v3.25.1
INVESTMENTS - Affiliated and Controlled Persons (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Jun. 30, 2023
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Sep. 30, 2024
Mar. 31, 2023
Investments in and Advances to Affiliates [Line Items]            
Weighted average remaining term of debt investments   3 years 2 years 9 months 18 days      
Cost basis of non-accrual loans   $ 69,576 $ 38,322      
Fair value of non-accrual loans   37,019 14,087      
Cost of investment   695,240 740,021      
Paydown received under investments   186,251 128,199 $ 239,622    
Schedule of investments in and advances to affiliated and controlled persons            
Beginning Fair Value   696,168        
Net Change in Unrealized Appreciation (Depreciation)   (9,567) (21,969) (9,191)    
Ending Fair Value   642,213 696,168      
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 78        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AbCentersAcquisitionCorporationMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 80        
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AbCentersAcquisitionCorporationMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 5        
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,866        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AbCentersAcquisitionCorporationMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 7,919        
Investment, Identifier [Axis]: ABB/Con-cise Optical Group LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 20,142 $ 20,056      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ABBCon-ciseOpticalGroupLLCMember whfcl:ABBCon-ciseOpticalGroupLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 18,983        
Ending Fair Value   19,535 $ 18,983      
Investment, Identifier [Axis]: ALM Media, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 12,555      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ALMMediaLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 12,517        
Ending Fair Value     $ 12,517      
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ApgLionsPurchaserLlcMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 15        
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ApgLionsPurchaserLlcMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 6        
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,027        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ApgLionsPurchaserLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 4,070        
Investment, Identifier [Axis]: ATSG, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 9,678      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ATSGIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   9,771        
Ending Fair Value     $ 9,771      
Investment, Identifier [Axis]: ATSG, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 3,741      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ATSGIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   3,745        
Ending Fair Value     $ 3,745      
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,615        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AlvariaHoldcoMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 1,456        
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan Four            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,330        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AlvariaHoldcoMember        
Investment type   whfcl:SecondLienSecuredTermLoanMember        
Ending Fair Value   $ 74        
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan Three            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,318        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AlvariaHoldcoMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 3,990        
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan Two            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,029        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AlvariaHoldcoMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 451        
Investment, Identifier [Axis]: American Crafts Holdings, LLC, Warrants            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsHoldingsLlcMember whfcl:AmericanCraftsHoldingsLlcMember      
Investment type   Warrant Warrant      
Investment, Identifier [Axis]: American Crafts LC Super Priority First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,094 $ 1,903      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember      
Investment type   whfcl:SuperPriorityFirstLienSecuredTermLoanMember whfcl:SuperPriorityFirstLienSecuredTermLoanMember      
Beginning Fair Value   $ 1,878        
Ending Fair Value     $ 1,878      
Investment, Identifier [Axis]: American Crafts Lc Super Priority First Lien Secured Term Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember      
Investment type   whfcl:SuperPriorityFirstLienSecuredTermLoanMember whfcl:SuperPriorityFirstLienSecuredTermLoanMember      
Dividends, interest and PIK included in income   $ 187 $ 109      
Beginning Fair Value   1,878        
Gross Additions   191 1,903      
Net Change in Unrealized Appreciation (Depreciation)   (2,069) (25)      
Ending Fair Value     1,878      
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,458 $ 1,458      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Dividends, interest and PIK included in income     $ 95      
Beginning Fair Value   $ 93        
Gross Additions     1,259      
Net Change in Unrealized Appreciation (Depreciation)   (93) (1,166)      
Ending Fair Value     93      
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,720 $ 8,720      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Dividends, interest and PIK included in income     $ 568      
Beginning Fair Value   $ 553        
Gross Additions     7,491      
Net Change in Unrealized Appreciation (Depreciation)   (553) (6,938)      
Ending Fair Value     553      
Investment, Identifier [Axis]: American Crafts, LC Priority First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,105 $ 5,105      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember      
Investment type   whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember      
Dividends, interest and PIK included in income   $ 10 $ 575      
Beginning Fair Value   3,226        
Gross Additions     5,105      
Net Change in Unrealized Appreciation (Depreciation)   (3,226) (1,879)      
Ending Fair Value     $ 3,226      
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,374        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember        
Investment type   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember        
Dividends, interest and PIK included in income   $ 107        
Gross Additions   2,374        
Net Change in Unrealized Appreciation (Depreciation)   (2,001)        
Ending Fair Value   373        
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan One            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,230        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember        
Investment type   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember        
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan one            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:AmericanCraftsLCMember        
Investment type   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember        
Dividends, interest and PIK included in income   $ 96        
Gross Additions   1,230        
Net Change in Unrealized Appreciation (Depreciation)   $ (1,230)        
Investment, Identifier [Axis]: Arcole Holding Corporation            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ArcoleHoldingCorporationMember      
Investment, Identifier [Axis]: Arcole Holding Corporation, Equity            
Schedule of investments in and advances to affiliated and controlled persons            
Investment type     Equity (excluding STRS JV)      
Dividends, interest and PIK included in income     $ 84      
Beginning Fair Value     6,380      
Gross Reductions     (6,605)      
Net Realized Gain (Loss)     (339)      
Net Change in Unrealized Appreciation (Depreciation)     564      
Ending Fair Value       6,380    
Investment, Identifier [Axis]: Arcserve Cayman GP LLC (d/b/a Arcserve (USA), LLC) Common Units            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanGpLlcMember        
Investment type   whfcl:CommonUnitsMember        
Investment, Identifier [Axis]: Arcserve Cayman GP LLC (d/b/a Arcserve (USA), LLC) Common Units One            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanGpLlcMember        
Investment type   whfcl:CommonUnitsMember        
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 677        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanOpcoLpMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Dividends, interest and PIK included in income   $ 116        
Gross Additions   677        
Net Change in Unrealized Appreciation (Depreciation)   570        
Ending Fair Value   1,247        
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) Unsecured Loan One            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 569        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanOpcoLpMember        
Investment type   whfcl:UnsecuredLoanMember        
Dividends, interest and PIK included in income   $ 54        
Gross Additions   569        
Net Change in Unrealized Appreciation (Depreciation)   12        
Ending Fair Value   581        
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) Unsecured Loan Two            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 583        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanOpcoLpMember        
Investment type   whfcl:UnsecuredLoanMember        
Dividends, interest and PIK included in income   $ 55        
Gross Additions   583        
Net Change in Unrealized Appreciation (Depreciation)   11        
Ending Fair Value   594        
Investment, Identifier [Axis]: Arcserve Cayman Topco LP (d/b/a Arcserve (USA), LLC) Common Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 19,568        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanTopcoLpMember        
Investment type   whfcl:CommonUnitsMember        
Ending Fair Value   $ 9,131        
Investment, Identifier [Axis]: Arcserve Cayman Topco LP (d/b/a Arcserve (USA), LLC) Common Units Two            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArcserveCaymanTopcoLpMember        
Investment type   whfcl:CommonUnitsMember        
Gross Additions   $ 19,568        
Net Change in Unrealized Appreciation (Depreciation)   (10,437)        
Ending Fair Value   9,131        
Investment, Identifier [Axis]: Arcstor Midco, LLC (d/b/a Arcserve (USA), LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 19,568      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ArcstorMidcoLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   10,477        
Ending Fair Value     $ 10,477      
Investment, Identifier [Axis]: Arcstor Midco, LLC (d/b/a Arcserve (USA), LLC Priority First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 1,050      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ArcstorMidcoLLCMember      
Investment type     whfcl:PriorityFirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 1,046        
Ending Fair Value     $ 1,046      
Investment, Identifier [Axis]: Arteriocyte Medical Systems, Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArteriocyteMedicalSystemsInc.Member whfcl:ArteriocyteMedicalSystemsInc.Member      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value   $ 9        
Investment, Identifier [Axis]: Arteriocyte Medical Systems, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,877 $ 4,901      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ArteriocyteMedicalSystemsInc.Member whfcl:ArteriocyteMedicalSystemsInc.Member      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 4,901        
Ending Fair Value   5,021 $ 4,901      
Investment, Identifier [Axis]: Atlas Purchaser, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 2,675      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:AtlasPurchaserIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   2,269        
Ending Fair Value     $ 2,269      
Investment, Identifier [Axis]: Atlas Purchaser, Inc Second Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 14,699      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:AtlasPurchaserIncMember      
Investment type     whfcl:SecondLienSecuredTermLoanMember      
Beginning Fair Value   9,744        
Ending Fair Value     $ 9,744      
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 545        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Avision Holdings, LLC (d/b/a Avision Sales Group)        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 558        
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 648        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Avision Holdings, LLC (d/b/a Avision Sales Group)        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 652        
Investment, Identifier [Axis]: Avision Holdings, LLC Class A LLC Interests            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 287 $ 287      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group)      
Investment type   whfcl:ClassALLCInterestsMember whfcl:ClassALLCInterestsMember      
Beginning Fair Value   $ 411        
Ending Fair Value   577 $ 411      
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,645 $ 2,606      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 2,613        
Ending Fair Value   2,642 $ 2,613      
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 12,972 $ 12,787      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 12,818        
Ending Fair Value   12,955 $ 12,818      
Investment, Identifier [Axis]: BBQ Buyer, LLC Shares            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,100 $ 1,100      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember      
Investment type   Common Stock Common Stock      
Beginning Fair Value   $ 1,330        
Ending Fair Value   907 $ 1,330      
Investment, Identifier [Axis]: BL Products Parent, LP Class A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 788 $ 788      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BLProductsParentLPMember whfcl:BLProductsParentLPMember      
Investment type   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Beginning Fair Value   $ 1,053        
Ending Fair Value   1,012 $ 1,053      
Investment, Identifier [Axis]: BPII-JL Group Holdings LP Class A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 942 $ 825      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BPII-JLGroupHoldingsLPMember whfcl:BPII-JLGroupHoldingsLPMember      
Investment type   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Beginning Fair Value   $ 983        
Ending Fair Value   1,400 $ 983      
Investment, Identifier [Axis]: BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.) First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 447        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.)        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 461        
Investment, Identifier [Axis]: BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,580        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.)        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 7,691        
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 137      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:BannerIndustriesIncMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   137        
Ending Fair Value     $ 137      
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,472 $ 1,366      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc.) Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc.)      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 1,365        
Ending Fair Value   1,477 $ 1,365      
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 412 $ 191      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc.) Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc.)      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 191        
Ending Fair Value   415 $ 191      
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,974 $ 3,015      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc.) Banner Acquisition Holdings, LLC (d/b/a Banner Industries, Inc.)      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 3,015        
Ending Fair Value   $ 2,981 $ 3,015      
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.)      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value   $ (2)        
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 58        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.)      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value   $ 63        
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,543 $ 3,564      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.)      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 3,564        
Ending Fair Value   $ 3,574 $ 3,564      
Investment, Identifier [Axis]: Basel U.S. Acquisition Co., Inc. First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BaselU.s.AcquisitionCo.Inc.Member        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 7        
Investment, Identifier [Axis]: Basel U.S. Acquisition Co., Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,633        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BaselU.s.AcquisitionCo.Inc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 3,675        
Investment, Identifier [Axis]: Branford Filtration, LLC (d/b/a Clean Solutions Group) First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     Branford Filtration, LLC (d/b/a Clean Solutions Group)      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Identifier [Axis]: Branford Filtration, LLC (d/b/a Clean Solutions Group) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 11,358      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     Branford Filtration, LLC (d/b/a Clean Solutions Group)      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   11,358        
Ending Fair Value     $ 11,358      
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 237        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BridgepointHealthcareLLCMember whfcl:BridgepointHealthcareLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ (1)        
Ending Fair Value   231 $ (1)      
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,457 $ 8,973      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BridgepointHealthcareLLCMember whfcl:BridgepointHealthcareLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 8,967        
Ending Fair Value   8,429 $ 8,967      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,120        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ (3)        
Ending Fair Value   2,183 $ (3)      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 230 $ 176      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 181        
Ending Fair Value   248 $ 181      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,774 $ 5,845      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 5,898        
Ending Fair Value   6,952 $ 5,898      
Investment, Identifier [Axis]: Bulk Midco, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 1,989      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:BulkMidcoLLCMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   1,972        
Ending Fair Value     $ 1,972      
Investment, Identifier [Axis]: Bulk Midco, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 19,237      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:BulkMidcoLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   18,997        
Ending Fair Value     $ 18,997      
Investment, Identifier [Axis]: CX Holdco LLC Common Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,116 $ 1,116      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CXHoldcoLLCMember whfcl:CXHoldcoLLCMember      
Investment type   whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Beginning Fair Value   $ 1,715        
Ending Fair Value   2,232 $ 1,715      
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 10,269        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CamarilloFitnessHoldingsLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Dividends, interest and PIK included in income   $ 36        
Gross Additions   10,270        
Net Change in Unrealized Appreciation (Depreciation)   222        
Ending Fair Value   10,492        
Investment, Identifier [Axis]: Camp Facility Services Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 10,325 $ 11,517      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CampFacilityServicesHoldingsLLCMember whfcl:CampFacilityServicesHoldingsLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 11,496        
Ending Fair Value   9,905 $ 11,496      
Investment, Identifier [Axis]: Camp Facility Services Parent, LLC Preferred Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 840 $ 840      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CampFacilityServicesParentLLCMember whfcl:CampFacilityServicesParentLLCMember      
Investment type   Preferred Units [Member] Preferred Units [Member]      
Beginning Fair Value   $ 1,023        
Ending Fair Value   $ 162 $ 1,023      
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CennoxHoldingsLimitedMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 2        
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 665        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CennoxHoldingsLimitedMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 643        
Investment, Identifier [Axis]: Cennox Holdings Limited, First lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 1,182      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:CennoxHoldingsLimitedMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   1,082        
Ending Fair Value     $ 1,082      
Investment, Identifier [Axis]: Cennox Holdings Limited., First lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 3,863      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:CennoxHoldingsLimitedMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   3,538        
Ending Fair Value     $ 3,538      
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 29        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CennoxInc.Member        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 30        
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Term Loan One            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 649        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CennoxInc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 611        
Investment, Identifier [Axis]: Cennox, Inc, First lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 9,851      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:CennoxInc.Member      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   10,257        
Ending Fair Value     $ 10,257      
Investment, Identifier [Axis]: Cennox, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,319        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CennoxInc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 3,344        
Investment, Identifier [Axis]: Chase Products Co. (f/k/a Starco) Second Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,342 $ 2,962      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ChaseProductsCoMember whfcl:ChaseProductsCoMember      
Investment type   whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember      
Dividends, interest and PIK included in income   $ 380 $ 270      
Beginning Fair Value   2,793        
Gross Additions   380 2,961      
Net Change in Unrealized Appreciation (Depreciation)   169 (168)      
Ending Fair Value   3,342 2,793      
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 630 $ 628      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 496        
Ending Fair Value   555 $ 496      
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,690 $ 7,395      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 6,405        
Ending Fair Value   5,085 $ 6,405      
Investment, Identifier [Axis]: Clark Restaurant Service, LLC, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,919        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ClarkRestaurantServiceLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 4,993        
Investment, Identifier [Axis]: CleanChoice Energy, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 15,802 $ 15,715      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CleanChoiceEnergyIncMember whfcl:CleanChoiceEnergyIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 15,954        
Ending Fair Value   $ 16,032 $ 15,954      
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CoastalTelevisionBroadcastingGroupLLCMember whfcl:CoastalTelevisionBroadcastingGroupLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ (3)        
Ending Fair Value   1 $ (3)      
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,808 $ 7,329      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:CoastalTelevisionBroadcastingGroupLLCMember whfcl:CoastalTelevisionBroadcastingGroupLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 7,246        
Ending Fair Value   7,832 $ 7,246      
Investment, Identifier [Axis]: Drew Foam Companies Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 13,541      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:DrewFoamCompaniesIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   13,313        
Ending Fair Value     $ 13,313      
Investment, Identifier [Axis]: Drew Foam Companies Inc, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 13,445        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:DrewFoamCompaniesIncMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 13,437        
Investment, Identifier [Axis]: E-Phoenix Acquisition Co. Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 8,541      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:E-PhoenixAcquisitionCo.Inc.Member      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   8,562        
Ending Fair Value     $ 8,562      
Investment, Identifier [Axis]: E-Phoenix Acquisition Co. Inc., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,299        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:E-PhoenixAcquisitionCo.Inc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 8,342        
Investment, Identifier [Axis]: Eddy Acquisitions, LLC Preferred Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 167 $ 167      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:EddyAcquisitionsLLCMember whfcl:EddyAcquisitionsLLCMember      
Investment type   Preferred Units [Member] Preferred Units [Member]      
Beginning Fair Value   $ 18        
Ending Fair Value     $ 18      
Investment, Identifier [Axis]: Education Dynamics, LLC Senior Preferred Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 167        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:EducationDynamicsLLCMember        
Investment type   whfcl:SeniorPreferredUnitsMember        
Ending Fair Value   $ 100        
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ (22)        
Ending Fair Value   (51) $ (22)      
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 12,989 $ 12,647      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 12,407        
Ending Fair Value   12,449 $ 12,407      
Investment, Identifier [Axis]: EducationDynamics, LLC Subordinated Unsecured Term Loa            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 167      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:EducationDynamicsLLCMember      
Investment type     whfcl:SubordinatedUnsecuredTermLoanMember      
Beginning Fair Value   167        
Ending Fair Value     $ 167      
Investment, Identifier [Axis]: Empire Office, Inc First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 4,545      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:EmpireOfficeIncMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   4,556        
Ending Fair Value     $ 4,556      
Investment, Identifier [Axis]: Empire Office, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 10,931      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:EmpireOfficeIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   10,947        
Ending Fair Value     $ 10,947      
Investment, Identifier [Axis]: Event Services America, Inc. (d/b/a Contemporary Services Corporation) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,857        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:EventServicesAmericaIncMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 7,070        
Investment, Identifier [Axis]: FGI Acquisition Corp. (d/b/a Flexitallic Group SAS) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 15,765 $ 15,786      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:FgiAcquisitionCorpMember whfcl:FgiAcquisitionCorpMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 16,110        
Ending Fair Value   $ 16,026 $ 16,110      
Investment, Identifier [Axis]: FloWorks International LLC First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:FloworksInternationalLlcMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Investment, Identifier [Axis]: FloWorks International LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,280        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:FloworksInternationalLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 5,281        
Investment, Identifier [Axis]: Foodservices Brand Group, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 357 $ 357      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:FoodservicesBrandGroupLlcMember whfcl:FoodservicesBrandGroupLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 200        
Ending Fair Value   321 $ 200      
Investment, Identifier [Axis]: Foodservices Brand Group, LLC Second Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 4,915      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:FoodservicesBrandGroupLlcMember      
Investment type     whfcl:SecondLienSecuredTermLoanMember      
Beginning Fair Value   1,601        
Ending Fair Value     $ 1,601      
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,000 $ 3,018      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 3,025        
Ending Fair Value   $ 3,023 $ 3,025      
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 1        
Ending Fair Value   5 $ 1      
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,937 $ 8,991      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,014        
Ending Fair Value   9,007 $ 9,014      
Investment, Identifier [Axis]: Future Payment Technologies, LP First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 20,382 $ 21,582      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:FuturePaymentTechnologiesLPMember whfcl:FuturePaymentTechnologiesLPMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 21,480        
Ending Fair Value   $ 20,420 $ 21,480      
Investment, Identifier [Axis]: Geo Logic Systems Ltd First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:GeoLogicSystemsLtdMember whfcl:GeoLogicSystemsLtdMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 5        
Ending Fair Value   2 $ 5      
Investment, Identifier [Axis]: Geo Logic Systems Ltd First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 14,234 $ 14,969      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:GeoLogicSystemsLtdMember whfcl:GeoLogicSystemsLtdMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 14,654        
Ending Fair Value   12,883 $ 14,654      
Investment, Identifier [Axis]: Gulf Winds International Acquisition, LLC (d/b/a Gulf Winds International, Inc.) First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 444        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 7        
Ending Fair Value   447 $ 7      
Investment, Identifier [Axis]: Gulf Winds International Acquisition, LLC (d/b/a Gulf Winds International, Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,811 $ 4,685      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 4,738        
Ending Fair Value   $ 8,857 $ 4,738      
Investment, Identifier [Axis]: H I G Camarillo, LP, Limited Partners Interests            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:HIGCamarilloLpMember        
Investment type   whfcl:LimitedPartnerInterestsMember        
Investment, Identifier [Axis]: HC Salon Holdings, Inc First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:HCSalonHoldingsIncMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 8        
Ending Fair Value     $ 8      
Investment, Identifier [Axis]: HC Salon Holdings, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 11,279      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:HCSalonHoldingsIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   11,404        
Ending Fair Value     $ 11,404      
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,384 $ 2,369      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 2,282        
Ending Fair Value   1,354 $ 2,282      
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 480 $ 589      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 547        
Ending Fair Value   455 $ 547      
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,523 $ 9,448      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,074        
Ending Fair Value   5,395 $ 9,074      
Investment, Identifier [Axis]: Hollander Intermediate LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 4,661      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:HollanderIntermediateLlcMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   4,179        
Ending Fair Value     $ 4,179      
Investment, Identifier [Axis]: Honors Holdings, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 4,631      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     Honors Holdings, LLC      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   4,603        
Ending Fair Value     $ 4,603      
Investment, Identifier [Axis]: Honors Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 9,375      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     Honors Holdings, LLC      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,347        
Ending Fair Value     $ 9,347      
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value   $ 4        
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,286 $ 3,503      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 3,504        
Ending Fair Value   3,307 $ 3,504      
Investment, Identifier [Axis]: ImageOne Industries, LLC Common A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 10 $ 7      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ImageOneIndustriesLLCMember whfcl:ImageOneIndustriesLLCMember      
Investment type   whfcl:CommonUnitsMember whfcl:CommonAUnitsMember      
Beginning Fair Value   $ 9        
Ending Fair Value   12 $ 9      
Investment, Identifier [Axis]: Industrial Specialty Services USA LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 11,626      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:IndustrialSpecialtyServicesUSALLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   11,537        
Ending Fair Value     $ 11,537      
Investment, Identifier [Axis]: JVMC Holdings Corp First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 3,521      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:JVMCHoldingsCorpMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   3,522        
Ending Fair Value     $ 3,522      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,326 $ 2,341      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 2,342        
Ending Fair Value   2,343 $ 2,342      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 513 $ 197      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 193        
Ending Fair Value   522 $ 193      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 11,000 $ 11,073      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 11,080        
Ending Fair Value   $ 11,078 $ 11,080      
Investment, Identifier [Axis]: KORE Wireless Group Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value   $ 9        
Investment, Identifier [Axis]: KORE Wireless Group Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,256 $ 6,294      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 6,295        
Ending Fair Value   $ 6,323 $ 6,295      
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Kelso Industries LLC        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,539        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Kelso Industries LLC        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 3,539        
Investment, Identifier [Axis]: Keras Holdings, LLC Shares            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 496 $ 496      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:KerasHoldingsLLCMember whfcl:KerasHoldingsLLCMember      
Investment type   Common Stock Common Stock      
Beginning Fair Value   $ 683        
Ending Fair Value   779 $ 683      
Investment, Identifier [Axis]: LINC Systems, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:LINCSystemsLLCMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   (1)        
Ending Fair Value     $ (1)      
Investment, Identifier [Axis]: LINC Systems, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 8,454      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:LINCSystemsLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 8,443        
Ending Fair Value     $ 8,443      
Investment, Identifier [Axis]: LINC Systems, LLC, First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LINCSystemsLLCMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 3        
Investment, Identifier [Axis]: LINC Systems, LLC, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,114        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LINCSystemsLLCMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 8,155        
Investment, Identifier [Axis]: LMG Holdings, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 13,203      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:LMGHoldingsIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   13,265        
Ending Fair Value     $ 13,265      
Investment, Identifier [Axis]: LMG Holdings, Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:LMGHoldingsIncMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   4        
Ending Fair Value     $ 4      
Investment, Identifier [Axis]: LSCS Holdings, Inc Second Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,953 $ 4,944      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LSCSHoldingsIncMember whfcl:LSCSHoldingsIncMember      
Investment type   whfcl:SecondLienSecuredTermLoanMember whfcl:SecondLienSecuredTermLoanMember      
Beginning Fair Value   $ 4,901        
Ending Fair Value   5,000 $ 4,901      
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,020 $ 5,089      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LabLogisticsLLCMember whfcl:LabLogisticsLLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 5,090        
Ending Fair Value   5,020 $ 5,090      
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 437        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LabLogisticsLLCMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 437        
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,381 $ 5,442      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LabLogisticsLLCMember whfcl:LabLogisticsLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 5,449        
Ending Fair Value   $ 5,383 $ 5,449      
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 14        
Ending Fair Value   10 $ 14      
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 12,981 $ 10,098      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 10,346        
Ending Fair Value   13,312 $ 10,346      
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan A            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,453 $ 5,492      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember      
Investment type   whfcl:FirstLienSecuredTermLoanAMember whfcl:FirstLienSecuredTermLoanAMember      
Beginning Fair Value   $ 5,457        
Ending Fair Value   5,461 $ 5,457      
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan B            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,592 $ 1,441      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember      
Investment type   whfcl:FirstLienSecuredTermLoanBMember whfcl:FirstLienSecuredTermLoanBMember      
Beginning Fair Value   $ 1,406        
Ending Fair Value   $ 1,594 $ 1,406      
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   LogicMonitor, Inc.        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,144        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   LogicMonitor, Inc.        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 6,144        
Investment, Identifier [Axis]: Luxury Brand Holdings, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,556 $ 5,233      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:LuxuryBrandHoldingsIncMember whfcl:LuxuryBrandHoldingsIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 5,280        
Ending Fair Value   4,580 $ 5,280      
Investment, Identifier [Axis]: M2S Group Intermediate Holdings, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,119        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:M2sGroupIntermediateHoldingsIncMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 9,453        
Investment, Identifier [Axis]: MBS Highway, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,157 $ 9,204      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MbsHighwayLlcMember whfcl:MbsHighwayLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,089        
Ending Fair Value   9,212 $ 9,089      
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 804 $ 378      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MgtMergerTargetLlcMember whfcl:MgtMergerTargetLlcMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 389        
Ending Fair Value   817 $ 389      
Investment, Identifier [Axis]: MGT Merger Target, LLC First lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 236        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MgtMergerTargetLlcMember whfcl:MgtMergerTargetLlcMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 11        
Ending Fair Value   249 $ 11      
Investment, Identifier [Axis]: MGT Merger Target, LLC First lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,040 $ 6,084      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MgtMergerTargetLlcMember whfcl:MgtMergerTargetLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 6,194        
Ending Fair Value   7,176 $ 6,194      
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 815      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MSIInformationServicesIncMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   776        
Ending Fair Value     $ 776      
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 7,248      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MSIInformationServicesIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   6,972        
Ending Fair Value     $ 6,972      
Investment, Identifier [Axis]: MSI Information Services, Inc. First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,043        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MSIInformationServicesIncMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 945        
Investment, Identifier [Axis]: MSI Information Services, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,552        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MSIInformationServicesIncMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 7,871        
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   M&M OpCo. LLC (d/b/a Escalent, Inc.) M&M OpCo. LLC (d/b/a Escalent, Inc.)      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ (1)        
Ending Fair Value   5 $ (1)      
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,823 $ 4,602      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   M&M OpCo. LLC (d/b/a Escalent, Inc.) M&M OpCo. LLC (d/b/a Escalent, Inc.)      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 4,580        
Ending Fair Value   4,922 $ 4,580      
Investment, Identifier [Axis]: Manchester Acquisition Sub LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 7,587      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ManchesterAcquisitionSubLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 7,215        
Ending Fair Value     $ 7,215      
Investment, Identifier [Axis]: Marlin DTC-LS Midco 2, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MarlinDTC-LSMidco2LLCMember whfcl:MarlinDTC-LSMidco2LLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ (3)        
Ending Fair Value   (38) $ (3)      
Investment, Identifier [Axis]: Marlin DTC-LS Midco 2, LLC First Lien Secured Term            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 18,798      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MarlinDTC-LSMidco2LLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   18,762        
Ending Fair Value     $ 18,762      
Investment, Identifier [Axis]: Marlin DTC-LS Midco 2, LLC, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 18,577        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MarlinDTC-LSMidco2LLCMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 17,865        
Investment, Identifier [Axis]: Max Solutions Inc. Common Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 400 $ 400      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember      
Investment type   Common Stock Common Stock      
Beginning Fair Value   $ 179        
Ending Fair Value     $ 179      
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MaxSolutionsIncMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   (17)        
Ending Fair Value     $ (17)      
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MaxSolutionsIncMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 6,485      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MaxSolutionsIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   6,488        
Ending Fair Value     $ 6,488      
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 411        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxSolutionsIncMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 402        
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxSolutionsIncMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ (3)        
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,439        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxSolutionsIncMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 6,324        
Investment, Identifier [Axis]: Maxor Acquisition, Inc. (d/b/a Maxor National Pharmacy Services, LLC) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 938        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxorAcquisitionInc.Member        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 938        
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxorAcquisitionInc.Member whfcl:MaxorAcquisitionInc.Member      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 9        
Ending Fair Value   9 $ 9      
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,898 $ 4,922      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MaxorAcquisitionInc.Member whfcl:MaxorAcquisitionInc.Member      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 5,013        
Ending Fair Value   $ 4,986 $ 5,013      
Investment, Identifier [Axis]: Medical Device Inc First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MedicalDeviceIncMember whfcl:MedicalDeviceIncMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 3        
Ending Fair Value   6 $ 3      
Investment, Identifier [Axis]: Medical Device Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,584 $ 2,599      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MedicalDeviceIncMember whfcl:MedicalDeviceIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 2,626        
Ending Fair Value   2,660 $ 2,626      
Investment, Identifier [Axis]: Merriman Holdings LP (d/b/a Escalent, Inc.) Class A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 333 $ 333      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MerrimanHoldingsLPMember whfcl:MerrimanHoldingsLPMember      
Investment type   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Beginning Fair Value   $ 295        
Ending Fair Value   368 $ 295      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 871      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MetaBuyerLLCMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   883        
Ending Fair Value     $ 883      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 1,141      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MetaBuyerLLCMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   1,161        
Ending Fair Value     $ 1,161      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan One            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 13,552      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MetaBuyerLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   13,401        
Ending Fair Value     $ 13,401      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan Two            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 959      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:MetaBuyerLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   971        
Ending Fair Value     $ 971      
Investment, Identifier [Axis]: Meta Buyer LLC., First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 865        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MetaBuyerLLCMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 874        
Investment, Identifier [Axis]: Meta Buyer LLC., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 13,449        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MetaBuyerLLCMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 12,465        
Investment, Identifier [Axis]: Meta Buyer LLC., First Lien Secured Term Loan One            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 952        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MetaBuyerLLCMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 962        
Investment, Identifier [Axis]: Meta Buyer LLC.,First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,145        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MetaBuyerLLCMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 1,160        
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Bridge Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 1,420      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC)      
Investment type     whfcl:FirstLienSecuredBridgeLoanMember      
Beginning Fair Value   1,420        
Ending Fair Value     $ 1,420      
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 632        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC)      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value   $ 642        
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 319        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC)      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value   $ 328        
Investment, Identifier [Axis]: Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,255 $ 9,254      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC) Midwest Texas Tea CA, LLC (d/b/a US Petroleum Partners, LLC)      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,254        
Ending Fair Value   9,399 $ 9,254      
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,572        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MonarchCollectiveHoldingsLlcMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 1,582        
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,119        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MonarchCollectiveHoldingsLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 9,223        
Investment, Identifier [Axis]: Motivational CIV, LLC Class B Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,250 $ 1,250      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MotivationalCIVLLCMember whfcl:MotivationalCIVLLCMember      
Investment type   whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember      
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,175 $ 468      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 338        
Ending Fair Value   1,061 $ 338      
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 10,449 $ 9,888      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 8,790        
Ending Fair Value   9,438 $ 8,790      
Investment, Identifier [Axis]: NNA Services, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,087 $ 9,354      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:NNAServicesLLCMember whfcl:NNAServicesLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,293        
Ending Fair Value   8,941 $ 9,293      
Investment, Identifier [Axis]: NPAV Lessor Corp., First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 719 $ 716      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:NPAVLessorCorp.Member whfcl:NPAVLessorCorp.Member      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 647        
Ending Fair Value   660 $ 647      
Investment, Identifier [Axis]: NPAV Lessor Corp., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,448 $ 7,418      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:NPAVLessorCorp.Member whfcl:NPAVLessorCorp.Member      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 6,706        
Ending Fair Value   5,918 $ 6,706      
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 301 $ 271      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:NavigaIncMember whfcl:NavigaIncMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 268        
Ending Fair Value   169 $ 268      
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,140 $ 3,148      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:NavigaIncMember whfcl:NavigaIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 3,113        
Ending Fair Value   $ 1,763 $ 3,113      
Investment, Identifier [Axis]: New American Crafts Holdings, LLC Class A Units            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:NewAmericanCraftsHoldingsLlcMember whfcl:NewAmericanCraftsHoldingsLlcClassaUnitsMember      
Investment type   whfcl:ClassAUnitsMember whfcl:ClassAUnitsMember      
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 27        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   PANOS Brands, LLC        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 33        
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan, One 05/14/29            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 30        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   PANOS Brands, LLC        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 36        
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,441        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   PANOS Brands, LLC        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 4,505        
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan, One 05/14/29            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,997        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   PANOS Brands, LLC        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 4,054        
Investment, Identifier [Axis]: PFB Holdco, Inc Class A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 423      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PfbHoldingCompanyLlcMember      
Investment type     whfcl:ClassAUnitsMember      
Beginning Fair Value   1,053        
Ending Fair Value     $ 1,053      
Investment, Identifier [Axis]: PFB Holding Company, LLC Class A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 24        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PFBHoldcoIncMember        
Investment type   whfcl:ClassAUnitsMember        
Investment, Identifier [Axis]: PG Dental New Jersey Parent, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 698      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PGDentalNewJerseyParentLLCMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 704        
Ending Fair Value     $ 704      
Investment, Identifier [Axis]: PG Dental New Jersey Parent, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 6,348      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PGDentalNewJerseyParentLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   6,400        
Ending Fair Value     $ 6,400      
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 867        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PltfrmCompaniesLlcMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 916        
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,757        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PltfrmCompaniesLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 8,188        
Investment, Identifier [Axis]: Patagonia Holdco LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 12,602 $ 12,357      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PatagoniaHoldcoLLCMember whfcl:PatagoniaHoldcoLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 13,191        
Ending Fair Value   13,135 $ 13,191      
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 558 $ 560      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PavementPartnersIntercoLLCMember whfcl:PavementPartnersIntercoLLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 569        
Ending Fair Value   569 $ 569      
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 331        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PavementPartnersIntercoLLCMember whfcl:PavementPartnersIntercoLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 5        
Ending Fair Value   341 $ 5      
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,015 $ 4,344      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PavementPartnersIntercoLLCMember whfcl:PavementPartnersIntercoLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 4,405        
Ending Fair Value   5,111 $ 4,405      
Investment, Identifier [Axis]: Pennsylvania Machine Works, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 6,498      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PennsylvaniaMachineWorksLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 6,561        
Ending Fair Value     $ 6,561      
Investment, Identifier [Axis]: Pirtek Holdco, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value   $ 17        
Investment, Identifier [Axis]: Pirtek Holdco, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,298 $ 7,337      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 7,337        
Ending Fair Value   7,425 $ 7,337      
Investment, Identifier [Axis]: PlayMonster LLC First Lien Secured Term Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PlaymonsterGroupLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Dividends, interest and PIK included in income     $ 85      
Beginning Fair Value   1,363 2,977      
Net Change in Unrealized Appreciation (Depreciation)     (1,614)      
Ending Fair Value     1,363 2,977    
Investment, Identifier [Axis]: Playmonster Group Equity, Inc Common Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 460 $ 460      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember      
Investment type   Common Stock Common Stock      
Investment, Identifier [Axis]: Playmonster Group Equity, Inc. Preferred Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,600 $ 3,600      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember      
Investment type   us-gaap:PreferredStockMember us-gaap:PreferredStockMember      
Investment, Identifier [Axis]: Playmonster Group LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,661 $ 3,661      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PlaymonsterGroupLLCMember whfcl:PlayMonsterLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 1,363        
Net Change in Unrealized Appreciation (Depreciation)   272        
Ending Fair Value   1,635 $ 1,363      
Investment, Identifier [Axis]: Playmonster Group LLC, Priority First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,275 $ 1,118      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PlaymonsterGroupLLCMember whfcl:PlayMonsterLLCMember      
Investment type   whfcl:PriorityFirstLienSecuredTermLoanMember whfcl:PriorityFirstLienSecuredTermLoanMember      
Dividends, interest and PIK included in income   $ 157 $ 129      
Beginning Fair Value   1,015 176      
Gross Additions   157 943      
Net Change in Unrealized Appreciation (Depreciation)     (104)      
Ending Fair Value   1,172 1,015 176    
Investment, Identifier [Axis]: Potpourri Group, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 13,767      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PotpourriGroupIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   13,799        
Ending Fair Value     $ 13,799      
Investment, Identifier [Axis]: Poultry Holdings LLC., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 6,904      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:PoultryHoldingsLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   6,904        
Ending Fair Value     $ 6,904      
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,329 $ 1,336      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PowerServiceGroupCrAcquisitionIncMember whfcl:PowerServiceGroupCrAcquisitionIncMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 1,353        
Ending Fair Value   1,354 $ 1,353      
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,642 $ 8,712      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PowerServiceGroupCrAcquisitionIncMember whfcl:PowerServiceGroupCrAcquisitionIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 8,782        
Ending Fair Value   $ 8,784 $ 8,782      
Investment, Identifier [Axis]: Pressurized Holdings, LLC Common Units            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Pressurized Holdings, LLC [Member] Pressurized Holdings, LLC [Member]      
Investment type   whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Investment, Identifier [Axis]: Pressurized Holdings, LLC Preferred Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,537 $ 4,537      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Pressurized Holdings, LLC [Member] Pressurized Holdings, LLC [Member]      
Investment type   Preferred Units [Member] Preferred Units [Member]      
Beginning Fair Value   $ 251        
Gross Additions     $ 4,537      
Net Change in Unrealized Appreciation (Depreciation)   1,406 (4,286)      
Ending Fair Value   $ 1,657 251      
Investment, Identifier [Axis]: Principal Lighting Group, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PrincipalLightingGroupLlcMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Investment, Identifier [Axis]: Principal Lighting Group, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,479        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:PrincipalLightingGroupLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 3,479        
Investment, Identifier [Axis]: Project Castle, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 5,536      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:ProjectCastleIncMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   5,364        
Ending Fair Value     $ 5,364      
Investment, Identifier [Axis]: Quest Events LLC, First Lien Secured Term Loan, 09/30/26            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 11,563        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:QuestEventsLLCMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 11,592        
Investment, Identifier [Axis]: Quest Events, LLC Common Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 376 $ 360      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:QuestEventsLLCMember whfcl:QuestEventsLLCMember      
Investment type   whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Beginning Fair Value   $ 305        
Ending Fair Value   149 $ 305      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 246 $ 246      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:QuestEventsLLCMember whfcl:QuestEventsLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 242        
Ending Fair Value   248 $ 242      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 472 $ 11,663      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:QuestEventsLLCMember whfcl:QuestEventsLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 11,557        
Ending Fair Value   473 $ 11,557      
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,922 $ 2,945      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember      
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   $ 2,965        
Ending Fair Value   2,946 $ 2,965      
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 10,839 $ 10,925      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 10,993        
Ending Fair Value   $ 10,923 $ 10,993      
Investment, Identifier [Axis]: RCKC Acquisitions LLC, First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 106      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 114        
Ending Fair Value   11 $ 114      
Investment, Identifier [Axis]: RLJ Pro-Vac, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,566        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:RLJPro-VacInc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 6,637        
Investment, Identifier [Axis]: Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.) First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.)        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 9        
Investment, Identifier [Axis]: Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,600        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.)        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 8,692        
Investment, Identifier [Axis]: Ross-Simons Topco, LP Preferred Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 514 $ 514      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:Ross-SimonsTopcoLPMember whfcl:Ross-SimonsTopcoLPMember      
Investment type   Preferred Units [Member] Preferred Units [Member]      
Beginning Fair Value   $ 832        
Ending Fair Value   756 $ 832      
Investment, Identifier [Axis]: SFS Global Holding Company Warrants            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SFSGlobalHoldingCompanyMember      
Investment type     Warrant      
Investment, Identifier [Axis]: Salon Republic Holdings, LLC (d/b/a Salon Republic, LLC) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,641        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SalonRepublicHoldingsLlcMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 1,672        
Investment, Identifier [Axis]: Salon Republic Holdings, LLC (d/b/a Salon Republic, LLC) First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SalonRepublicHoldingsLlcMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 13        
Investment, Identifier [Axis]: Salon Republic Holdings, LLC (d/b/a Salon Republic, LLC) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 4,988        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SalonRepublicHoldingsLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 5,063        
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 729      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SalonRepublicHoldingsLlcMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   745        
Ending Fair Value     $ 745      
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 245      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SalonRepublicHoldingsLlcMember      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   258        
Ending Fair Value     $ 258      
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 5,001      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SalonRepublicHoldingsLlcMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   5,077        
Ending Fair Value     $ 5,077      
Investment, Identifier [Axis]: Salon Republic Investments LLC Common Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 400      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SalonRepublicInvestmentsLlcMember      
Investment type     Common Stock      
Beginning Fair Value   241        
Ending Fair Value     $ 241      
Investment, Identifier [Axis]: Salon Republic Investments LLC Preferred Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 200      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SalonRepublicInvestmentsLlcMember      
Investment type     us-gaap:PreferredStockMember      
Beginning Fair Value   218        
Ending Fair Value     $ 218      
Investment, Identifier [Axis]: Salon Republic Investments LLC, Common Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 400        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SalonRepublicInvestmentsLlcMember        
Investment type   Common Stock        
Ending Fair Value   $ 132        
Investment, Identifier [Axis]: Salon Republic Investments LLC, Preferred Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 200        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SalonRepublicInvestmentsLlcMember        
Investment type   us-gaap:PreferredStockMember        
Ending Fair Value   $ 242        
Investment, Identifier [Axis]: Sigue Corporation Warrants            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 2,890      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SigueCorporationMember      
Investment type     Warrant      
Beginning Fair Value   $ 3,472        
Ending Fair Value     $ 3,472      
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 3        
Ending Fair Value   5 $ 3      
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 22,401 $ 20,385      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 20,407        
Ending Fair Value   22,441 $ 20,407      
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,682        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SmaltoInc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 6,654        
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan Interest Rate 10.18            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 6,821      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SmaltoInc.Member      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   7,172        
Ending Fair Value     $ 7,172      
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan Interest Rate 11.50            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 987      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SmaltoInc.Member      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   996        
Ending Fair Value     $ 996      
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan One            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 967        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SmaltoInc.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 978        
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Class A Common Stock            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,941 $ 1,941      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember      
Investment type   us-gaap:CommonClassAMember us-gaap:CommonClassAMember      
Beginning Fair Value   $ 130        
Ending Fair Value   173 $ 130      
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc First Lien Secured Term Loan C            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,819 $ 1,654      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember      
Investment type   whfcl:FirstLienSecuredTermLoanCMember whfcl:FirstLienSecuredTermLoanCMember      
Beginning Fair Value   $ 1,623        
Ending Fair Value   1,790 $ 1,623      
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Warrants            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 793 $ 793      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember      
Investment type   Warrant Warrant      
Beginning Fair Value   $ 53        
Ending Fair Value   70 $ 53      
Investment, Identifier [Axis]: Solar Holdings Bidco Limited First Lien Secured Term Loan CDOR            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 2,759      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SolarHoldingsBidcoLimitedMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   2,892        
Ending Fair Value     $ 2,892      
Investment, Identifier [Axis]: Solar Holdings Bidco Limited First Lien Secured Term Loan SOFR            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 2,744      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SolarHoldingsBidcoLimitedMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   2,786        
Ending Fair Value     $ 2,786      
Investment, Identifier [Axis]: Solar Holdings Bidco Limited First Lien Secured Term Loan SONIA            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 205      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SolarHoldingsBidcoLimitedMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   217        
Ending Fair Value     $ 217      
Investment, Identifier [Axis]: Solar Holdings Bidco Limited, First Lien Secured Delayed Draw Loan CDOR            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 324      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SolarHoldingsBidcoLimitedMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   342        
Ending Fair Value     $ 342      
Investment, Identifier [Axis]: Solar Holdings Bidco Limited, First Lien Secured Delayed Draw Loan SOFR            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 360      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SolarHoldingsBidcoLimitedMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   366        
Ending Fair Value     $ 366      
Investment, Identifier [Axis]: Solar Holdings Bidco Limited, First Lien Secured Delayed Draw Loan SONIA            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 882      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SolarHoldingsBidcoLimitedMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   984        
Ending Fair Value     $ 984      
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 4,039      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SourceCodeHoldingsLLCMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   4,047        
Ending Fair Value     $ 4,047      
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 14,772      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SourceCodeHoldingsLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   14,806        
Ending Fair Value     $ 14,806      
Investment, Identifier [Axis]: Source Code Holdings, LLC., First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 3,839        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SourceCodeHoldingsLLCMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 3,854        
Investment, Identifier [Axis]: Source Code Holdings, LLC., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 14,041        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SourceCodeHoldingsLLCMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 14,095        
Investment, Identifier [Axis]: Sterling Pure Blocker, LLC (d/b/a Banner Industries, Inc.) Class B Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 404 $ 404      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:SterlingPureBlockerLlcMember whfcl:SterlingPureBlockerLlcMember      
Investment type   whfcl:ClassBUnitsMember whfcl:ClassBUnitsMember      
Beginning Fair Value   $ 404        
Ending Fair Value   388 $ 404      
Investment, Identifier [Axis]: StoicLane MidCo, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 5,466      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:StoiclaneMidcoLlcMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   5,633        
Ending Fair Value     $ 5,633      
Investment, Identifier [Axis]: StoicLane MidCo, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 4,518      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:StoiclaneMidcoLlcMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   4,606        
Ending Fair Value     $ 4,606      
Investment, Identifier [Axis]: Sunless, Inc. First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 485      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SunlessInc.Member      
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   484        
Ending Fair Value     $ 484      
Investment, Identifier [Axis]: Sunless, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 5,459      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:SunlessInc.Member      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   5,473        
Ending Fair Value     $ 5,473      
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 573        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 577        
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 574        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 576        
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,629        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 5,643        
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   TOT Group, Inc. (d/b/a Netevia Group LLC)        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ (1)        
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   TOT Group, Inc. (d/b/a Netevia Group LLC)        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,074        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   TOT Group, Inc. (d/b/a Netevia Group LLC)        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 8,067        
Investment, Identifier [Axis]: TOUR Intermediate Holdings, LLC First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 2,315      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:TOURIntermediateHoldingsLLCMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   2,320        
Ending Fair Value     $ 2,320      
Investment, Identifier [Axis]: TOUR Intermediate Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 2,643      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:TOURIntermediateHoldingsLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   2,657        
Ending Fair Value     $ 2,657      
Investment, Identifier [Axis]: TableTrust Brands LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,468        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TabletrustBrandsLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 2,468        
Investment, Identifier [Axis]: Team Car Care Holdings, First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 12,391      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:TeamCarCareHoldingsLLCMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   12,407        
Ending Fair Value     $ 12,407      
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 1,051 $ 1,228      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Telestream Holdings Corporation Telestream Holdings Corporation      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 1,223        
Ending Fair Value   1,009 $ 1,223      
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 17,496 $ 15,580      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Telestream Holdings Corporation Telestream Holdings Corporation      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 15,522        
Ending Fair Value   17,063 $ 15,522      
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 795        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ (31)        
Ending Fair Value   761 $ (31)      
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 11,309 $ 11,282      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 10,904        
Ending Fair Value   10,895 $ 10,904      
Investment, Identifier [Axis]: Token Buyer, Inc First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,709 $ 6,695      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TokenBuyerIncMember whfcl:TokenBuyerIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 5,966        
Ending Fair Value   $ 5,658 $ 5,966      
Investment, Identifier [Axis]: Trailhead Media LLC First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Trailhead Media LLC        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Investment, Identifier [Axis]: Trailhead Media LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Trailhead Media LLC        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Investment, Identifier [Axis]: Trailhead Media LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 6,548        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   Trailhead Media LLC        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 6,548        
Investment, Identifier [Axis]: Transervice Holdings, Inc. (d/b/a Transervice Logistics, Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 8,481 $ 8,648      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TranserviceHoldingsIncMember whfcl:TranserviceHoldingsIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 8,743        
Ending Fair Value   8,715 $ 8,743      
Investment, Identifier [Axis]: Trimlite Buyer LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 15,006 $ 15,472      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TrimliteBuyerLLCMember whfcl:TrimliteBuyerLLCMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 14,810        
Ending Fair Value   $ 13,206 $ 14,810      
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TriplepointAcquisitionHoldingsLlcMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 9        
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TriplepointAcquisitionHoldingsLlcMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 12        
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,254        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TriplepointAcquisitionHoldingsLlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 5,338        
Investment, Identifier [Axis]: Turnberry Solutions., First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TurnberrySolutionsInc.Member whfcl:TurnberrySolutionsInc.Member      
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value   $ 2        
Ending Fair Value   4 $ 2      
Investment, Identifier [Axis]: Turnberry Solutions., First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 5,924 $ 5,962      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TurnberrySolutionsInc.Member whfcl:TurnberrySolutionsInc.Member      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 5,979        
Ending Fair Value   5,964 $ 5,979      
Investment, Identifier [Axis]: Twin Ridge CRS, LP (d/b/a CRS OneSource) Class A Common Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 317        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:TwinRidgeCrsLpMember        
Investment type   whfcl:ClassCommonUnitsMember        
Ending Fair Value   $ 350        
Investment, Identifier [Axis]: US Methanol Midco LLC (d/b/a US Methanol LLC) First Lien Secured Delayed Draw Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 9,345      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:UsMethanolMidcoLlcMember      
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value   9,449        
Ending Fair Value     $ 9,449      
Investment, Identifier [Axis]: US Methanol Midco LLC (d/b/a US Methanol LLC) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment     $ 5,111      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name     whfcl:UsMethanolMidcoLlcMember      
Investment type     First Lien Secured Term Loan [Member]      
Beginning Fair Value   5,153        
Ending Fair Value     $ 5,153      
Investment, Identifier [Axis]: UserZoom Technologies, Inc. First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 9,618 $ 9,570      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:UserzoomTechnologiesIncMember whfcl:UserzoomTechnologiesIncMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 9,719        
Ending Fair Value   9,809 $ 9,719      
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Series A Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 314 $ 314      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:VistriaBlockedMgtInvestorLpMember whfcl:VistriaBlockedMgtInvestorLpMember      
Investment type   whfcl:SeriesUnitsMember whfcl:ClassAUnitsMember      
Beginning Fair Value   $ 406        
Ending Fair Value   $ 493 $ 406      
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation)        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 9        
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 12,124        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation)        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 12,216        
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Equity            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember      
Investment type   Equity (excluding STRS JV) Equity (excluding STRS JV)      
Dividends, interest and PIK included in income   $ 6,861 $ 6,158      
Beginning Fair Value   22,782 20,160      
Gross Additions     1,104      
Net Change in Unrealized Appreciation (Depreciation)   (41) 1,518      
Ending Fair Value   22,741 22,782 20,160    
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Interests            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 21,104 $ 21,104      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WHFSTRSOhioSeniorLoanFundMember whfcl:WHFSTRSOhioSeniorLoanFundMember      
Investment type   whfcl:LLCInterestsMember whfcl:LLCInterestsMember      
Beginning Fair Value   $ 22,782        
Ending Fair Value   22,741 $ 22,782      
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Subordinated Note            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 84,416 $ 84,416      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember      
Investment type   Subordinated Notes Subordinated Notes      
Dividends, interest and PIK included in income   $ 9,838 $ 9,488      
Beginning Fair Value   84,416 80,000      
Gross Additions     4,416      
Ending Fair Value   $ 84,416 84,416 80,000    
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Delayed Draw Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember        
Investment type   whfcl:FirstLienSecuredDelayedDrawLoanMember        
Ending Fair Value   $ 2        
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Revolving Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 253        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 254        
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 7,548        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 7,555        
Investment, Identifier [Axis]: What If Media Group, LLC Common Units            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 851 $ 851      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WhatIfMediaGroupLLCMember whfcl:WhatIfMediaGroupLLCMember      
Investment type   whfcl:CommonUnitsMember whfcl:CommonUnitsMember      
Beginning Fair Value   $ 1,615        
Ending Fair Value   1,756 $ 1,615      
Investment, Identifier [Axis]: Whitestone Home Furnishings, LLC (d/b/a Saatva, Inc.) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 2,887 $ 2,919      
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:WhitestoneHomeFurnishingsLlcMember whfcl:WhitestoneHomeFurnishingsLlcMember      
Investment type   First Lien Secured Term Loan [Member] First Lien Secured Term Loan [Member]      
Beginning Fair Value   $ 2,919        
Ending Fair Value   $ 2,930 $ 2,919      
Investment, Identifier [Axis]: Zephyr Buyer, L.P. (d/b/a The Weather Company, LLC) First Lien Secured Revolving Loan            
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ZephyrBuyerL.p.Member        
Investment type   whfcl:FirstLienSecuredRevolvingLoanMember        
Ending Fair Value   $ 48        
Investment, Identifier [Axis]: Zephyr Buyer, L.P. (d/b/a The Weather Company, LLC) First Lien Secured Term Loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment   $ 13,789        
Schedule of investments in and advances to affiliated and controlled persons            
Issuer name   whfcl:ZephyrBuyerL.p.Member        
Investment type   First Lien Secured Term Loan [Member]        
Ending Fair Value   $ 14,166        
Sklar Holdings, Inc [Member] | First Lien Secured Term Loan [Member]            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment           $ 3,339
Paydown received under investments $ 690          
Pressurized Holdings, LLC [Member] | Preferred Units [Member]            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment $ 3,892          
Honors Holdings, LLC | First lien secured term loan, delayed draw loan and revolver loan            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment         $ 17,816  
Honors Holdings, LLC | First lien secured investments            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment         7,582  
Camarillo Fitness Holdings, LLC And H.I.G. Camarillo, L.P. | First lien secured term loan and common equity interests            
Investments in and Advances to Affiliates [Line Items]            
Cost of investment         $ 10,234  
Non-controlled affiliate company investments            
Schedule of investments in and advances to affiliated and controlled persons            
Dividends, interest and PIK included in income   798 398      
Beginning Fair Value   5,422 9,533      
Gross Additions   32,204 8,441      
Gross Reductions     (6,605)      
Net Realized Gain (Loss)     (339)      
Net Change in Unrealized Appreciation (Depreciation)   (7,775) (5,608) (5,239)    
Ending Fair Value   29,851 5,422 9,533    
Controlled affiliate company investments            
Schedule of investments in and advances to affiliated and controlled persons            
Dividends, interest and PIK included in income   17,079 16,993      
Beginning Fair Value   112,948 100,160      
Gross Additions   3,795 21,278      
Net Change in Unrealized Appreciation (Depreciation)   (9,213) (8,490) (447)    
Ending Fair Value   $ 107,530 $ 112,948 $ 100,160