,000            
Percent of net assets 1.60%   1.60% 1.60% 1.60%    
Investment, Identifier [Axis]: PFB Holdco, Inc Class A Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date   Dec. 17, 2021          
Investment Owned, Balance, Shares | shares   1       1  
Investment Owned, at Cost   $ 24,000          
Investment, Identifier [Axis]: PFB Holding Company, LLC Class A Units              
Schedule of Investments [Line Items]              
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    
Investment, Acquisition Date Dec. 17, 2021            
Investment Owned, Balance, Shares | shares 1   1 1 1    
Investment Owned, at Cost $ 24,000            
Investment, Identifier [Axis]: PGI Parent LLC (d/b/a Prime Electric, Inc.) First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.67%   8.67% 8.67% 8.67%    
Investment, Acquisition Date Dec. 31, 2025            
Investment Maturity Date Dec. 31, 2031   Dec. 31, 2031 Dec. 31, 2031 Dec. 31, 2031    
Investment, Identifier [Axis]: PGI Parent LLC (d/b/a Prime Electric, Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.67%   8.67% 8.67% 8.67%    
Investment, Acquisition Date Dec. 31, 2025            
Investment Maturity Date Dec. 31, 2031   Dec. 31, 2031 Dec. 31, 2031 Dec. 31, 2031    
Investment Owned, Balance, Principal Amount $ 5,077,000            
Investment Owned, at Cost 5,026,000            
Investment Owned, at Fair Value $ 5,026,000            
Percent of net assets 1.90%   1.90% 1.90% 1.90%    
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   3.00%       3.00%  
Spread Above Index   9.00%       9.00%  
Investment Interest Rate   13.34%       13.34%  
Investment, Acquisition Date   Jan. 29, 2024          
Investment Maturity Date   Jan. 29, 2029       Jan. 29, 2029  
Investment Owned, Balance, Principal Amount   $ 889,000          
Investment Owned, at Cost   867,000          
Investment Owned, at Fair Value   $ 916,000          
Investment, Interest Rate, Paid in Kind   1.00%       1.00%  
Investment, Interest Rate, Paid in Cash   12.34%       12.34%  
Percent of net assets   0.30%       0.30%  
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, Floor   3.00%       3.00%  
Spread Above Index   9.00%       9.00%  
Investment Interest Rate   13.36%       13.36%  
Investment, Acquisition Date   Jan. 29, 2024          
Investment Maturity Date   Jan. 29, 2029       Jan. 29, 2029  
Investment Owned, Balance, Principal Amount   $ 7,950,000          
Investment Owned, at Cost   7,757,000          
Investment Owned, at Fair Value   $ 8,188,000          
Investment, Interest Rate, Paid in Kind   1.00%       1.00%  
Investment, Interest Rate, Paid in Cash   12.36%       12.36%  
Percent of net assets   3.00%       3.00%  
Investment, Identifier [Axis]: Patagonia Holdco LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.62% 10.27% 9.62% 9.62% 9.62% 10.27%  
Investment, Acquisition Date Aug. 05, 2022 Aug. 05, 2022          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, Balance, Principal Amount $ 14,150,000 $ 14,296,000          
Investment Owned, at Cost 12,839,000 12,602,000          
Investment Owned, at 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, 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.75%       6.75%  
Investment Interest Rate   11.23%       11.23%  
Investment, Acquisition Date   Mar. 17, 2023          
Investment Maturity Date   Feb. 07, 2028       Feb. 07, 2028  
Investment Owned, Balance, Principal Amount   $ 569,000          
Investment Owned, at Cost   558,000          
Investment Owned, at Fair Value   $ 569,000          
Fair Value As A Percentage of Member's Equity   1.70%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.75%       6.75%  
Investment Interest Rate   11.23%       11.23%  
Investment, Acquisition Date   Mar. 17, 2023          
Investment Maturity Date   Feb. 07, 2028       Feb. 07, 2028  
Investment Owned, Balance, Principal Amount   $ 338,000          
Investment Owned, at Cost   331,000          
Investment Owned, at Fair Value   $ 341,000          
Fair Value As A Percentage of Member's Equity   1.00%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.75%       6.75%  
Investment Interest Rate   11.23%       11.23%  
Investment, Acquisition Date   Mar. 17, 2023          
Investment Maturity Date   Feb. 07, 2028       Feb. 07, 2028  
Investment Owned, Balance, Principal Amount   $ 5,117,000          
Investment Owned, at Cost   5,015,000          
Investment Owned, at Fair Value   $ 5,111,000          
Fair Value As A Percentage of Member's Equity   14.80%          
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.20% 9.95% 8.20% 8.20% 8.20% 9.95%  
Investment, Acquisition Date Oct. 31, 2023 Oct. 31, 2023          
Investment Maturity Date Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028  
Investment Owned, at 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.20% 9.95% 8.20% 8.20% 8.20% 9.95%  
Investment, Acquisition Date Oct. 31, 2023 Oct. 31, 2023          
Investment Maturity Date Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028 Oct. 26, 2028  
Investment Owned, Balance, Principal Amount $ 12,389,000 $ 7,425,000          
Investment Owned, at Cost 12,284,000 7,298,000          
Investment Owned, at Fair Value $ 12,332,000 $ 7,425,000          
Fair Value As A Percentage of Member's Equity 37.50% 21.50%          
Investment, Identifier [Axis]: Playmonster Group Equity, Inc Common Stock              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Jan. 24, 2022 Jan. 24, 2022          
Investment Owned, Balance, Shares | shares 72   72 72 72    
Investment Owned, Balance, Principal Amount   $ 72,000          
Investment Owned, at Cost $ 460,000 $ 460,000          
Investment, Identifier [Axis]: Playmonster Group Equity, Inc. Preferred Stock              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Jan. 24, 2022 Jan. 24, 2022          
Investment Owned, Balance, Shares | shares 36   36 36 36    
Investment Owned, Balance, Principal Amount   $ 36,000          
Investment Owned, at Cost $ 3,600,000 $ 3,600,000          
Investment, Identifier [Axis]: Playmonster Group LLC, First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment, Acquisition Date Jun. 07, 2021 Jun. 07, 2021          
Investment Maturity Date Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026  
Investment Owned, Balance, Principal Amount $ 5,595,000 $ 4,890,000          
Investment Owned, at Cost 3,661,000 3,661,000          
Investment Owned, at Fair Value $ 1,729,000 $ 1,635,000         1,363,000
Investment, Interest Rate, Paid in Kind 12.99% 13.74% 12.99% 12.99% 12.99% 13.74%  
Percent of net assets 0.70% 0.60% 0.70% 0.70% 0.70% 0.60%  
Investment, Identifier [Axis]: Playmonster Group LLC, Priority First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment, Acquisition Date Dec. 09, 2022 Dec. 09, 2022          
Investment Maturity Date Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026 Jun. 08, 2026  
Investment Owned, Balance, Principal Amount $ 1,442,000 $ 1,289,000          
Investment Owned, at Cost 1,438,000 1,275,000          
Investment Owned, at Fair Value $ 1,355,000 $ 1,172,000         1,015,000
Investment, Interest Rate, Paid in Kind 10.74% 11.41% 10.74% 10.74% 10.74% 11.41%  
Percent of net assets 0.50% 0.40% 0.50% 0.50% 0.50% 0.40%  
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 [Member]       Heavy Electrical Equipment [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.75%       6.75%  
Investment Interest Rate   11.23%       11.23%  
Investment, Acquisition Date   Jul. 11, 2022          
Investment Maturity Date   Jun. 25, 2026       Jun. 25, 2026  
Investment Owned, Balance, Principal Amount   $ 1,340,000          
Investment Owned, at Cost   1,329,000          
Investment Owned, at Fair Value   $ 1,354,000          
Percent of net assets   0.50%       0.50%  
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]       Heavy Electrical Equipment [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.75%       6.75%  
Investment Interest Rate   11.23%       11.23%  
Investment, Acquisition Date   Jun. 25, 2021          
Investment Maturity Date   Jun. 25, 2026       Jun. 25, 2026  
Investment Owned, Balance, Principal Amount   $ 8,697,000          
Investment Owned, at Cost   8,642,000          
Investment Owned, at Fair Value   $ 8,784,000          
Percent of net assets   3.10%       3.10%  
Investment, Identifier [Axis]: Pressurized Holdings, LLC Common Units              
Schedule of Investments [Line Items]              
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 [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member]  
Investment, Acquisition Date Mar. 16, 2023 Mar. 16, 2023          
Investment, Identifier [Axis]: Pressurized Holdings, LLC Preferred Units              
Schedule of Investments [Line Items]              
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 [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member] Diversified Chemicals [Member]  
Investment, Acquisition Date Mar. 16, 2023 Mar. 16, 2023          
Investment Owned, at Cost $ 4,537,000 $ 4,537,000          
Investment Owned, at 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, 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 & Equipment whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember Electrical Components & Equipment  
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.96% 9.81% 8.96% 8.96% 8.96% 9.81%  
Investment, Acquisition Date Dec. 03, 2024 Dec. 03, 2024          
Investment Maturity Date Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030  
Investment Owned, at 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 & Equipment whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember whfcl:ElectronicEquipmentAndInstrumentsMember Electrical Components & Equipment  
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.96% 9.81% 8.96% 8.96% 8.96% 9.81%  
Investment, Acquisition Date Dec. 03, 2024 Dec. 03, 2024          
Investment Maturity Date Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030 Nov. 04, 2030  
Investment Owned, Balance, Principal Amount $ 3,353,000 $ 3,531,000          
Investment Owned, at Cost 3,312,000 3,479,000          
Investment Owned, at Fair Value $ 3,343,000 $ 3,479,000          
Fair Value As A Percentage of Member's Equity 10.20% 10.10%          
Investment, Identifier [Axis]: Quest Events, LLC Common Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Dec. 28, 2018 Dec. 28, 2018          
Investment Owned, Balance, Shares | shares 385   385 385 385    
Investment Owned, Balance, Principal Amount   $ 333,000          
Investment Owned, at Cost $ 385,000 376,000          
Investment Owned, at Fair Value   $ 149,000          
Percent of net assets   0.10%       0.10%  
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 7.50%   7.50% 7.50% 7.50%    
Investment Interest Rate 11.48%   11.48% 11.48% 11.48%    
Investment, Acquisition Date Mar. 21, 2025            
Investment Maturity Date Sep. 30, 2027   Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027    
Investment Owned, Balance, Principal Amount $ 124,000            
Investment Owned, at Cost 122,000            
Investment Owned, at Fair Value $ 113,000            
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  
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]  
Investment, Interest Rate, Floor   2.00%       2.00%  
Spread Above Index   7.00%       7.00%  
Investment Interest Rate   11.59%       11.59%  
Investment, Acquisition Date   Jul. 19, 2019          
Investment Maturity Date   Sep. 30, 2026       Sep. 30, 2026  
Investment Owned, Balance, Principal Amount   $ 247,000          
Investment Owned, at Cost   246,000          
Investment Owned, at Fair Value   $ 248,000          
Fair Value As A Percentage of Member's Equity   0.70%          
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.48% 10.90% 10.48% 10.48% 10.48% 10.90%  
Investment, Acquisition Date Sep. 13, 2024 Sep. 13, 2024          
Investment Maturity Date Sep. 30, 2027 Sep. 30, 2026 Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2026  
Investment Owned, Balance, Principal Amount $ 1,270,000 $ 480,000          
Investment Owned, at Cost 1,258,000 472,000          
Investment Owned, at Fair Value $ 1,187,000 $ 473,000          
Percent of net assets 0.50% 0.20% 0.50% 0.50% 0.50% 0.20%  
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]  
Investment, Interest Rate, Floor   2.00%       2.00%  
Spread Above Index   7.00%       7.00%  
Investment Interest Rate   11.59%       11.59%  
Investment, Acquisition Date   Jul. 19, 2019          
Investment Maturity Date   Sep. 30, 2026       Sep. 30, 2026  
Investment Owned, Balance, Principal Amount   $ 11,592,000          
Investment Owned, at Cost   11,563,000          
Investment Owned, at Fair Value   $ 11,592,000          
Fair Value As A Percentage of Member's Equity   33.50%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 7.50%   7.50% 7.50% 7.50%    
Investment Interest Rate 11.48%   11.48% 11.48% 11.48%    
Investment, Acquisition Date Jul. 19, 2019            
Investment Maturity Date Sep. 30, 2027   Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027    
Investment Owned, Balance, Principal Amount $ 288,000            
Investment Owned, at Cost 288,000            
Investment Owned, at Fair Value $ 262,000            
Fair Value As A Percentage of Member's Equity 0.80%            
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]    
Investment, Interest Rate, Floor 2.00%   2.00% 2.00% 2.00%    
Spread Above Index 7.50%   7.50% 7.50% 7.50%    
Investment Interest Rate 11.48%   11.48% 11.48% 11.48%    
Investment, Acquisition Date Jul. 19, 2019            
Investment Maturity Date Sep. 30, 2027   Sep. 30, 2027 Sep. 30, 2027 Sep. 30, 2027    
Investment Owned, Balance, Principal Amount $ 11,668,000            
Investment Owned, at Cost 11,655,000            
Investment Owned, at Fair Value $ 11,041,000            
Fair Value As A Percentage of Member's Equity 33.50%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.49% 9.99% 9.49% 9.49% 9.49% 9.99%  
Investment, Acquisition Date Jan. 27, 2021 Jan. 27, 2021          
Investment Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029  
Investment Owned, Balance, Principal Amount $ 2,916,000 $ 2,946,000          
Investment Owned, at Cost 2,898,000 2,922,000          
Investment Owned, at Fair Value $ 2,827,000 $ 2,946,000          
Fair Value As A Percentage of Member's Equity 8.60% 8.50%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.25%       5.25%  
Investment Interest Rate   9.99%       9.99%  
Investment, Acquisition Date   Jan. 27, 2021          
Investment Maturity Date   Jan. 02, 2029       Jan. 02, 2029  
Investment Owned, at 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.32% 9.73% 9.32% 9.32% 9.32% 9.73%  
Investment, Acquisition Date Jan. 27, 2021 Jan. 27, 2021          
Investment Maturity Date Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029  
Investment Owned, Balance, Principal Amount $ 10,809,000 $ 10,923,000          
Investment Owned, at Cost 10,747,000 10,839,000          
Investment Owned, at Fair Value $ 10,481,000 $ 10,923,000          
Fair Value As A Percentage of Member's Equity 31.90% 31.60%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.50%   5.50% 5.50% 5.50%    
Investment Interest Rate 9.49%   9.49% 9.49% 9.49%    
Investment, Acquisition Date Jan. 27, 2021            
Investment Maturity Date Jan. 02, 2029   Jan. 02, 2029 Jan. 02, 2029 Jan. 02, 2029    
Investment Owned, at Fair Value $ (35,000)            
Fair Value As A Percentage of Member's Equity (0.10%)            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.72% 10.71% 10.72% 10.72% 10.72% 10.71%  
Investment, Acquisition Date Jan. 23, 2024 Jan. 23, 2024          
Investment Maturity Date Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026 Dec. 31, 2026  
Investment Owned, Balance, Principal Amount $ 6,592,000 $ 6,659,000          
Investment Owned, at Cost 6,546,000 6,566,000          
Investment Owned, at Fair Value $ 6,396,000 $ 6,637,000          
Fair Value As A Percentage of Member's Equity 19.50% 19.20%          
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.76%   9.76% 9.76% 9.76%    
Investment, Acquisition Date Dec. 05, 2025            
Investment Maturity Date Dec. 05, 2031   Dec. 05, 2031 Dec. 05, 2031 Dec. 05, 2031    
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.82%   9.82% 9.82% 9.82%    
Investment, Acquisition Date Dec. 05, 2025            
Investment Maturity Date Dec. 05, 2031   Dec. 05, 2031 Dec. 05, 2031 Dec. 05, 2031    
Investment Owned, Balance, Principal Amount $ 638,000            
Investment Owned, at Cost 627,000            
Investment Owned, at Fair Value $ 627,000            
Percent of net assets 0.20%   0.20% 0.20% 0.20%    
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [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]    
Investment, Interest Rate, Floor 0.75%   0.75% 0.75% 0.75%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 9.76%   9.76% 9.76% 9.76%    
Investment, Acquisition Date Dec. 05, 2025            
Investment Maturity Date Dec. 05, 2031   Dec. 05, 2031 Dec. 05, 2031 Dec. 05, 2031    
Investment Owned, Balance, Principal Amount $ 10,213,000            
Investment Owned, at Cost 10,036,000            
Investment Owned, at Fair Value $ 10,034,000            
Percent of net assets 3.90%   3.90% 3.90% 3.90%    
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.97% 10.59% 9.97% 9.97% 9.97% 10.59%  
Investment, Acquisition Date Jun. 21, 2024 Jun. 21, 2024          
Investment Maturity Date Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029  
Investment Owned, at Fair Value $ 12,000 $ 9,000          
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 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.97% 10.59% 9.97% 9.97% 9.97% 10.59%  
Investment, Acquisition Date Jun. 21, 2024 Jun. 21, 2024          
Investment Maturity Date Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029 Jun. 21, 2029  
Investment Owned, Balance, Principal Amount $ 8,602,000 $ 8,756,000          
Investment Owned, at Cost 8,483,000 8,600,000          
Investment Owned, at 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, Identifier [Axis]: Ross-Simons Topco, LP Preferred Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Dec. 04, 2020 Dec. 04, 2020          
Investment Owned, Balance, Shares | shares 600 600 600 600 600 600  
Investment Owned, at Cost $ 514,000 $ 514,000          
Investment Owned, at Fair Value $ 735,000 $ 756,000          
Percent of net assets 0.30% 0.30% 0.30% 0.30% 0.30% 0.30%  
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Jun. 04, 2025            
Investment Maturity Date Mar. 28, 2031   Mar. 28, 2031 Mar. 28, 2031 Mar. 28, 2031    
Investment Owned, Balance, Principal Amount $ 295,000            
Investment Owned, at Cost 293,000            
Investment Owned, at Fair Value $ 319,000            
Fair Value As A Percentage of Member's Equity 1.00%            
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Jun. 04, 2025            
Investment Maturity Date Mar. 28, 2031   Mar. 28, 2031 Mar. 28, 2031 Mar. 28, 2031    
Investment Owned, at Fair Value $ 25,000            
Fair Value As A Percentage of Member's Equity 0.10%            
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Jun. 04, 2025            
Investment Maturity Date Mar. 28, 2031   Mar. 28, 2031 Mar. 28, 2031 Mar. 28, 2031    
Investment Owned, Balance, Principal Amount $ 9,090,000            
Investment Owned, at Cost 8,970,000            
Investment Owned, at Fair Value $ 9,142,000            
Fair Value As A Percentage of Member's Equity 27.80%            
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 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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 8.00%   8.00% 8.00% 8.00%    
Investment Interest Rate 11.82%   11.82% 11.82% 11.82%    
Investment, Acquisition Date Dec. 02, 2022            
Investment Maturity Date Dec. 02, 2027   Dec. 02, 2027 Dec. 02, 2027 Dec. 02, 2027    
Investment Owned, Balance, Principal Amount $ 1,652,000            
Investment Owned, at Cost 1,637,000            
Investment Owned, at Fair Value $ 1,653,000            
Percent of net assets 0.60%   0.60% 0.60% 0.60%    
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 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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 8.00%   8.00% 8.00% 8.00%    
Investment Interest Rate 11.82%   11.82% 11.82% 11.82%    
Investment, Acquisition Date Dec. 02, 2022            
Investment Maturity Date Dec. 02, 2027   Dec. 02, 2027 Dec. 02, 2027 Dec. 02, 2027    
Investment Owned, at Fair Value $ 8,000            
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 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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 8.00%   8.00% 8.00% 8.00%    
Investment Interest Rate 11.82%   11.82% 11.82% 11.82%    
Investment, Acquisition Date Dec. 02, 2022            
Investment Maturity Date Dec. 02, 2027   Dec. 02, 2027 Dec. 02, 2027 Dec. 02, 2027    
Investment Owned, Balance, Principal Amount $ 5,032,000            
Investment Owned, at Cost 4,974,000            
Investment Owned, at Fair Value $ 5,021,000            
Percent of net assets 1.90%   1.90% 1.90% 1.90%    
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 [Member]       Specialized Consumer Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.46%       12.46%  
Investment, Acquisition Date   Dec. 02, 2022          
Investment Maturity Date   Dec. 02, 2027       Dec. 02, 2027  
Investment Owned, Balance, Principal Amount   $ 1,669,000          
Investment Owned, at Cost   1,641,000          
Investment Owned, at Fair Value   $ 1,672,000          
Percent of net assets   0.60%       0.60%  
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member]       Specialized Consumer Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.46%       12.46%  
Investment, Acquisition Date   Dec. 02, 2022          
Investment Maturity Date   Dec. 02, 2027       Dec. 02, 2027  
Investment Owned, at Fair Value   $ 13,000          
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]       Specialized Consumer Services [Member]  
Investment, Variable Interest Rate, Type [Extensible Enumeration]   whfcl:SecuredOvernightFinancingRateMember       whfcl:SecuredOvernightFinancingRateMember  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   8.00%       8.00%  
Investment Interest Rate   12.46%       12.46%  
Investment, Acquisition Date   Dec. 02, 2022          
Investment Maturity Date   Dec. 02, 2027       Dec. 02, 2027  
Investment Owned, Balance, Principal Amount   $ 5,076,000          
Investment Owned, at Cost   4,988,000          
Investment Owned, at Fair Value   $ 5,063,000          
Percent of net assets   1.80%       1.80%  
Investment, Identifier [Axis]: Salon Republic Investments LLC, Common Stock              
Schedule of Investments [Line Items]              
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 [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member]  
Investment, Acquisition Date Dec. 02, 2022 Dec. 02, 2022          
Investment Owned, Balance, Shares | shares 400   400 400 400    
Investment Owned, Balance, Principal Amount   $ 400,000          
Investment Owned, at Cost $ 400,000 400,000          
Investment Owned, at Fair Value $ 6,000 $ 132,000          
Investment, Identifier [Axis]: Salon Republic Investments LLC, Preferred Stock              
Schedule of Investments [Line Items]              
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 [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member]  
Investment, Acquisition Date Dec. 02, 2022 Dec. 02, 2022          
Investment Owned, Balance, Shares | shares 200   200 200 200    
Investment Owned, Balance, Principal Amount   $ 200,000          
Investment Owned, at Cost $ 200,000 200,000          
Investment Owned, at Fair Value $ 265,000 $ 242,000          
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10% 0.10%  
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.37% 11.28% 9.37% 9.37% 9.37% 11.28%  
Investment, Acquisition Date Nov. 07, 2025 Oct. 12, 2021          
Investment Maturity Date Nov. 07, 2030 Oct. 12, 2026 Nov. 07, 2030 Nov. 07, 2030 Nov. 07, 2030 Oct. 12, 2026  
Investment Owned, at Fair Value   $ 5,000          
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.37% 11.28% 9.37% 9.37% 9.37% 11.28%  
Investment, Acquisition Date Nov. 07, 2025 Oct. 12, 2021          
Investment Maturity Date Nov. 07, 2030 Oct. 12, 2026 Nov. 07, 2030 Nov. 07, 2030 Nov. 07, 2030 Oct. 12, 2026  
Investment Owned, Balance, Principal Amount $ 13,455,000 $ 22,590,000          
Investment Owned, at Cost 13,259,000 22,401,000          
Investment Owned, at 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, 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.00%   6.00% 6.00% 6.00%    
Investment Interest Rate 7.90%   7.90% 7.90% 7.90%    
Investment, Acquisition Date May 04, 2022            
Investment Maturity Date Apr. 28, 2028   Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028    
Investment Owned, Balance, Principal Amount | €       € 6,198      
Investment Owned, at Cost $ 6,480,000            
Investment Owned, at Fair Value $ 7,281,000            
Fair Value As A Percentage of Member's Equity 22.10%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.57% 10.21% 9.57% 9.57% 9.57% 10.21%  
Investment, Acquisition Date May 04, 2022 May 04, 2022          
Investment Maturity Date Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028 Apr. 28, 2028  
Investment Owned, Balance, Principal Amount $ 944,000 $ 978,000          
Investment Owned, at Cost 936,000 967,000          
Investment Owned, at Fair Value $ 944,000 $ 978,000          
Fair Value As A Percentage of Member's Equity 2.90% 2.80%          
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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.00%       6.00%  
Investment Interest Rate   8.86%       8.86%  
Investment, Acquisition Date   May 04, 2022          
Investment Maturity Date   Apr. 28, 2028       Apr. 28, 2028  
Investment Owned, Balance, Principal Amount   $ 6,423,000          
Investment Owned, at Cost   6,682,000          
Investment Owned, at Fair Value   $ 6,654,000          
Fair Value As A Percentage of Member's Equity   19.20%          
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Class A Common Stock              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]  
Investment, Acquisition Date Jun. 29, 2020 Jun. 29, 2020          
Investment Owned, Balance, Shares | shares 2   2 2 2    
Investment Owned, Balance, Principal Amount   $ 2,000          
Investment Owned, at Cost $ 1,941,000 1,941,000          
Investment Owned, at Fair Value $ 507,000 $ 173,000          
Percent of net assets 0.20% 0.10% 0.20% 0.20% 0.20% 0.10%  
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc First Lien Secured Term Loan C              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]  
Investment, Acquisition Date Jun. 29, 2020 Jun. 29, 2020          
Investment Maturity Date Sep. 30, 2026   Sep. 30, 2026 Sep. 30, 2026 Sep. 30, 2026    
Investment Owned, Balance, Principal Amount $ 2,098,000 $ 1,822,000          
Investment Owned, at Cost 2,095,000 1,819,000          
Investment Owned, at Fair Value $ 2,098,000 $ 1,790,000          
Investment, Interest Rate, Paid in Kind 9.50%   9.50% 9.50% 9.50%    
Percent of net assets 0.80% 0.60% 0.80% 0.80% 0.80% 0.60%  
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Warrants              
Schedule of Investments [Line Items]              
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 [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member] Leisure Facilities [Member]  
Investment, Acquisition Date Jun. 29, 2020 Jun. 29, 2020          
Investment Owned, Balance, Shares | shares 1   1 1 1    
Investment Owned, Balance, Principal Amount   $ 1,000          
Investment Owned, at Cost $ 793,000 793,000          
Investment Owned, at Fair Value $ 205,000 $ 70,000          
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Aug. 10, 2021          
Investment Maturity Date   Jul. 30, 2027       Jul. 30, 2027  
Investment Owned, Balance, Principal Amount   $ 3,872,000          
Investment Owned, at Cost   3,839,000          
Investment Owned, at Fair Value   $ 3,854,000          
Fair Value As A Percentage of Member's Equity   11.10%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.96%       10.96%  
Investment, Acquisition Date   Aug. 10, 2021          
Investment Maturity Date   Jul. 30, 2027       Jul. 30, 2027  
Investment Owned, Balance, Principal Amount   $ 14,162,000          
Investment Owned, at Cost   14,041,000          
Investment Owned, at Fair Value   $ 14,095,000          
Fair Value As A Percentage of Member's Equity   40.70%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Aug. 10, 2021            
Investment Maturity Date Jul. 30, 2027   Jul. 30, 2027 Jul. 30, 2027 Jul. 30, 2027    
Investment Owned, Balance, Principal Amount $ 3,831,000            
Investment Owned, at Cost 3,811,000            
Investment Owned, at Fair Value $ 3,831,000            
Fair Value As A Percentage of Member's Equity 11.70%            
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.32%   10.32% 10.32% 10.32%    
Investment, Acquisition Date Aug. 10, 2021            
Investment Maturity Date Jul. 30, 2027   Jul. 30, 2027 Jul. 30, 2027 Jul. 30, 2027    
Investment Owned, Balance, Principal Amount $ 14,009,000            
Investment Owned, at Cost 13,935,000            
Investment Owned, at Fair Value $ 14,009,000            
Fair Value As A Percentage of Member's Equity 42.60%            
Investment, Identifier [Axis]: Sterling Pure Blocker, LLC (d/b/a Banner Industries, Inc.) Class B Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Dec. 01, 2023 Dec. 01, 2023          
Investment Owned, Balance, Shares | shares 404   404 404 404    
Investment Owned, Balance, Principal Amount   $ 404,000          
Investment Owned, at Cost $ 404,000 404,000          
Investment Owned, at Fair Value $ 57,000 $ 388,000          
Percent of net assets   0.10%       0.10%  
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.99% 10.46% 9.99% 9.99% 9.99% 10.46%  
Investment, Acquisition Date Sep. 06, 2024 Sep. 06, 2024          
Investment Maturity Date Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029  
Investment Owned, Balance, Principal Amount $ 1,002,000 $ 584,000          
Investment Owned, at Cost 987,000 573,000          
Investment Owned, at Fair Value $ 1,000,000 $ 577,000          
Percent of net assets 0.40% 0.20% 0.40% 0.40% 0.40% 0.20%  
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.82% 12.50% 10.82% 10.82% 10.82% 12.50%  
Investment, Acquisition Date Sep. 06, 2024 Sep. 06, 2024          
Investment Maturity Date Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029  
Investment Owned, Balance, Principal Amount $ 451,000 $ 585,000          
Investment Owned, at Cost 444,000 574,000          
Investment Owned, at Fair Value $ 450,000 $ 576,000          
Percent of net assets 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%  
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.99% 10.44% 9.99% 9.99% 9.99% 10.44%  
Investment, Acquisition Date Sep. 06, 2024 Sep. 06, 2024          
Investment Maturity Date Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029 Sep. 06, 2029  
Investment Owned, Balance, Principal Amount $ 5,679,000 $ 5,737,000          
Investment Owned, at Cost 5,596,000 5,629,000          
Investment Owned, at 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, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.92% 11.83% 10.92% 10.92% 10.92% 11.83%  
Investment, Acquisition Date Jun. 28, 2024 Jun. 28, 2024          
Investment Maturity Date Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029  
Investment Owned, Balance, Principal Amount $ 1,103,000            
Investment Owned, at Cost 1,084,000            
Investment Owned, at Fair Value $ 1,091,000 $ (1,000)          
Percent of net assets 0.40%   0.40% 0.40% 0.40%    
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.92% 11.83% 10.92% 10.92% 10.92% 11.83%  
Investment, Acquisition Date Jun. 28, 2024 Jun. 28, 2024          
Investment Maturity Date Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029  
Investment Owned, at Fair Value $ 1,000            
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing Services [Member] Transaction & Payment Processing 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 10.92% 11.83% 10.92% 10.92% 10.92% 11.83%  
Investment, Acquisition Date Jun. 28, 2024 Jun. 28, 2024          
Investment Maturity Date Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029 Jun. 28, 2029  
Investment Owned, Balance, Principal Amount $ 9,146,000 $ 8,239,000          
Investment Owned, at Cost 9,000,000 8,074,000          
Investment Owned, at 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, Identifier [Axis]: TVG I-EMSI Parent, LLC Class A Units              
Schedule of Investments [Line Items]              
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 [Member]   Education Services [Member] Education Services [Member] Education Services [Member]    
Investment, Acquisition Date Sep. 01, 2025            
Investment Owned, Balance, Principal Amount $ 20,765,000            
Investment, Identifier [Axis]: TVG I-EMSI Parent, LLC Class B Units              
Schedule of Investments [Line Items]              
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 [Member]   Education Services [Member] Education Services [Member] Education Services [Member]    
Investment, Acquisition Date Sep. 01, 2025            
Investment Owned, Balance, Principal Amount $ 2,000            
Investment Owned, at Cost 3,291,000            
Investment Owned, at Fair Value $ 3,291,000            
Percent of net assets 1.30%   1.30% 1.30% 1.30%    
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.57% 10.22% 9.57% 9.57% 9.57% 10.22%  
Investment, Acquisition Date Dec. 24, 2024 Dec. 24, 2024          
Investment Maturity Date Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028 Jun. 28, 2028  
Investment Owned, Balance, Principal Amount $ 2,480,000 $ 2,505,000          
Investment Owned, at Cost 2,453,000 2,468,000          
Investment Owned, at Fair Value $ 2,480,000 $ 2,468,000          
Fair Value As A Percentage of Member's Equity 7.50% 7.10%          
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment, Acquisition Date Jun. 07, 2025 Oct. 15, 2020          
Investment Maturity Date Jun. 07, 2028 Oct. 15, 2025 Jun. 07, 2028 Jun. 07, 2028 Jun. 07, 2028 Oct. 15, 2025  
Investment Owned, Balance, Principal Amount   $ 1,116,000          
Investment Owned, at Cost   1,051,000          
Investment Owned, at Fair Value $ 20,000 $ 1,009,000          
Investment, Interest Rate, Paid in Kind 10.19% 14.21% 10.19% 10.19% 10.19% 14.21%  
Percent of net assets   0.40%       0.40%  
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment, Acquisition Date Jun. 07, 2025 Oct. 15, 2020          
Investment Maturity Date Jun. 07, 2028 Oct. 15, 2025 Jun. 07, 2028 Jun. 07, 2028 Jun. 07, 2028 Oct. 15, 2025  
Investment Owned, Balance, Principal Amount $ 11,437,000 $ 18,547,000          
Investment Owned, at Cost 11,437,000 17,496,000          
Investment Owned, at Fair Value $ 11,437,000 $ 17,063,000          
Investment, Interest Rate, Paid in Kind 10.19% 14.21% 10.19% 10.19% 10.19% 14.21%  
Percent of net assets 4.40% 5.90% 4.40% 4.40% 4.40% 5.90%  
Investment, Identifier [Axis]: Telestream Topco 2 LLC (d/b/a Telestream Holdings Corporation) Common Units              
Schedule of Investments [Line Items]              
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    
Investment, Acquisition Date Jun. 07, 2025            
Investment Owned, Balance, Principal Amount $ 497,000            
Investment Owned, at Cost 7,109,000            
Investment Owned, at Fair Value $ 8,027,000            
Percent of net assets 3.10%   3.10% 3.10% 3.10%    
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.23%   10.23% 10.23% 10.23%    
Investment, Acquisition Date Nov. 26, 2025            
Investment Maturity Date Nov. 26, 2030   Nov. 26, 2030 Nov. 26, 2030 Nov. 26, 2030    
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.23%   10.23% 10.23% 10.23%    
Investment, Acquisition Date Nov. 26, 2025            
Investment Maturity Date Nov. 26, 2030   Nov. 26, 2030 Nov. 26, 2030 Nov. 26, 2030    
Investment Owned, Balance, Principal Amount $ 104,000            
Investment Owned, at Cost 100,000            
Investment Owned, at Fair Value $ 100,000            
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.23%   10.23% 10.23% 10.23%    
Investment, Acquisition Date Nov. 26, 2025            
Investment Maturity Date Nov. 26, 2030   Nov. 26, 2030 Nov. 26, 2030 Nov. 26, 2030    
Investment Owned, Balance, Principal Amount $ 11,128,000            
Investment Owned, at Cost 10,778,000            
Investment Owned, at Fair Value $ 10,776,000            
Percent of net assets 4.10%   4.10% 4.10% 4.10%    
Investment, Identifier [Axis]: Texas Express Wash, LLC Second Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member]    
Investment Interest Rate 14.00%   14.00% 14.00% 14.00%    
Investment, Acquisition Date Nov. 26, 2025            
Investment Maturity Date Nov. 26, 2031   Nov. 26, 2031 Nov. 26, 2031 Nov. 26, 2031    
Investment Owned, Balance, Principal Amount $ 1,569,000            
Investment Owned, at Cost 1,436,000            
Investment Owned, at Fair Value $ 1,435,000            
Investment, Interest Rate, Paid in Kind 7.00%   7.00% 7.00% 7.00%    
Investment, Interest Rate, Paid in Cash 7.00%   7.00% 7.00% 7.00%    
Percent of net assets 0.60%   0.60% 0.60% 0.60%    
Investment, Identifier [Axis]: Texas Wash Holdings, LLC (d/b/a ClearWater Express Wash) Warrants              
Schedule of Investments [Line Items]              
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 [Member]   Specialized Consumer Services [Member] Specialized Consumer Services [Member] Specialized Consumer Services [Member]    
Investment, Acquisition Date Nov. 26, 2025            
Investment Owned, at Cost $ 197,000            
Investment Owned, at Fair Value $ 197,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
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   Water Utilities Water Utilities Water Utilities    
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.90%   8.90% 8.90% 8.90%    
Investment, Acquisition Date Mar. 05, 2025            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, Balance, Principal Amount $ 802,000            
Investment Owned, at Cost 793,000            
Investment Owned, at Fair Value $ 806,000            
Fair Value As A Percentage of Member's Equity 2.50%            
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   Water Utilities Water Utilities Water Utilities    
Investment, Variable Interest Rate, Type [Extensible Enumeration] Base Rate [Member]   Base Rate [Member] Base Rate [Member] Base Rate [Member]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.84%   8.84% 8.84% 8.84%    
Investment, Acquisition Date Mar. 05, 2025            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, Balance, Principal Amount $ 312,000            
Investment Owned, at Cost 308,000            
Investment Owned, at Fair Value $ 317,000            
Fair Value As A Percentage of Member's Equity 1.00%            
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   Water Utilities Water Utilities Water Utilities    
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.00%   5.00% 5.00% 5.00%    
Investment Interest Rate 8.84%   8.84% 8.84% 8.84%    
Investment, Acquisition Date Mar. 05, 2025            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, Balance, Principal Amount $ 4,049,000            
Investment Owned, at Cost 3,998,000            
Investment Owned, at Fair Value $ 4,049,000            
Fair Value As A Percentage of Member's Equity 12.20%            
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.61% 10.97% 11.61% 11.61% 11.61% 10.97%  
Investment, Acquisition Date Apr. 05, 2021 Apr. 05, 2021          
Investment Maturity Date Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026  
Investment Owned, Balance, Principal Amount   $ 798,000          
Investment Owned, at Cost   795,000          
Investment Owned, at Fair Value $ (132,000) $ 761,000          
Investment, Interest Rate, Paid in Kind 1.00% 0.75% 1.00% 1.00% 1.00% 0.75%  
Investment, Interest Rate, Paid in Cash 10.61% 10.22% 10.61% 10.61% 10.61% 10.22%  
Percent of net assets (0.10%) 0.30% (0.10%) (0.10%) (0.10%) 0.30%  
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.61% 12.05% 11.61% 11.61% 11.61% 12.05%  
Investment, Acquisition Date Apr. 05, 2021 Apr. 05, 2021          
Investment Maturity Date Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026 Apr. 05, 2026  
Investment Owned, Balance, Principal Amount $ 11,409,000 $ 11,350,000          
Investment Owned, at Cost 11,400,000 11,309,000          
Investment Owned, at Fair Value $ 9,790,000 $ 10,895,000          
Investment, Interest Rate, Paid in Kind 1.00% 0.75% 1.00% 1.00% 1.00% 0.75%  
Investment, Interest Rate, Paid in Cash 10.61% 11.30% 10.61% 10.61% 10.61% 11.30%  
Percent of net assets 3.80% 3.80% 3.80% 3.80% 3.80% 3.80%  
Investment, Identifier [Axis]: Token Buyer, Inc First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.99% 10.74% 9.99% 9.99% 9.99% 10.74%  
Investment, Acquisition Date May 26, 2022 May 26, 2022          
Investment Maturity Date May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029  
Investment Owned, Balance, Principal Amount $ 1,587,000 $ 7,070,000          
Investment Owned, at Cost 1,363,000 6,709,000          
Investment Owned, at 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, Identifier [Axis]: Trailhead Media LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.17% 9.82% 9.17% 9.17% 9.17% 9.82%  
Investment, Acquisition Date Jan. 22, 2025 Dec. 30, 2024          
Investment Maturity Date Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029  
Investment Owned, at Fair Value $ (3,000)            
Investment, Interest Rate, Paid in Kind 0.75% 0.75% 0.75% 0.75% 0.75% 0.75%  
Investment, Interest Rate, Paid in Cash 8.42% 9.07% 8.42% 8.42% 8.42% 9.07%  
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.17% 9.82% 9.17% 9.17% 9.17% 9.82%  
Investment, Acquisition Date Jan. 22, 2025 Dec. 30, 2024          
Investment Maturity Date Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029  
Investment Owned, at Fair Value $ (3,000)            
Investment, Interest Rate, Paid in Kind 0.75% 0.75% 0.75% 0.75% 0.75% 0.75%  
Investment, Interest Rate, Paid in Cash 8.42% 9.07% 8.42% 8.42% 8.42% 9.07%  
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.17% 9.82% 9.17% 9.17% 9.17% 9.82%  
Investment, Acquisition Date Jan. 22, 2025 Dec. 30, 2024          
Investment Maturity Date Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029 Dec. 28, 2029  
Investment Owned, Balance, Principal Amount $ 6,632,000 $ 6,648,000          
Investment Owned, at Cost 6,553,000 6,548,000          
Investment Owned, at Fair Value $ 6,532,000 $ 6,548,000          
Investment, Interest Rate, Paid in Kind 0.75% 0.75% 0.75% 0.75% 0.75% 0.75%  
Investment, Interest Rate, Paid in Cash 8.42% 9.07% 8.42% 8.42% 8.42% 9.07%  
Fair Value As A Percentage of Member's Equity 19.90%            
Percent of net assets   2.30%       2.30%  
Investment, Identifier [Axis]: Transervice Holdings, Inc. (d/b/a Transervice Logistics, Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.07% 11.71% 11.07% 11.07% 11.07% 11.71%  
Investment, Acquisition Date Jun. 29, 2023 Jun. 29, 2023          
Investment Maturity Date Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028 Jun. 29, 2028  
Investment Owned, Balance, Principal Amount $ 7,701,000 $ 8,663,000          
Investment Owned, at Cost 7,586,000 8,481,000          
Investment Owned, at 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, Identifier [Axis]: Trimlite Buyer LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.08% 9.99% 8.08% 8.08% 8.08% 9.99%  
Investment, Acquisition Date Jul. 27, 2021 Jul. 27, 2021          
Investment Maturity Date Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027 Jul. 27, 2027  
Investment Owned, Balance, Principal Amount     $ 18,868     $ 18,984  
Investment Owned, at Cost     $ 14,957     15,006  
Investment Owned, at Fair Value $ 13,748,000         $ 13,206  
Percent of net assets 5.30% 4.60% 5.30% 5.30% 5.30% 4.60%  
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.50%       5.50%  
Investment Interest Rate   9.83%       9.83%  
Investment, Acquisition Date   Jun. 14, 2024          
Investment Maturity Date   May 31, 2029       May 31, 2029  
Investment Owned, at 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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.92% 9.83% 8.92% 8.92% 8.92% 9.83%  
Investment, Acquisition Date Jun. 14, 2024 Jun. 14, 2024          
Investment Maturity Date May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029  
Investment Owned, at Fair Value $ 18,000 $ 12,000          
Fair Value As A Percentage of Member's Equity 0.10%            
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]  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.92% 9.83% 8.92% 8.92% 8.92% 9.83%  
Investment, Acquisition Date Jun. 14, 2024 Jun. 14, 2024          
Investment Maturity Date May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029 May 31, 2029  
Investment Owned, Balance, Principal Amount $ 8,093,000 $ 5,349,000          
Investment Owned, at Cost 7,975,000 5,254,000          
Investment Owned, at Fair Value $ 8,107,000 $ 5,338,000          
Fair Value As A Percentage of Member's Equity 24.70% 15.40%          
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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.21%       10.21%  
Investment, Acquisition Date   Aug. 10, 2021          
Investment Maturity Date   Sep. 02, 2026       Sep. 02, 2026  
Investment Owned, at 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]  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   5.75%       5.75%  
Investment Interest Rate   10.21%       10.21%  
Investment, Acquisition Date   Aug. 10, 2021          
Investment Maturity Date   Sep. 02, 2026       Sep. 02, 2026  
Investment Owned, Balance, Principal Amount   $ 5,964,000          
Investment Owned, at Cost   5,924,000          
Investment Owned, at Fair Value   $ 5,964,000          
Fair Value As A Percentage of Member's Equity   17.20%          
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.57%   9.57% 9.57% 9.57%    
Investment, Acquisition Date Aug. 10, 2021            
Investment Maturity Date Mar. 02, 2028   Mar. 02, 2028 Mar. 02, 2028 Mar. 02, 2028    
Investment Owned, at 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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 5.75%   5.75% 5.75% 5.75%    
Investment Interest Rate 9.57%   9.57% 9.57% 9.57%    
Investment, Acquisition Date Aug. 10, 2021            
Investment Maturity Date Mar. 02, 2028   Mar. 02, 2028 Mar. 02, 2028 Mar. 02, 2028    
Investment Owned, Balance, Principal Amount $ 5,902,000            
Investment Owned, at Cost 5,885,000            
Investment Owned, at Fair Value $ 5,902,000            
Fair Value As A Percentage of Member's Equity 18.00%            
Investment, Identifier [Axis]: Twin Ridge CRS, LP (d/b/a CRS OneSource) Class A Common Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date May 10, 2024 May 10, 2024          
Investment Owned, Balance, Shares | shares 63   63 63 63    
Investment Owned, Balance, Principal Amount   $ 63,000          
Investment Owned, at Cost $ 317,000 317,000          
Investment Owned, at Fair Value $ 264,000 $ 350,000          
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10% 0.10%  
Investment, Identifier [Axis]: UserZoom Technologies, Inc. First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 11.63% 12.75% 11.63% 11.63% 11.63% 12.75%  
Investment, Acquisition Date Jan. 12, 2023 Jan. 12, 2023          
Investment Maturity Date Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029 Apr. 05, 2029  
Investment Owned, Balance, Principal Amount $ 9,819,000 $ 9,819,000          
Investment Owned, at Cost 9,665,000 9,618,000          
Investment Owned, at 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, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Preferred Units              
Schedule of Investments [Line Items]              
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    
Investment, Acquisition Date Apr. 10, 2023            
Investment Owned, at Fair Value $ 15,000            
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Series A Units              
Schedule of Investments [Line Items]              
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  
Investment, Acquisition Date Apr. 10, 2023 Apr. 10, 2023          
Investment Owned, at Cost   $ 314,000          
Investment Owned, at Fair Value $ 308,000 $ 493,000          
Percent of net assets 0.10% 0.20% 0.10% 0.10% 0.10% 0.20%  
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 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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.86%       10.86%  
Investment, Acquisition Date   Aug. 15, 2024          
Investment Maturity Date   Aug. 15, 2029       Aug. 15, 2029  
Investment Owned, at Fair Value   $ 9,000          
Investment, Interest Rate, Paid in Kind   1.00%       1.00%  
Investment, Interest Rate, Paid in Cash   9.86%       9.86%  
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 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  
Investment, Interest Rate, Floor   1.00%       1.00%  
Spread Above Index   6.50%       6.50%  
Investment Interest Rate   10.86%       10.86%  
Investment, Acquisition Date   Aug. 15, 2024          
Investment Maturity Date   Aug. 15, 2029       Aug. 15, 2029  
Investment Owned, Balance, Principal Amount   $ 12,322,000          
Investment Owned, at Cost   12,124,000          
Investment Owned, at Fair Value   $ 12,216,000          
Investment, Interest Rate, Paid in Kind   1.00%       1.00%  
Investment, Interest Rate, Paid in Cash   9.86%       9.86%  
Percent of net assets   4.30%       4.30%  
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 6.50%   6.50% 6.50% 6.50%    
Investment Interest Rate 10.22%   10.22% 10.22% 10.22%    
Investment, Acquisition Date Aug. 15, 2024            
Investment Maturity Date Aug. 15, 2029   Aug. 15, 2029 Aug. 15, 2029 Aug. 15, 2029    
Investment Owned, Balance, Principal Amount $ 12,308,000            
Investment Owned, at Cost 12,154,000            
Investment Owned, at Fair Value $ 12,334,000            
Investment, Interest Rate, Paid in Kind 1.00%   1.00% 1.00% 1.00%    
Investment, Interest Rate, Paid in Cash 9.22%   9.22% 9.22% 9.22%    
Percent of net assets 4.70%   4.70% 4.70% 4.70%    
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]    
Investment, Interest Rate, Floor 1.00%   1.00% 1.00% 1.00%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.47%   8.47% 8.47% 8.47%    
Investment, Acquisition Date Apr. 01, 2025            
Investment Maturity Date Apr. 10, 2031   Apr. 10, 2031 Apr. 10, 2031 Apr. 10, 2031    
Investment Owned, Balance, Principal Amount $ 6,948,000            
Investment Owned, at Cost 6,918,000            
Investment Owned, at Fair Value $ 6,948,000            
Fair Value As A Percentage of Member's Equity 21.10%            
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  
Investment Owned, at 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 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 [Member] Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [Member]  
Investment, Acquisition Date Jul. 19, 2019 Jul. 19, 2019          
Investment Owned, Balance, Shares | shares 21,104   21,104 21,104 21,104    
Investment Owned, Balance, Principal Amount   $ 21,104,000          
Investment Owned, at Cost $ 21,104,000 21,104,000          
Investment Owned, at 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, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Subordinated Note              
Schedule of Investments [Line Items]              
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 [Member] Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [Member] Specialized Finance [Member]  
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  
Investment, Acquisition Date Jul. 19, 2019 Jul. 19, 2019          
Investment Owned, Balance, Principal Amount $ 84,416,000 $ 84,416,000          
Investment Owned, at Cost 84,416,000 84,416,000          
Investment Owned, at 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, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Delayed Draw Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.92% 10.58% 9.92% 9.92% 9.92% 10.58%  
Investment, Acquisition Date Aug. 01, 2024 Aug. 01, 2024          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, at Fair Value $ 1,000 $ 2,000          
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Revolving Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.92% 10.58% 9.92% 9.92% 9.92% 10.58%  
Investment, Acquisition Date Aug. 01, 2024 Aug. 01, 2024          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, Balance, Principal Amount $ 345,000 $ 258,000          
Investment Owned, at Cost 340,000 253,000          
Investment Owned, at Fair Value $ 346,000 $ 254,000          
Percent of net assets 0.10% 0.10% 0.10% 0.10% 0.10% 0.10%  
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 9.92% 10.58% 9.92% 9.92% 9.92% 10.58%  
Investment, Acquisition Date Aug. 01, 2024 Aug. 01, 2024          
Investment Maturity Date Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029 Aug. 01, 2029  
Investment Owned, Balance, Principal Amount $ 7,148,000 $ 7,689,000          
Investment Owned, at Cost 7,045,000 7,548,000          
Investment Owned, at 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, Identifier [Axis]: What If Media Group, LLC Common Units              
Schedule of Investments [Line Items]              
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 And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member]  
Investment, Acquisition Date Jul. 02, 2021 Jul. 02, 2021          
Investment Owned, Balance, Shares | shares 3,081   3,081 3,081 3,081    
Investment Owned, Balance, Principal Amount   $ 3,081,000          
Investment Owned, at Cost $ 851,000 851,000          
Investment Owned, at 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, Identifier [Axis]: Whitestone Home Furnishings, LLC (d/b/a Saatva, Inc.) First Lien Secured Term Loan              
Schedule of Investments [Line Items]              
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 [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member] Home Furnishings [Member]  
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  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.97% 10.46% 8.97% 8.97% 8.97% 10.46%  
Investment, Acquisition Date Nov. 06, 2023 Nov. 06, 2023          
Investment Maturity Date Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026 Aug. 20, 2026  
Investment Owned, Balance, Principal Amount $ 2,848,000 $ 2,930,000          
Investment Owned, at Cost 2,832,000 2,887,000          
Investment Owned, at 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, 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 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 And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And 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  
Investment, Interest Rate, 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%  
Investment Interest Rate 8.42% 10.83% 8.42% 8.42% 8.42% 10.83%  
Investment, Acquisition Date Jan. 31, 2024 Jan. 31, 2024          
Investment Maturity Date Jan. 31, 2031 Jan. 31, 2030 Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2030  
Investment Owned, at Fair Value $ 32,000 $ 48,000          
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 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 And Services [Member]   Interactive Media And Services [Member] Interactive Media And Services [Member] Interactive Media And Services [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]    
Investment, Interest Rate, Floor 0.50%   0.50% 0.50% 0.50%    
Spread Above Index 4.75%   4.75% 4.75% 4.75%    
Investment Interest Rate 8.42%   8.42% 8.42% 8.42%    
Investment, Acquisition Date Jan. 31, 2024            
Investment Maturity Date Jan. 31, 2031   Jan. 31, 2031 Jan. 31, 2031 Jan. 31, 2031    
Investment Owned, Balance, Principal Amount $ 13,945,000            
Investment Owned, at Cost 13,701,000            
Investment Owned, at Fair Value $ 13,945,000            
Percent of net assets 5.40%   5.40% 5.40% 5.40%    
Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 532,286,000 631,941,000          
Investment Owned, at Fair Value $ 520,114,000 $ 596,626,000          
Percent of net assets 200.20% 208.40% 200.20% 200.20% 200.20% 208.40%  
Money Market Funds              
Schedule of Investments [Line Items]              
Money Market Funds amortized cost $ 21,048,000 $ 13,249,000          
Money Market Fair Value $ 21,048,000 $ 13,249,000          
Percent of net assets 8.10% 4.60% 8.10% 8.10% 8.10% 4.60%  
Money Market Funds | STRS JV              
Schedule of Investments [Line Items]              
Money Market Funds amortized cost $ 5,882,000 $ 767,000          
Money Market Fair Value $ 5,882,000 $ 767,000          
Percent of net assets 17.90% 2.20% 17.90% 17.90% 17.90% 2.20%  
Goldman Sachs Money Market Fund (CUSIP: 38141W315)              
Schedule of Investments [Line Items]              
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          
Percent of net assets 3.40% 0.30% 3.40% 3.40% 3.40% 0.30%  
Goldman Sachs Money Market Fund (CUSIP: 38141W315) | STRS JV              
Schedule of Investments [Line Items]              
Weighted average interest rate 3.34% 4.33% 3.34% 3.34% 3.34% 4.33%  
Money Market Funds amortized cost $ 2,602,000 $ 242,000          
Money Market Fair Value $ 2,602,000 $ 242,000          
Percent of net assets 7.90% 0.70% 7.90% 7.90% 7.90% 0.70%  
JPMORGAN U.S. Treas Plus Money Market Fund | STRS JV              
Schedule of Investments [Line Items]              
Weighted average interest rate 3.65% 4.39% 3.65% 3.65% 3.65% 4.39%  
Money Market Funds amortized cost $ 3,279,000 $ 525,000          
Money Market Fair Value $ 3,279,000 $ 525,000          
Percent of net assets 10.00% 1.50% 10.00% 10.00% 10.00% 1.50%  
Invesco Treasury Money Market Fund (CUSIP: 825252406)              
Schedule of Investments [Line Items]              
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          
Percent of net assets 2.70% 4.30% 2.70% 2.70% 2.70% 4.30%  
Advertising | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 19,031,000 $ 11,937,000          
Investment Owned, at Fair Value $ 19,052,000 $ 12,035,000          
Fair Value As A Percentage of Member's Equity 58.00% 34.80%          
Advertising | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 1,191,000 $ 16,365,000          
Investment Owned, at Fair Value $ 1,196,000 $ 16,862,000          
Percent of net assets 0.50% 6.00% 0.50% 0.50% 0.50% 6.00%  
Air Freight & Logistics | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 3,262,000 $ 3,286,000          
Investment Owned, at Fair Value $ 3,273,000 $ 3,311,000          
Fair Value As A Percentage of Member's Equity 10.00% 9.60%          
Air Freight & Logistics | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 30,732,000 $ 29,360,000          
Investment Owned, at Fair Value $ 30,754,000 $ 28,518,000          
Percent of net assets 11.70% 9.90% 11.70% 11.70% 11.70% 9.90%  
Asset Management & Custody Banks | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 8,881,000            
Investment Owned, at Fair Value $ 9,074,000            
Fair Value As A Percentage of Member's Equity 27.60%            
Aerospace & Defense | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost   $ 3,633,000          
Investment Owned, at Fair Value   $ 3,682,000          
Fair Value As A Percentage of Member's Equity   10.60%          
Application Software | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 22,062,000 $ 36,508,000          
Investment Owned, at Fair Value $ 20,888,000 $ 26,924,000          
Percent of net assets 8.00% 9.40% 8.00% 8.00% 8.00% 9.40%  
Broadline Retail | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 18,019,000 $ 18,577,000          
Investment Owned, at Fair Value $ 17,260,000 $ 17,827,000          
Fair Value As A Percentage of Member's Equity 52.50% 51.50%          
Broadline Retail | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost   $ 4,556,000          
Investment Owned, at Fair Value   $ 4,580,000          
Percent of net assets   1.60%       1.60%  
Building Products | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 22,594,000 $ 13,445,000          
Investment Owned, at Fair Value $ 22,800,000 $ 13,437,000          
Fair Value As A Percentage of Member's Equity 69.40% 38.80%          
Building Products | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 14,957,000         $ 15,006  
Investment Owned, at Fair Value $ 13,748,000         $ 13,206  
Percent of net assets 5.30% 4.60% 5.30% 5.30% 5.30% 4.60%  
Commodity Chemicals | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 6,918,000            
Investment Owned, at Fair Value $ 6,948,000            
Fair Value As A Percentage of Member's Equity 21.10%            
Commodity Chemicals | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost   $ 15,765,000          
Investment Owned, at Fair Value   $ 16,026,000          
Percent of net assets   5.60%       5.60%  
Construction & Engineering | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 18,386,000 $ 16,016,000          
Investment Owned, at Fair Value $ 18,284,000 $ 16,253,000          
Fair Value As A Percentage of Member's Equity 55.70% 47.00%          
Construction & Engineering | Debt Investments              
Schedule of Investments [Line Items]              
Investment, Issuer Geographic Region [Extensible Enumeration]   srt:NorthAmericaMember       srt:NorthAmericaMember  
Investment Owned, at Cost $ 9,736,000 $ 3,539,000          
Investment Owned, at Fair Value $ 9,849,000 $ 3,539,000          
Percent of net assets 3.80% 1.20% 3.80% 3.80% 3.80% 1.20%  
Data Processing & Outsourced Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost   $ 14,234,000          
Investment Owned, at Fair Value   $ 12,885,000          
Fair Value As A Percentage of Member's Equity   37.20%          
Data Processing & Outsourced Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 26,661,000 $ 28,409,000          
Investment Owned, at Fair Value $ 26,789,000 $ 28,572,000          
Percent of net assets 10.30% 10.00% 10.30% 10.30% 10.30% 10.00%  
Diversified Support Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 24,227,000 $ 19,107,000          
Investment Owned, at Fair Value $ 23,644,000 $ 19,282,000          
Fair Value As A Percentage of Member's Equity 71.80% 55.70%          
Diversified Support Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 9,440,000 $ 9,559,000          
Investment Owned, at Fair Value $ 9,337,000 $ 9,414,000          
Percent of net assets 3.60% 3.30% 3.60% 3.60% 3.60% 3.30%  
Electrical Components & Equipment | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 9,298,000 $ 3,479,000          
Investment Owned, at Fair Value $ 9,332,000 $ 3,479,000          
Fair Value As A Percentage of Member's Equity 28.40% 10.10%          
Environmental & Facilities Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 29,460,000 $ 29,529,000          
Investment Owned, at Fair Value $ 29,529,000 $ 29,963,000          
Fair Value As A Percentage of Member's Equity 90.00% 86.60%          
Environmental & Facilities Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 1,568,000            
Investment Owned, at Fair Value $ 1,610,000            
Percent of net assets 0.70%   0.70% 0.70% 0.70%    
Health Care Facilities | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 13,327,000 $ 7,944,000          
Investment Owned, at Fair Value $ 13,387,000 $ 8,004,000          
Fair Value As A Percentage of Member's Equity 40.70% 23.10%          
Health Care Facilities | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 4,534,000 $ 8,694,000          
Investment Owned, at Fair Value $ 4,623,000 $ 8,660,000          
Percent of net assets 1.80% 3.00% 1.80% 1.80% 1.80% 3.00%  
Health Care Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 4,872,000 $ 4,898,000          
Investment Owned, at Fair Value $ 4,982,000 $ 4,995,000          
Fair Value As A Percentage of Member's Equity 15.10% 14.40%          
Health Care Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 8,315,000 $ 19,577,000          
Investment Owned, at Fair Value $ 8,389,000 $ 19,589,000          
Percent of net assets 3.20% 6.90% 3.20% 3.20% 3.20% 6.90%  
Health Care Supplies | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost   $ 7,461,000          
Investment Owned, at Fair Value   $ 7,696,000          
Fair Value As A Percentage of Member's Equity   22.20%          
Health Care Supplies | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 20,227,000 $ 20,142,000          
Investment Owned, at Fair Value $ 20,026,000 $ 19,535,000          
Percent of net assets 7.70% 6.80% 7.70% 7.70% 7.70% 6.80%  
Health Care Technology | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 4,132,000            
Investment Owned, at Fair Value $ 4,183,000            
Fair Value As A Percentage of Member's Equity 12.70%            
Human Resource & Employment Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 2,484,000            
Investment Owned, at Fair Value $ 2,493,000            
Fair Value As A Percentage of Member's Equity 7.60%            
Human Resource & Employment Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 2,899,000            
Investment Owned, at Fair Value $ 2,909,000            
Percent of net assets 1.10%   1.10% 1.10% 1.10%    
Household Appliances | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 7,416,000 $ 7,649,000          
Investment Owned, at Fair Value $ 8,225,000 $ 7,632,000          
Fair Value As A Percentage of Member's Equity 25.00% 22.00%          
Household Appliances | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 1,363,000 $ 22,326,000          
Investment Owned, at Fair Value $ 1,199,000 $ 21,255,000          
Percent of net assets 0.50% 7.40% 0.50% 0.50% 0.50% 7.40%  
Household Products | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 10,293,000            
Investment Owned, at Fair Value $ 10,384,000            
Fair Value As A Percentage of Member's Equity 31.60%            
Household Products | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 11,400,000 $ 12,104,000          
Investment Owned, at Fair Value $ 9,658,000 $ 11,656,000          
Percent of net assets 3.70% 4.10% 3.70% 3.70% 3.70% 4.10%  
Industrial Machinery & Supplies & Components | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 12,154,000 $ 12,124,000          
Investment Owned, at Fair Value $ 12,334,000 $ 12,225,000          
Percent of net assets 4.70% 4.30% 4.70% 4.70% 4.70% 4.30%  
IT Consulting And Other Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 35,186,000 $ 32,427,000          
Investment Owned, at Fair Value $ 34,895,000 $ 32,720,000          
Fair Value As A Percentage of Member's Equity 106.20% 94.60%          
IT Consulting And Other Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 281,000            
Investment Owned, at Fair Value $ 300,000            
Percent of net assets 0.10%   0.10% 0.10% 0.10%    
Leisure Products | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 25,612,000 $ 45,674,000          
Investment Owned, at Fair Value $ 23,767,000 $ 23,298,000          
Percent of net assets 9.20% 8.10% 9.20% 9.20% 9.20% 8.10%  
Packaged Foods & Meats | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 6,867,000 $ 6,939,000          
Investment Owned, at Fair Value $ 6,961,000 $ 7,009,000          
Fair Value As A Percentage of Member's Equity 21.00% 20.20%          
Packaged Foods & Meats | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 3,973,000 $ 4,024,000          
Investment Owned, at Fair Value $ 4,033,000 $ 4,087,000          
Percent of net assets 1.60% 1.40% 1.60% 1.60% 1.60% 1.40%  
Paper & Plastic Packaging Products & Materials | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 14,694,000 $ 14,964,000          
Investment Owned, at Fair Value $ 14,729,000 $ 14,881,000          
Fair Value As A Percentage of Member's Equity 44.70% 43.20%          
Personal Products | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 3,850,000            
Investment Owned, at Fair Value $ 3,887,000            
Fair Value As A Percentage of Member's Equity 11.70%            
Pharmaceuticals | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost   $ 16,411,000          
Investment Owned, at Fair Value   $ 15,461,000          
Fair Value As A Percentage of Member's Equity   44.70%          
Pharmaceuticals | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 12,031,000            
Investment Owned, at Fair Value $ 12,027,000            
Percent of net assets 4.70%   4.70% 4.70% 4.70%    
Real Estate Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 12,651,000 $ 14,554,000          
Investment Owned, at Fair Value $ 12,139,000 $ 13,782,000          
Fair Value As A Percentage of Member's Equity 36.90% 39.80%          
Research & Consulting Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 3,890,000 $ 11,900,000          
Investment Owned, at Fair Value $ 3,859,000 $ 11,977,000          
Fair Value As A Percentage of Member's Equity 11.70% 34.60%          
Research & Consulting Services | Debt Investments              
Schedule of Investments [Line Items]              
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Investment Owned, at Cost $ 4,748,000 $ 4,823,000          
Investment Owned, at Fair Value $ 4,831,000 $ 4,927,000          
Percent of net assets 1.90% 1.70% 1.90% 1.90% 1.90% 1.70%  
Systems Software | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 18,657,000 $ 16,573,000          
Investment Owned, at Fair Value $ 19,360,000 $ 17,267,000          
Percent of net assets 7.50% 5.90% 7.50% 7.50% 7.50% 5.90%  
Technology Hardware, Storage & Peripherals | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 17,746,000 $ 17,880,000          
Investment Owned, at Fair Value $ 17,840,000 $ 17,949,000          
Fair Value As A Percentage of Member's Equity 54.30% 51.80%          
Technology Hardware, Storage & Peripherals | Debt Investments              
Schedule of Investments [Line Items]              
Investment, Type [Extensible Enumeration]   First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Investment Owned, at Cost $ 11,437,000 $ 18,547,000          
Investment Owned, at Fair Value $ 11,457,000 $ 18,072,000          
Percent of net assets 4.40% 6.30% 4.40% 4.40% 4.40% 6.30%  
Water Utilities | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 5,099,000            
Investment Owned, at Fair Value $ 5,172,000            
Fair Value As A Percentage of Member's Equity 15.70%            
Distributors | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 9,911,000 $ 9,307,000          
Investment Owned, at Fair Value $ 9,992,000 $ 9,372,000          
Fair Value As A Percentage of Member's Equity 30.30% 27.10%          
Distributors | Debt Investments              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 10,243,000 $ 10,563,000          
Investment Owned, at Fair Value $ 10,404,000 $ 10,690,000          
Percent of net assets 3.90% 3.70% 3.90% 3.90% 3.90% 3.70%  
Food Distributors | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 4,889,000 $ 4,919,000          
Investment Owned, at Fair Value $ 4,928,000 $ 4,993,000          
Fair Value As A Percentage of Member's Equity 15.00% 14.40%          
Wireless Telecommunication Services | STRS JV              
Schedule of Investments [Line Items]              
Investment Owned, at Cost $ 6,218,000 $ 6,256,000          
Investment Owned, at Fair Value $ 6,300,000 $ 6,332,000          
Fair Value As A Percentage of Member's Equity 19.10% 18.30%