v3.26.1
INVESTMENTS - Affiliated and Controlled Persons (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Oct. 31, 2025
Sep. 30, 2025
Sep. 30, 2024
Investments in and Advances to Affiliates [Line Items]                
Weighted average remaining term of debt investments     3 years   3 years 3 months 18 days      
Cost basis of non-accrual loans $ 29,960   $ 29,960   $ 19,665      
Fair value of non-accrual loans 15,096   15,096   10,561      
Cost of investment 594,296   594,296   607,574      
Schedule of investments in and advances to affiliated and controlled persons                
Beginning Fair Value     578,649          
Net Change in Unrealized Appreciation (Depreciation)     3,832 $ 15,524        
Ending Fair Value 569,202   569,202   578,649      
Equity Investments                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment 75,885   75,885   75,288      
Schedule of investments in and advances to affiliated and controlled persons                
Beginning Fair Value     58,535          
Ending Fair Value 62,923   62,923   58,535      
Debt Investments                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment 518,411   518,411   532,286      
Schedule of investments in and advances to affiliated and controlled persons                
Beginning Fair Value     520,114          
Ending Fair Value 506,279   506,279   520,114      
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 554   $ 554   $ 405      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:AbCentersAcquisitionCorporationMember   whfcl:AbCentersAcquisitionCorporationMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 409          
Ending Fair Value $ 564   $ 564   $ 409      
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   whfcl:AbCentersAcquisitionCorporationMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 5          
Ending Fair Value $ 8   8   $ 5      
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 12,870   $ 12,870   $ 12,922      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:AbCentersAcquisitionCorporationMember   whfcl:AbCentersAcquisitionCorporationMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 12,973          
Ending Fair Value $ 12,976   12,976   $ 12,973      
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 $ 20,269   $ 20,269   $ 20,227      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 20,026          
Ending Fair Value $ 20,409   20,409   $ 20,026      
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      
Beginning Fair Value     $ 15          
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   whfcl:ApgLionsPurchaserLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 6          
Ending Fair Value $ 5   5   $ 6      
Investment, Identifier [Axis]: APG Lions Purchaser, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,970   $ 3,970   $ 4,002      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ApgLionsPurchaserLlcMember   whfcl:ApgLionsPurchaserLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,046          
Ending Fair Value $ 4,008   4,008   $ 4,046      
Investment, Identifier [Axis]: American Crafts Holdings, LLC, Warrants                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:AmericanCraftsHoldingsLlcMember      
Investment type         Warrant      
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      
Investment type         whfcl:SuperPriorityFirstLienSecuredTermLoanMember      
Net Realized Gain (Loss)         $ (2,094)      
Net Change in Unrealized Appreciation (Depreciation)         $ 2,094      
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:AmericanCraftsLCMember      
Investment type         whfcl:FirstLienSecuredDelayedDrawLoanMember      
Net Realized Gain (Loss)         $ (1,458)      
Net Change in Unrealized Appreciation (Depreciation)         $ 1,458      
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Term Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:AmericanCraftsLCMember      
Investment type         First Lien Secured Term Loan [Member]      
Net Realized Gain (Loss)         $ (8,720)      
Net Change in Unrealized Appreciation (Depreciation)         $ 8,720      
Investment, Identifier [Axis]: American Crafts, LC Priority First Lien Secured Term Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:AmericanCraftsLCMember      
Investment type         whfcl:PriorityFirstLienSecuredLoanMember      
Net Realized Gain (Loss)         $ (5,105)      
Net Change in Unrealized Appreciation (Depreciation)         $ 5,105      
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:AmericanCraftsLCMember      
Investment type         whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember      
Beginning Fair Value       373 $ 373      
Net Realized Gain (Loss)         (2,373)      
Net Change in Unrealized Appreciation (Depreciation)         $ 2,000      
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:SuperSeniorPriorityFirstLienSecuredTermLoanOneMember      
Net Realized Gain (Loss)         $ (1,230)      
Net Change in Unrealized Appreciation (Depreciation)         1,230      
Investment, Identifier [Axis]: Apollon Holdings, LLC (d/b/a Apollon Wealth Management, LLC) First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,787   $ 4,787   $ 2,339      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ApollonHoldingsLlcMember   whfcl:ApollonHoldingsLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 2,442          
Ending Fair Value $ 4,936   4,936   $ 2,442      
Investment, Identifier [Axis]: Apollon Holdings, LLC (d/b/a Apollon Wealth Management, LLC) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,516   $ 6,516   $ 6,542      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ApollonHoldingsLlcMember   whfcl:ApollonHoldingsLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,632          
Ending Fair Value $ 6,645   $ 6,645   $ 6,632      
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   whfcl:ArcserveCaymanGpLlcMember      
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember   whfcl:CommonUnitsMember      
Investment, Identifier [Axis]: Arcserve Cayman Opco LP (d/b/a Arcserve (USA), LLC) First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 825   $ 825   $ 775      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ArcserveCaymanOpcoLpMember   whfcl:ArcserveCaymanOpcoLpMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Dividends, interest and PIK included in income     $ 62   $ 120      
Beginning Fair Value     1,240 1,247 1,247      
Gross Additions     52   98      
Net Change in Unrealized Appreciation (Depreciation)     (66)   (105)      
Ending Fair Value $ 1,226   1,226   1,240      
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 $ 658   $ 658   $ 627      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ArcserveCaymanOpcoLpMember   whfcl:ArcserveCaymanOpcoLpMember      
Investment type whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember      
Dividends, interest and PIK included in income     $ 31   $ 58      
Beginning Fair Value     636 581 581      
Gross Additions     30   58      
Net Change in Unrealized Appreciation (Depreciation)     (1)   (3)      
Ending Fair Value $ 665   665   636      
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 $ 673   $ 673   $ 642      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ArcserveCaymanOpcoLpMember   whfcl:ArcserveCaymanOpcoLpMember      
Investment type whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember      
Dividends, interest and PIK included in income     $ 31   $ 59      
Beginning Fair Value     650 594 594      
Gross Additions     31   58      
Net Change in Unrealized Appreciation (Depreciation)     (1)   (2)      
Ending Fair Value $ 680   680   650      
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   $ 19,568   $ 19,568      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ArcserveCaymanTopcoLpMember   whfcl:ArcserveCaymanTopcoLpMember      
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember   whfcl:CommonUnitsMember      
Beginning Fair Value     $ 9,144 9,131 $ 9,131      
Net Change in Unrealized Appreciation (Depreciation)     5   13      
Ending Fair Value $ 9,149   9,149   9,144      
Investment, Identifier [Axis]: Atlas Parent, LLC, Common Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,682   $ 1,682   $ 1,682      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:AtlasParentLlcMember   whfcl:AtlasParentLlcMember      
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember   whfcl:CommonUnitsMember      
Beginning Fair Value     $ 1,853          
Ending Fair Value $ 1,690   1,690   $ 1,853      
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 $ 543   $ 543   $ 544      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:AvisionHoldingsLLCMember   whfcl:AvisionHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 546          
Ending Fair Value $ 544   544   $ 546      
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 $ 646   $ 646   $ 647      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:AvisionHoldingsLLCMember   whfcl:AvisionHoldingsLLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 650          
Ending Fair Value $ 647   647   $ 650      
Investment, Identifier [Axis]: Avision Holdings, LLC (d/b/a Avision Sales Group), Class A LLC Interests                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 319   $ 319   $ 299      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:AvisionHoldingsLLCMember   whfcl:AvisionHoldingsLLCMember      
Investment type whfcl:ClassALLCInterestsMember   whfcl:ClassALLCInterestsMember   whfcl:ClassALLCInterestsMember      
Beginning Fair Value     $ 322          
Ending Fair Value $ 297   297   $ 322      
Investment, Identifier [Axis]: BBQ Buyer, LLC Shares                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,100   $ 1,100   $ 1,100      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BBQBuyerLLCMember   whfcl:BBQBuyerLLCMember      
Investment type whfcl:SharesMember   whfcl:SharesMember   Common Stock      
Beginning Fair Value     $ 1,003          
Ending Fair Value $ 911   911   $ 1,003      
Investment, Identifier [Axis]: BL Products Parent, LP (d/b/a Bishop Lifting Products, Inc.) Class A Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 788   $ 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   whfcl:ClassAUnitsMember      
Beginning Fair Value     $ 561          
Ending Fair Value $ 344   344   $ 561      
Investment, Identifier [Axis]: BPII-JL Group Holdings LP (d/b/a Juniper Landscaping Holdings LLC) Class A Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 942   $ 942   $ 942      
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   whfcl:ClassAUnitsMember      
Beginning Fair Value     $ 1,645          
Ending Fair Value $ 1,577   1,577   $ 1,645      
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 $ 271   $ 271   $ 270      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.)   BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 283          
Ending Fair Value $ 283   283   $ 283      
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 $ 6,998   $ 6,998   $ 7,231      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.)   BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 7,331          
Ending Fair Value $ 7,092   7,092   $ 7,331      
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,825   $ 1,825   $ 1,845      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BannerAcquisitionHoldingsLLCMember   whfcl:BannerAcquisitionHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 1,766          
Ending Fair Value $ 1,848   1,848   $ 1,766      
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 166   $ 166   $ 166      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BannerAcquisitionHoldingsLLCMember   whfcl:BannerAcquisitionHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 118          
Ending Fair Value $ 180   180   $ 118      
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,881   $ 2,881   $ 2,912      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BannerAcquisitionHoldingsLLCMember   whfcl:BannerAcquisitionHoldingsLLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 2,787          
Ending Fair Value $ 2,917   2,917   $ 2,787      
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 442   $ 442   $ 367      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BarrettPurchaserLlcMember   whfcl:BarrettPurchaserLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 366          
Ending Fair Value $ 439   439   $ 366      
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,512   $ 3,512   $ 3,523      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BarrettPurchaserLlcMember   whfcl:BarrettPurchaserLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 3,493          
Ending Fair Value $ 3,480   3,480   $ 3,493      
Investment, Identifier [Axis]: Buckeye Acquiror LLC (d/b/a Superior Environmental Solutions, LLC) First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:BuckeyeAcquirorLlcMember      
Investment type         whfcl:FirstLienSecuredDelayedDrawLoanMember      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,371   $ 2,371   $ 2,281      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BuckeyeAcquirorLlcMember   whfcl:BuckeyeAcquirorLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 2,323          
Ending Fair Value $ 2,406   2,406   $ 2,323      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 635   $ 635   $ 365      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:BuckeyeAcquirorLlcMember   whfcl:BuckeyeAcquirorLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 379          
Ending Fair Value $ 648   648   $ 379      
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,713   $ 6,713   $ 6,733      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,834          
Ending Fair Value $ 6,795   6,795   $ 6,834      
Investment, Identifier [Axis]: CX Holdco LLC Common Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,116   $ 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   whfcl:CommonUnitsMember      
Beginning Fair Value     $ 218          
Ending Fair Value         $ 218      
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,216   $ 1,216   $ 1,135      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Camarillo Fitness Holdings, LLC [Member]   Camarillo Fitness Holdings, LLC [Member]      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 196          
Gross Additions     81   $ 1,135      
Net Change in Unrealized Appreciation (Depreciation)     (28)   (939)      
Ending Fair Value $ 249   249   196      
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,231   $ 10,231   $ 10,231      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Camarillo Fitness Holdings, LLC [Member]   Camarillo Fitness Holdings, LLC [Member]      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Dividends, interest and PIK included in income         $ (38)      
Beginning Fair Value     $ 5,354 10,492 10,492      
Gross Reductions         (39)      
Net Change in Unrealized Appreciation (Depreciation)     (2,791)   (5,099)      
Ending Fair Value $ 2,563   2,563   5,354      
Investment, Identifier [Axis]: Camp Facility Services Holdings, LLC (d/b/a Camp Construction Services, Inc.) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,147   $ 10,147   $ 10,230      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,781          
Ending Fair Value $ 9,380   9,380   $ 9,781      
Investment, Identifier [Axis]: Camp Facility Services Parent, LLC Preferred Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 840   $ 840   $ 840      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CampFacilityServicesParentLLCMember   whfcl:CampFacilityServicesParentLLCMember      
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember      
Beginning Fair Value     $ 31          
Ending Fair Value         $ 31      
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 217   $ 217   $ 206      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CennoxHoldingsLimitedMember   whfcl:CennoxHoldingsLimitedMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 205          
Ending Fair Value $ 206   206   $ 205      
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 712   $ 712   $ 721      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CennoxHoldingsLimitedMember   whfcl:CennoxHoldingsLimitedMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 717          
Ending Fair Value $ 673   673   $ 717      
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 142   $ 142   $ 133      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CennoxInc.Member   whfcl:CennoxInc.Member      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 129          
Ending Fair Value $ 132   132   $ 129      
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 678   $ 678   $ 676      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CennoxInc.Member   whfcl:CennoxInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 694          
Ending Fair Value $ 663   663   $ 694      
Investment, Identifier [Axis]: Cennox, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,485   $ 3,485   $ 3,485      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CennoxInc.Member   whfcl:CennoxInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 3,369          
Ending Fair Value $ 3,259   3,259   $ 3,369      
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 $ 3,404   $ 3,404   $ 3,404      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ChaseProductsCoMember   whfcl:ChaseProductsCoMember      
Investment type whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember      
Dividends, interest and PIK included in income     $ 157   $ 385      
Beginning Fair Value     3,404 3,342 3,342      
Gross Additions         157      
Gross Reductions         (95)      
Ending Fair Value $ 3,404   3,404   3,404      
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 632   $ 632   $ 561      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ClaridgeProductsandEquipmentLLCMember   whfcl:ClaridgeProductsandEquipmentLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 498          
Ending Fair Value $ 618   618   $ 498      
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,245   $ 5,245   $ 5,123      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,661          
Ending Fair Value $ 5,142   5,142   $ 4,661      
Investment, Identifier [Axis]: Clark Restaurant Service, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 215   $ 215   $ 4,889      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ClarkRestaurantServiceLlcMember   whfcl:ClarkRestaurantServiceLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,928          
Ending Fair Value $ 218   218   $ 4,928      
Investment, Identifier [Axis]: Clark Restaurant Service, LLC First Lien Secured Term Loan, One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,839   $ 4,839          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ClarkRestaurantServiceLlcMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 4,877   $ 4,877          
Investment, Identifier [Axis]: Colonnade Parent, Inc. (d/b/a Naviga Inc.) First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 279   $ 279   $ 287      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ColonnadeParentIncMember   whfcl:ColonnadeParentIncMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 158          
Ending Fair Value $ 159   159   $ 158      
Investment, Identifier [Axis]: Colonnade Parent, Inc. (d/b/a Naviga Inc.) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,883   $ 2,883   $ 2,988      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ColonnadeParentIncMember   whfcl:ColonnadeParentIncMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 1,925          
Ending Fair Value $ 1,920   1,920   $ 1,925      
Investment, Identifier [Axis]: Cultural Experiences Abroad, LLC (d/b/a Cultural Experiences Abroad, Inc.) First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,030   $ 1,030          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CulturalExperiencesAbroadLlcMember          
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 1,032   $ 1,032          
Investment, Identifier [Axis]: Cultural Experiences Abroad, LLC (d/b/a Cultural Experiences Abroad, Inc.) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 9,353   $ 9,353          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CulturalExperiencesAbroadLlcMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 9,365   $ 9,365          
Investment, Identifier [Axis]: Drew Foam Companies Inc First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 13,270   $ 13,270   $ 13,331      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:DrewFoamCompaniesIncMember   whfcl:DrewFoamCompaniesIncMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 13,314          
Ending Fair Value $ 13,245   $ 13,245   $ 13,314      
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ElmDebtcoLlcMember   whfcl:ElmDebtcoLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value $ 6   $ 6          
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 125   $ 125          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ElmDebtcoLlcMember   whfcl:ElmDebtcoLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value $ 136   $ 136          
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,465   $ 5,465   $ 5,488      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ElmDebtcoLlcMember   whfcl:ElmDebtcoLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,488          
Ending Fair Value $ 5,515   5,515   $ 5,488      
Investment, Identifier [Axis]: Eddy Acquisitions, LLC (d/b/a EducationDynamics, LLC) Preferred Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 167   $ 167   $ 167      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:EddyAcquisitionsLLCMember   whfcl:EddyAcquisitionsLLCMember      
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember      
Investment, Identifier [Axis]: Education Dynamics, LLC Senior Preferred Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 167   $ 167   $ 167      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:EducationDynamicsLLCMember   whfcl:EducationDynamicsLLCMember      
Investment type whfcl:SeniorPreferredUnitsMember   whfcl:SeniorPreferredUnitsMember   whfcl:SeniorPreferredUnitsMember      
Ending Fair Value $ 61   $ 61          
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 538   $ 538   $ 358      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:EducationDynamicsLLCMember   whfcl:EducationDynamicsLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 320          
Ending Fair Value $ 542   542   $ 320      
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 12,522   $ 12,522   $ 12,532      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 12,137          
Ending Fair Value $ 12,564   12,564   $ 12,137      
Investment, Identifier [Axis]: Empire amp; Co Inc. (d/b/a Empire Office, Inc.), First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,123   $ 10,123          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:EmpireOfficeIncMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 10,120   $ 10,120          
Investment, Identifier [Axis]: FloWorks International LLC, First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 659   $ 659   $ 661      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:FloworksInternationalLlcMember   whfcl:FloworksInternationalLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 663          
Ending Fair Value $ 665   665   $ 663      
Investment, Identifier [Axis]: FloWorks International LLC, First Lien Secured Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,226   $ 5,226   $ 5,248      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:FloworksInternationalLlcMember   whfcl:FloworksInternationalLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,262          
Ending Fair Value $ 5,267   5,267   $ 5,262      
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,972   $ 2,972   $ 2,981      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ForwardSolutionsLlcMember   whfcl:ForwardSolutionsLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 2,993          
Ending Fair Value $ 2,977   2,977   $ 2,993      
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 173   $ 173   $ 617      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ForwardSolutionsLlcMember   whfcl:ForwardSolutionsLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 619          
Ending Fair Value $ 174   174   $ 619      
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 8,852   $ 8,852   $ 8,880      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,914          
Ending Fair Value $ 8,868   8,868   $ 8,914      
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 493   $ 493   $ 248      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Four Winds Health, LLC   Four Winds Health, LLC      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 272          
Ending Fair Value $ 527   $ 527   $ 272      
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Four Winds Health, LLC   Four Winds Health, LLC      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 8          
Ending Fair Value $ 10   10   $ 8      
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,275   $ 4,275   $ 4,286      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Four Winds Health, LLC   Four Winds Health, LLC      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,343          
Ending Fair Value $ 4,360   4,360   $ 4,343      
Investment, Identifier [Axis]: Future Payment Technologies, LP First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 18,545   $ 18,545   $ 19,160      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 19,175          
Ending Fair Value $ 18,552   $ 18,552   $ 19,175      
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:G2LatherAcquisitionCorp.Member   whfcl:G2LatherAcquisitionCorp.Member      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 10          
Ending Fair Value $ 24   $ 24   $ 10      
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:G2LatherAcquisitionCorp.Member   whfcl:G2LatherAcquisitionCorp.Member      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 4          
Ending Fair Value $ 7   7   $ 4      
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,836   $ 3,836   $ 3,850      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:G2LatherAcquisitionCorp.Member   whfcl:G2LatherAcquisitionCorp.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 3,873          
Ending Fair Value $ 3,886   3,886   $ 3,873      
Investment, Identifier [Axis]: GTT Communications Global, LLC (d/b/a GTT Communications, Inc.), First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 14,964   $ 14,964   $ 15,014      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:GttCommunicationsGlobalLlcMember   whfcl:GttCommunicationsGlobalLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 15,129          
Ending Fair Value $ 15,157   15,157   $ 15,129      
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 $ 697   $ 697   $ 596      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:GulfWindsInternationalAcquisitionLlcMember   whfcl:GulfWindsInternationalAcquisitionLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 584          
Ending Fair Value $ 684   684   $ 584      
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 $ 8,843   $ 8,843   $ 8,820      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,697          
Ending Fair Value $ 8,704   $ 8,704   $ 8,697      
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   whfcl:HIGCamarilloLpMember      
Investment type whfcl:LimitedPartnerInterestsMember   whfcl:LimitedPartnerInterestsMember   whfcl:LimitedPartnerInterestsMember      
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 1,150      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:HRGManagementLLCMember      
Investment type         whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 1,154          
Ending Fair Value         $ 1,154      
Investment, Identifier [Axis]: HRG Management, 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:HRGManagementLLCMember      
Investment type         whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     701          
Ending Fair Value         $ 701      
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 4,588      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:HRGManagementLLCMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     4,602          
Ending Fair Value         $ 4,602      
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      
Investment type         whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     2          
Ending Fair Value         $ 2      
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 3,262      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:ITSBuyerIncMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     3,271          
Ending Fair Value         $ 3,271      
Investment, Identifier [Axis]: ImageOne Industries, LLC Common A Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 18   $ 18   $ 13      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ImageOneIndustriesLLCMember   whfcl:ImageOneIndustriesLLCMember      
Investment type whfcl:CommonAUnitsMember   whfcl:CommonAUnitsMember   whfcl:CommonAUnitsMember      
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 311   $ 311          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ImpactAdvisorsLlcMember   whfcl:ImpactAdvisorsLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 10          
Ending Fair Value $ 322   322   $ 10      
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 278   $ 278          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ImpactAdvisorsLlcMember   whfcl:ImpactAdvisorsLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 4          
Ending Fair Value $ 281   281   $ 4      
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,115   $ 4,115   $ 4,132      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ImpactAdvisorsLlcMember   whfcl:ImpactAdvisorsLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,169          
Ending Fair Value $ 4,148   4,148   $ 4,169      
Investment, Identifier [Axis]: Industrial Service Solutions WC, Inc, First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 191   $ 191          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:IndustrialServiceSolutionsMember          
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 192   $ 192          
Investment, Identifier [Axis]: Industrial Service Solutions WC, Inc, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,062   $ 5,062          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:IndustrialServiceSolutionsMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 5,072   $ 5,072          
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)   Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 2          
Ending Fair Value         $ 2      
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Revolving Loan One                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)   Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 1          
Ending Fair Value         $ 1      
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,890   $ 2,890   $ 2,899      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)   Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 2,907          
Ending Fair Value $ 2,891   2,891   $ 2,907      
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,477   $ 2,477   $ 2,484      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)   Infotree Holdco LLC (d/b/a Infotree Global Solutions LLC)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 2,492          
Ending Fair Value $ 2,478   2,478   $ 2,492      
Investment, Identifier [Axis]: Intermedia Cloud Communications, Inc. (d/b/a Intermedia.net, Inc.),First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,601   $ 6,601          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:IntermediaCloudCommunicationsIncMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 6,600   $ 6,600          
Investment, Identifier [Axis]: Intermedia Cloud Communications, Inc. (d/b/a  Intermedia.net, Inc.), First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:IntermediaCloudCommunicationsIncMember          
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember          
Investment, Identifier [Axis]: Island Energy Services, LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,056   $ 10,056          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:IslandEnergyServicesLlcMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 10,266   $ 10,266          
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,984   $ 1,984   $ 884      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:JuniperLandscapingHoldingsLLCMember   whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 910          
Ending Fair Value $ 2,008   2,008   $ 910      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,299   $ 2,299   $ 2,309      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:JuniperLandscapingHoldingsLLCMember   whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 2,319          
Ending Fair Value $ 2,307   2,307   $ 2,319      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 399   $ 399   $ 235      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:JuniperLandscapingHoldingsLLCMember   whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 246          
Ending Fair Value $ 407   407   $ 246      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 523   $ 523   $ 309      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:JuniperLandscapingHoldingsLLCMember   whfcl:JuniperLandscapingHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 314          
Ending Fair Value $ 527   527   $ 314      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 448   $ 448   $ 449      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 454          
Ending Fair Value $ 452   452   $ 454      
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,872   $ 10,872   $ 10,917      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 10,964          
Ending Fair Value $ 10,907   $ 10,907   $ 10,964      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 10          
Ending Fair Value $ 8   8   $ 10      
Investment, Identifier [Axis]: KORE Wireless Group Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,199   $ 6,199   $ 6,218      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,290          
Ending Fair Value $ 6,258   6,258   $ 6,290      
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,057   $ 5,057   $ 4,710      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Kelso Industries LLC   Kelso Industries LLC      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,823          
Ending Fair Value $ 5,127   $ 5,127   $ 4,823      
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   whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 13   $ 13          
Investment, Identifier [Axis]: Keras Holdings, LLC Shares                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 496   $ 496   $ 496      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:KerasHoldingsLLCMember   whfcl:KerasHoldingsLLCMember      
Investment type whfcl:SharesMember   whfcl:SharesMember   Common Stock      
Beginning Fair Value     $ 446          
Ending Fair Value $ 50   50   $ 446      
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      
Investment, Identifier [Axis]: LINC Systems, LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 7,895      
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     $ 7,900          
Ending Fair Value         $ 7,900      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 4          
Ending Fair Value $ 3   3   $ 4      
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 13,456   $ 13,456   $ 13,486      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 13,584          
Ending Fair Value $ 13,519   13,519   $ 13,584      
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan A                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,001   $ 5,001   $ 5,119      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:LiftBrandsIncMember   whfcl:LiftBrandsIncMember      
Investment type whfcl:FirstLienSecuredTermLoanAMember   whfcl:FirstLienSecuredTermLoanAMember   whfcl:FirstLienSecuredTermLoanAMember      
Beginning Fair Value     $ 5,120          
Ending Fair Value $ 5,001   5,001   $ 5,120      
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan B                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,779   $ 1,779   $ 1,752      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:LiftBrandsIncMember   whfcl:LiftBrandsIncMember      
Investment type whfcl:FirstLienSecuredTermLoanBMember   whfcl:FirstLienSecuredTermLoanBMember   whfcl:FirstLienSecuredTermLoanBMember      
Beginning Fair Value     $ 1,753          
Ending Fair Value $ 1,779   1,779   $ 1,753      
Investment, Identifier [Axis]: LogicMonitor, Inc. - First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 8,138   $ 8,138   $ 8,130      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     LogicMonitor, Inc.   LogicMonitor, Inc.      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,186          
Ending Fair Value $ 8,220   $ 8,220   $ 8,186      
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     LogicMonitor, Inc.   LogicMonitor, Inc.      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value $ 5   $ 5          
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.   LogicMonitor, Inc.      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 5          
Ending Fair Value $ 7   7   $ 5      
Investment, Identifier [Axis]: M2S Group Intermediate Holdings, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 8,503   $ 8,503   $ 8,838      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:M2sGroupIntermediateHoldingsIncMember   whfcl:M2sGroupIntermediateHoldingsIncMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,276          
Ending Fair Value $ 8,892   8,892   $ 9,276      
Investment, Identifier [Axis]: MBS Highway, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 9,097   $ 9,097   $ 9,122      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,184          
Ending Fair Value $ 9,128   9,128   $ 9,184      
Investment, Identifier [Axis]: MGT Merger Target, LLC (d/b/a MGT Consulting Group), First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 486   $ 486   $ 281      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     MGT Merger Target, LLC [Member]   MGT Merger Target, LLC [Member]      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 300          
Ending Fair Value $ 479   479   $ 300      
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,297   $ 1,297          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     MGT Merger Target, LLC [Member]          
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 1,302   $ 1,302          
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Delayed Draw Loan, One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 1,300      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         MGT Merger Target, LLC [Member]      
Investment type         whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     1,322          
Ending Fair Value         $ 1,322      
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 670   $ 670   $ 705      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     MGT Merger Target, LLC [Member]   MGT Merger Target, LLC [Member]      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 715          
Ending Fair Value $ 670   670   $ 715      
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 8,406   $ 8,406   $ 8,430      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     MGT Merger Target, LLC [Member]   MGT Merger Target, LLC [Member]      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,567          
Ending Fair Value $ 8,428   8,428   $ 8,567      
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 75   $ 75          
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 4          
Ending Fair Value $ 78   78   $ 4      
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 $ 4,686   $ 4,686   $ 4,748      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,827          
Ending Fair Value $ 4,751   $ 4,751   $ 4,827      
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MarkiMicrowaveLlcMember   whfcl:MarkiMicrowaveLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value $ 6   $ 6          
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MarkiMicrowaveLlcMember   whfcl:MarkiMicrowaveLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value $ 6   $ 6          
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,976   $ 5,976   $ 5,986      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MarkiMicrowaveLlcMember   whfcl:MarkiMicrowaveLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,985          
Ending Fair Value $ 5,995   $ 5,995   $ 5,985      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ (39)          
Ending Fair Value $ (25)   (25)   $ (39)      
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 $ 17,643   $ 17,643   $ 18,019      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MarlinDTC-LSMidco2LLCMember   whfcl:MarlinDTC-LSMidco2LLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 17,299          
Ending Fair Value $ 17,002   17,002   $ 17,299      
Investment, Identifier [Axis]: Max Solutions Inc. Common Stock                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 400   $ 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   Common Stock      
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 406   $ 406   $ 407      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MaxSolutionsIncMember   whfcl:MaxSolutionsIncMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 408          
Ending Fair Value $ 408   $ 408   $ 408      
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   whfcl:MaxSolutionsIncMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 1          
Ending Fair Value $ 1   1   $ 1      
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,368   $ 6,368   $ 6,392      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MaxSolutionsIncMember   whfcl:MaxSolutionsIncMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,420          
Ending Fair Value $ 6,416   6,416   $ 6,420      
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 $ 927   $ 927   $ 930      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MaxorAcquisitionInc.Member   whfcl:MaxorAcquisitionInc.Member      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 942          
Ending Fair Value $ 933   933   $ 942      
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,860   $ 4,860   $ 4,872      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,974          
Ending Fair Value $ 4,925   $ 4,925   $ 4,974      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 8          
Ending Fair Value $ 6   6   $ 8      
Investment, Identifier [Axis]: Media Source, LLC (d/b/a Media Source Inc.) First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 147   $ 147          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Media Source, LLC (d/b/a Media Source Inc.)   Media Source, LLC (d/b/a Media Source Inc.)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Dividends, interest and PIK included in income     $ 5   $ 4      
Beginning Fair Value     17          
Gross Additions     148   218      
Gross Reductions         (218)      
Net Change in Unrealized Appreciation (Depreciation)     (16)   17      
Ending Fair Value $ 149   149   17      
Investment, Identifier [Axis]: Media Source, LLC (d/b/a Media Source Inc.) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,323   $ 4,323   $ 4,242      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Media Source, LLC (d/b/a Media Source Inc.)   Media Source, LLC (d/b/a Media Source Inc.)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Dividends, interest and PIK included in income     $ 204   $ 139      
Beginning Fair Value     4,242          
Gross Additions     102   4,252      
Gross Reductions     (21)   (11)      
Net Change in Unrealized Appreciation (Depreciation)     (64)   1      
Ending Fair Value $ 4,259   4,259   4,242      
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   $ 333      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MerrimanHoldingsLPMember   whfcl:MerrimanHoldingsLPMember      
Investment type whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember      
Beginning Fair Value     $ 312          
Ending Fair Value $ 286   286   $ 312      
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan Two                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 6,653      
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     6,653          
Ending Fair Value         $ 6,653      
Investment, Identifier [Axis]: Meta Buyer LLC, First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,597   $ 1,597          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MetaBuyerLLCMember   whfcl:MetaBuyerLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value $ 1,599   $ 1,599          
Investment, Identifier [Axis]: Meta Buyer LLC, First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 337   $ 337          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MetaBuyerLLCMember   whfcl:MetaBuyerLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value $ 342   $ 342          
Investment, Identifier [Axis]: Meta Buyer LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,625   $ 6,625          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MetaBuyerLLCMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 6,647   $ 6,647          
Investment, Identifier [Axis]: Meta Buyer LLC, First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,391   $ 5,391   $ 5,378      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MetaBuyerLLCMember   whfcl:MetaBuyerLLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,374          
Ending Fair Value $ 5,234   5,234   $ 5,374      
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 $ 634   $ 634   $ 629      
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   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 639          
Ending Fair Value $ 644   644   $ 639      
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 $ 495   $ 495   $ 563      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 572          
Ending Fair Value $ 502   502   $ 572      
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 $ 9,119   $ 9,119   $ 9,051      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,193          
Ending Fair Value $ 9,262   9,262   $ 9,193      
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 1,562      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:MonarchCollectiveHoldingsLlcMember      
Investment type         whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     1,553          
Ending Fair Value         $ 1,553      
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 9,073      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:MonarchCollectiveHoldingsLlcMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     9,061          
Ending Fair Value         $ 9,061      
Investment, Identifier [Axis]: Motivational CIV, LLC Class B Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,250   $ 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   whfcl:ClassBUnitsMember      
Beginning Fair Value     $ 774          
Ending Fair Value $ 951   951   $ 774      
Investment, Identifier [Axis]: Motivational Marketing, LLC (d/b/a Motivational Fulfillment), LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 940   $ 940   $ 626      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:MotivationalMarketingLLCMember   whfcl:MotivationalMarketingLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 637          
Ending Fair Value $ 949   949   $ 637      
Investment, Identifier [Axis]: Motivational Marketing, LLC (d/b/a Motivational Fulfillment), LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 13,052   $ 13,052   $ 13,104      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 13,135          
Ending Fair Value $ 13,109   $ 13,109   $ 13,135      
Investment, Identifier [Axis]: NM Z Holdco Inc First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:NmZHoldcoInc.Member          
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 6   $ 6          
Investment, Identifier [Axis]: NM Z Holdco Inc. (d/b/a Zep, Inc.) First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     NM Z Holdco Inc. (d/b/a Zep, Inc.)   NM Z Holdco Inc. (d/b/a Zep, Inc.)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 6          
Ending Fair Value $ 7   7   $ 6      
Investment, Identifier [Axis]: NM Z Holdco Inc. (d/b/a Zep, Inc.) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,250   $ 10,250   $ 10,293      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     NM Z Holdco Inc. (d/b/a Zep, Inc.)   NM Z Holdco Inc. (d/b/a Zep, Inc.)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 10,378          
Ending Fair Value $ 10,412   10,412   $ 10,378      
Investment, Identifier [Axis]: NNA Services, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 7,922   $ 7,922   $ 8,060      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,037          
Ending Fair Value $ 7,903   7,903   $ 8,037      
Investment, Identifier [Axis]: NPAV Lessor Corp. First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 723   $ 723   $ 722      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 660          
Ending Fair Value $ 678   678   $ 660      
Investment, Identifier [Axis]: NPAV Lessor Corp. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,302   $ 5,302   $ 5,493      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,022          
Ending Fair Value $ 4,969   4,969   $ 5,022      
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      
Investment type         whfcl:ClassAUnitsMember      
Investment, Identifier [Axis]: Oil amp; Gas Storage amp; Transportation First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 10,077      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:IslandEnergyServicesLlcMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     10,158          
Ending Fair Value         $ 10,158      
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 60   $ 60          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     PANOS Brands, LLC   PANOS Brands, LLC      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 6          
Ending Fair Value $ 66   66   $ 6      
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 54   $ 54          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     PANOS Brands, LLC   PANOS Brands, LLC      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 6          
Ending Fair Value $ 59   59   $ 6      
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,918   $ 3,918          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     PANOS Brands, LLC          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 3,963   $ 3,963          
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,526   $ 3,526   $ 4,414      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     PANOS Brands, LLC   PANOS Brands, LLC      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,475          
Ending Fair Value $ 3,567   3,567   $ 4,475      
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         $ 3,973      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         PANOS Brands, LLC      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     4,027          
Ending Fair Value         $ 4,027      
Investment, Identifier [Axis]: PFB Holding Company, LLC Class A Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 24   $ 24   $ 24      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PfbHoldingCompanyLlcMember   whfcl:PFBHoldcoIncMember      
Investment type whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember      
Investment, Identifier [Axis]: PGI Parent LLC (d/b/a Prime Electric, Inc.), First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:PgiParentLlcMember      
Investment type         whfcl:FirstLienSecuredRevolvingLoanMember      
Investment, Identifier [Axis]: PGI Parent LLC (d/b/a Prime Electric, Inc.), First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 5,026      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:PgiParentLlcMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,026          
Ending Fair Value         $ 5,026      
Investment, Identifier [Axis]: PGI Parent LLC, First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 372   $ 372          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PgiParentLlcMember          
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 376   $ 376          
Investment, Identifier [Axis]: PGI Parent LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,005   $ 5,005          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PgiParentLlcMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 5,027   $ 5,027          
Investment, Identifier [Axis]: Patagonia Holdco LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 12,839      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:PatagoniaHoldcoLLCMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 11,603          
Ending Fair Value         $ 11,603      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 9          
Ending Fair Value $ 10   10   $ 9      
Investment, Identifier [Axis]: Pirtek Holdco, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 12,162   $ 12,162   $ 12,284      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 12,332          
Ending Fair Value $ 12,247   $ 12,247   $ 12,332      
Investment, Identifier [Axis]: Playmonster Group Equity Inc Common Equity                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PlaymonsterGroupEquityIncMember          
Investment type Common Stock   Common Stock          
Investment, Identifier [Axis]: Playmonster Group Equity Inc Preferred Equity                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PlaymonsterGroupEquityIncMember          
Investment type us-gaap:PreferredStockMember   us-gaap:PreferredStockMember          
Investment, Identifier [Axis]: Playmonster Group Equity, Inc Common Stock                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 460   $ 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   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   $ 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   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   $ 3,661      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PlaymonsterGroupLLCMember   whfcl:PlaymonsterGroupLLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 1,729 1,635 $ 1,635      
Net Change in Unrealized Appreciation (Depreciation)     697   94      
Ending Fair Value $ 2,426   2,426   1,729      
Investment, Identifier [Axis]: Playmonster Group LLC, Priority First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,589   $ 1,589   $ 1,438      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PlaymonsterGroupLLCMember   whfcl:PlaymonsterGroupLLCMember      
Investment type whfcl:PriorityFirstLienSecuredTermLoanMember   whfcl:PriorityFirstLienSecuredTermLoanMember   whfcl:PriorityFirstLienSecuredTermLoanMember      
Dividends, interest and PIK included in income     $ 85   $ 164      
Beginning Fair Value     1,355 1,172 1,172      
Gross Additions     262   164      
Gross Reductions     (111)          
Net Change in Unrealized Appreciation (Depreciation)     86   19      
Ending Fair Value $ 1,592   $ 1,592   $ 1,355      
Investment, Identifier [Axis]: Pressurized Holdings, LLC Common Units                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PressurizedHoldingsLlcMember   whfcl:PressurizedHoldingsLlcMember      
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember   whfcl:CommonUnitsMember      
Net Change in Unrealized Appreciation (Depreciation)     $ 1,944          
Ending Fair Value $ 1,944   1,944          
Investment, Identifier [Axis]: Pressurized Holdings, LLC Preferred Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 4,537   $ 4,537   $ 4,537      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PressurizedHoldingsLlcMember   whfcl:PressurizedHoldingsLlcMember      
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember      
Beginning Fair Value     $ 4,784 1,657 $ 1,657      
Net Change in Unrealized Appreciation (Depreciation)     3,510   3,127      
Ending Fair Value $ 8,294   $ 8,294   $ 4,784      
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   whfcl:PrincipalLightingGroupLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 4          
Ending Fair Value $ 5   5   $ 4      
Investment, Identifier [Axis]: Principal Lighting Group, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,242   $ 3,242   $ 3,312      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:PrincipalLightingGroupLlcMember   whfcl:PrincipalLightingGroupLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 3,343          
Ending Fair Value $ 3,278   3,278   $ 3,343      
Investment, Identifier [Axis]: Quest Events, LLC Common Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 402   $ 402   $ 385      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Quest Events, LLC [Member]   Quest Events, LLC [Member]      
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember   whfcl:CommonUnitsMember      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 128   $ 128   $ 122      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Quest Events, LLC [Member]   Quest Events, LLC [Member]      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 113          
Ending Fair Value $ 130   130   $ 113      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 300   $ 300   $ 288      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Quest Events, LLC [Member]   Quest Events, LLC [Member]      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 262          
Ending Fair Value $ 300   300   $ 262      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,272   $ 1,272   $ 1,258      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Quest Events, LLC [Member]   Quest Events, LLC [Member]      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 1,187          
Ending Fair Value $ 1,281   1,281   $ 1,187      
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 11,797   $ 11,797   $ 11,655      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Quest Events, LLC [Member]   Quest Events, LLC [Member]      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 11,041          
Ending Fair Value $ 11,806   11,806   $ 11,041      
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,886   $ 2,886   $ 2,898      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:RCKCAcquisitionsLLCMember   whfcl:RCKCAcquisitionsLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 2,827          
Ending Fair Value $ 2,784   $ 2,784   $ 2,827      
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:RCKCAcquisitionsLLCMember   whfcl:RCKCAcquisitionsLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ (35)          
Ending Fair Value $ (50)   (50)   $ (35)      
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,700   $ 10,700   $ 10,747      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 10,481          
Ending Fair Value $ 10,321   10,321   $ 10,481      
Investment, Identifier [Axis]: RLJ Pro-Vac, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,540   $ 6,540   $ 6,546      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:RLJPro-VacInc.Member   whfcl:RLJPro-VacInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,396          
Ending Fair Value $ 6,409   $ 6,409   $ 6,396      
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:RewardsNetworkInc.Member   whfcl:RewardsNetworkInc.Member      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value $ 20   $ 20          
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 157   $ 157   $ 627      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:RewardsNetworkInc.Member   whfcl:RewardsNetworkInc.Member      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 627          
Ending Fair Value $ 178   178   $ 627      
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,026   $ 10,026   $ 10,036      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:RewardsNetworkInc.Member   whfcl:RewardsNetworkInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 10,034          
Ending Fair Value $ 10,109   $ 10,109   $ 10,034      
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.)   Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 12          
Ending Fair Value $ 8   8   $ 12      
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 $ 8,392   $ 8,392   $ 8,483      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.)   Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,631          
Ending Fair Value $ 8,470   8,470   $ 8,631      
Investment, Identifier [Axis]: Ross-Simons Topco, LP Preferred Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 514   $ 514   $ 514      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:Ross-SimonsTopcoLPMember   whfcl:Ross-SimonsTopcoLPMember      
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember      
Beginning Fair Value     $ 735          
Ending Fair Value $ 625   $ 625   $ 735      
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 293      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ScicBuyerInc.Member   whfcl:ScicBuyerInc.Member      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 319          
Ending Fair Value $ 27   $ 27   $ 319      
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ScicBuyerInc.Member   whfcl:ScicBuyerInc.Member      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 25          
Ending Fair Value $ 23   23   $ 25      
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 8,936   $ 8,936   $ 8,970      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ScicBuyerInc.Member   whfcl:ScicBuyerInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,142          
Ending Fair Value $ 9,135   9,135   $ 9,142      
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 $ 1,634   $ 1,634   $ 1,637      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SalonRepublicHoldingsLlcMember   whfcl:SalonRepublicHoldingsLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 1,653          
Ending Fair Value $ 1,642   $ 1,642   $ 1,653      
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   whfcl:SalonRepublicHoldingsLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 8          
Ending Fair Value $ 7   7   $ 8      
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 $ 4,967   $ 4,967   $ 4,974      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SalonRepublicHoldingsLlcMember   whfcl:SalonRepublicHoldingsLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,021          
Ending Fair Value $ 5,008   5,008   $ 5,021      
Investment, Identifier [Axis]: Salon Republic Investments LLC Common Stock                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 400   $ 400   $ 400      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SalonRepublicInvestmentsLlcMember   whfcl:SalonRepublicInvestmentsLlcMember      
Investment type Common Stock   Common Stock   Common Stock      
Beginning Fair Value     $ 6          
Ending Fair Value         $ 6      
Investment, Identifier [Axis]: Salon Republic Investments LLC Preferred Stock                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 200   $ 200   $ 200      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SalonRepublicInvestmentsLlcMember   whfcl:SalonRepublicInvestmentsLlcMember      
Investment type us-gaap:PreferredStockMember   us-gaap:PreferredStockMember   us-gaap:PreferredStockMember      
Beginning Fair Value     $ 265          
Ending Fair Value $ 235   $ 235   $ 265      
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   whfcl:FirstLienSecuredRevolvingLoanMember      
Ending Fair Value $ 20   $ 20          
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 13,213   $ 13,213   $ 13,259      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 13,255          
Ending Fair Value $ 13,393   13,393   $ 13,255      
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan One                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 938   $ 938   $ 936      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SmaltoInc.Member   whfcl:SmaltoInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 944          
Ending Fair Value $ 944   944   $ 944      
Investment, Identifier [Axis]: Smalto Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,489   $ 6,489   $ 6,480      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SmaltoInc.Member   whfcl:SmaltoInc.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 7,281          
Ending Fair Value $ 7,080   7,080   $ 7,281      
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   $ 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   us-gaap:CommonClassAMember      
Beginning Fair Value     $ 507          
Ending Fair Value $ 434   434   $ 507      
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc First Lien Secured Term Loan C                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,196   $ 2,196   $ 2,095      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SnapFitnessHoldingsIncMember   whfcl:SnapFitnessHoldingsIncMember      
Investment type whfcl:FirstLienSecuredTermLoanCMember   whfcl:FirstLienSecuredTermLoanCMember   whfcl:FirstLienSecuredTermLoanCMember      
Beginning Fair Value     $ 2,098          
Ending Fair Value $ 2,199   2,199   $ 2,098      
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Warrants                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 793   $ 793   $ 793      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SnapFitnessHoldingsIncMember   whfcl:SnapFitnessHoldingsIncMember      
Investment type Warrant   Warrant   Warrant      
Beginning Fair Value     $ 205          
Ending Fair Value $ 176   176   $ 205      
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,771   $ 3,771   $ 3,811      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SourceCodeHoldingsLLCMember   whfcl:SourceCodeHoldingsLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 3,831          
Ending Fair Value $ 3,748   3,748   $ 3,831      
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 13,788   $ 13,788   $ 13,935      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SourceCodeHoldingsLLCMember   whfcl:SourceCodeHoldingsLLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 14,009          
Ending Fair Value $ 13,703   13,703   $ 14,009      
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   $ 404      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:SterlingPureBlockerLlcMember   whfcl:SterlingPureBlockerLlcMember      
Investment type whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember      
Beginning Fair Value     $ 57          
Ending Fair Value $ 247   247   $ 57      
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,792   $ 2,792   $ 987      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)   Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 1,000          
Ending Fair Value $ 2,850   2,850   $ 1,000      
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 722   $ 722   $ 444      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)   Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 450          
Ending Fair Value $ 732   732   $ 450      
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,579   $ 5,579   $ 5,596      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)   Surge Amuze Holdings Inc. (d/b/a Amuze Products II, Inc.)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,645          
Ending Fair Value $ 5,649   5,649   $ 5,645      
Investment, Identifier [Axis]: TOT Group, Inc. (d/b/a Netevia Group LLC) First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,083   $ 1,083   $ 1,084      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     TOT Group, Inc. (d/b/a Netevia Group LLC)   TOT Group, Inc. (d/b/a Netevia Group LLC)      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 1,091          
Ending Fair Value $ 1,103   $ 1,103   $ 1,091      
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)   TOT Group, Inc. (d/b/a Netevia Group LLC)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 1          
Ending Fair Value $ 7   7   $ 1      
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 $ 8,987   $ 8,987   $ 9,000      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     TOT Group, Inc. (d/b/a Netevia Group LLC)   TOT Group, Inc. (d/b/a Netevia Group LLC)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,023          
Ending Fair Value $ 9,109   $ 9,109   $ 9,023      
Investment, Identifier [Axis]: TVG I-EMSI Parent, LLC Class A units                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TvgIEmsiParentLlcMember   whfcl:TvgIEmsiParentLlcMember      
Investment type whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember      
Investment, Identifier [Axis]: TVG I-EMSI Parent, LLC Class B units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,291   $ 3,291   $ 3,291      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TvgIEmsiParentLlcMember   whfcl:TvgIEmsiParentLlcMember      
Investment type whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember      
Beginning Fair Value     $ 3,291          
Gross Additions         $ 3,291      
Net Change in Unrealized Appreciation (Depreciation)     (760)          
Ending Fair Value $ 2,531   2,531   3,291      
Investment, Identifier [Axis]: TableTrust Brands LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,708   $ 2,708   $ 2,453      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TabletrustBrandsLlcMember   whfcl:TabletrustBrandsLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 2,480          
Ending Fair Value $ 2,716   $ 2,716   $ 2,480      
Investment, Identifier [Axis]: Telestream 2 LLC (d/b/a Telestream Holdings Corporation), First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Telestream 2 LLC (d/b/a Telestream Holdings Corporation)   Telestream 2 LLC (d/b/a Telestream Holdings Corporation)      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 20          
Ending Fair Value $ 16   16   $ 20      
Investment, Identifier [Axis]: Telestream 2 LLC (d/b/a Telestream Holdings Corporation), First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 11,379   $ 11,379   $ 11,437      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Telestream 2 LLC (d/b/a Telestream Holdings Corporation)   Telestream 2 LLC (d/b/a Telestream Holdings Corporation)      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 11,437          
Ending Fair Value $ 11,379   11,379   $ 11,437      
Investment, Identifier [Axis]: Telestream Topco 2 LLC (d/b/a Telestream Holdings Corporation), Common Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 7,109   $ 7,109   $ 7,109      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Telestream 2 LLC (d/b/a Telestream Holdings Corporation)   whfcl:TelestreamTopco2LlcMember      
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember   whfcl:CommonUnitsMember      
Beginning Fair Value     $ 8,027          
Ending Fair Value $ 8,095   8,095   $ 8,027      
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 458   $ 458          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TexasExpressWashLlcMember   whfcl:TexasExpressWashLlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Ending Fair Value $ 516   $ 516          
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 101   $ 101   $ 100      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TexasExpressWashLlcMember   whfcl:TexasExpressWashLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 100          
Ending Fair Value $ 110   110   $ 100      
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,759   $ 10,759   $ 10,778      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TexasExpressWashLlcMember   whfcl:TexasExpressWashLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 10,776          
Ending Fair Value $ 11,015   11,015   $ 10,776      
Investment, Identifier [Axis]: Texas Express Wash, LLC Second Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,502   $ 1,502   $ 1,436      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TexasExpressWashLlcMember   whfcl:TexasExpressWashLlcMember      
Investment type whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember      
Beginning Fair Value     $ 1,435          
Ending Fair Value $ 1,573   1,573   $ 1,435      
Investment, Identifier [Axis]: Texas Wash Holdings, LLC (d/b/a ClearWater Express Wash), Warrants                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 197   $ 197   $ 197      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TexasWashHoldingsLlcMember   whfcl:TexasWashHoldingsLlcMember      
Investment type Warrant   Warrant   Warrant      
Beginning Fair Value     $ 197          
Ending Fair Value $ 204   204   $ 197      
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Delayed Draw Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 790   $ 790   $ 793      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CromCorporationMember   whfcl:CromCorporationMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 806          
Ending Fair Value $ 811   811   $ 806      
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 166   $ 166   $ 308      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CromCorporationMember   whfcl:CromCorporationMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 317          
Ending Fair Value $ 174   174   $ 317      
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 3,983   $ 3,983   $ 3,998      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:CromCorporationMember   whfcl:CromCorporationMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 4,049          
Ending Fair Value $ 4,058   4,058   $ 4,049      
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 383   $ 383          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TheKyjenCompanyLLCMember   whfcl:TheKyjenCompanyLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ (132)          
Ending Fair Value $ 78   78   $ (132)      
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 11,307   $ 11,307   $ 11,400      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,790          
Ending Fair Value $ 7,701   7,701   $ 9,790      
Investment, Identifier [Axis]: Token Buyer, Inc First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment         $ 1,363      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name         whfcl:TokenBuyerIncMember      
Investment type         First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 1,199          
Ending Fair Value         $ 1,199      
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     whfcl:TrailheadMediaLLCMember   whfcl:TrailheadMediaLLCMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ (3)          
Ending Fair Value $ (5)   $ (5)   $ (3)      
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TrailheadMediaLLCMember   whfcl:TrailheadMediaLLCMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ (3)          
Ending Fair Value $ (4)   (4)   $ (3)      
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,555   $ 6,555   $ 6,553      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TrailheadMediaLLCMember   whfcl:TrailheadMediaLLCMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,532          
Ending Fair Value $ 6,524   6,524   $ 6,532      
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 $ 7,498   $ 7,498   $ 7,586      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 7,701          
Ending Fair Value $ 7,583   7,583   $ 7,701      
Investment, Identifier [Axis]: Trimlite Buyer LLC (d/b/a Trimlite LLC) First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 1,382   $ 1,382   $ 14,957      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 13,748          
Ending Fair Value $ 1,329   $ 1,329   $ 13,748      
Investment, Identifier [Axis]: Trimlite Buyer LLC, First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TrimliteBuyerLLCMember          
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 4   $ 4          
Investment, Identifier [Axis]: Trimlite Buyer LLC, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 2,718   $ 2,718          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TrimliteBuyerLLCMember          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 2,729   $ 2,729          
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   whfcl:TriplepointAcquisitionHoldingsLlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 18          
Ending Fair Value $ 16   16   $ 18      
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 7,951   $ 7,951   $ 7,975      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TriplepointAcquisitionHoldingsLlcMember   whfcl:TriplepointAcquisitionHoldingsLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 8,107          
Ending Fair Value $ 8,080   $ 8,080   $ 8,107      
Investment, Identifier [Axis]: Turnberry Solutions, Inc.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   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 2          
Ending Fair Value $ 2   2   $ 2      
Investment, Identifier [Axis]: Turnberry Solutions, Inc.First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 5,857   $ 5,857   $ 5,885      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 5,902          
Ending Fair Value $ 5,872   5,872   $ 5,902      
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   $ 317   $ 317      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:TwinRidgeCrsLpMember   whfcl:TwinRidgeCrsLpMember      
Investment type whfcl:ClassCommonUnitsMember   whfcl:ClassCommonUnitsMember   whfcl:ClassCommonUnitsMember      
Beginning Fair Value     $ 264          
Ending Fair Value $ 343   343   $ 264      
Investment, Identifier [Axis]: UserZoom Technologies, Inc. First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 10,542   $ 10,542   $ 9,665      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 9,621          
Ending Fair Value $ 10,415   10,415   $ 9,621      
Investment, Identifier [Axis]: Vibration Mountings amp; Controls, Inc, Common Stock                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 95   $ 95          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Vibration Mountings & Controls, Inc.          
Investment type Common Stock   Common Stock          
Ending Fair Value $ 95   $ 95          
Investment, Identifier [Axis]: Vibration Mountings amp; Controls, Inc, First Lien Secured Delayed Draw Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Vibration Mountings & Controls, Inc.          
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember          
Investment, Identifier [Axis]: Vibration Mountings amp; Controls, Inc, First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Vibration Mountings & Controls, Inc.          
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember          
Investment, Identifier [Axis]: Vibration Mountings amp; Controls, Inc, First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,282   $ 6,282          
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     Vibration Mountings & Controls, Inc.          
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]          
Ending Fair Value $ 6,282   $ 6,282          
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Preferred Units                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:VistriaBlockedMgtInvestorLpMember   whfcl:VistriaBlockedMgtInvestorLpMember      
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember      
Beginning Fair Value     $ 15          
Ending Fair Value $ 15   $ 15   $ 15      
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Series A Units                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:VistriaBlockedMgtInvestorLpMember   whfcl:VistriaBlockedMgtInvestorLpMember      
Investment type whfcl:SeriesUnitsMember   whfcl:SeriesUnitsMember   whfcl:SeriesUnitsMember      
Beginning Fair Value     $ 308          
Ending Fair Value $ 47   47   $ 308      
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) - First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 12,170   $ 12,170   $ 12,154      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:WElectricIntermediateHoldingsLlcMember   whfcl:WElectricIntermediateHoldingsLlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 12,334          
Ending Fair Value $ 12,303   12,303   $ 12,334      
Investment, Identifier [Axis]: WCHG Buyer, Inc.,First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 12,156   $ 12,156   $ 6,918      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:WchgBuyerInc.Member   whfcl:WchgBuyerInc.Member      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 6,948          
Ending Fair Value $ 12,130   $ 12,130   $ 6,948      
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 Investments   Equity Investments   Equity Investments      
Dividends, interest and PIK included in income     $ 2,527   $ 5,336      
Beginning Fair Value     21,602 22,741 22,741      
Gross Additions     460          
Net Change in Unrealized Appreciation (Depreciation)     299   (1,139)      
Ending Fair Value $ 22,361   22,361   21,602      
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Interests                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 21,564   $ 21,564   $ 21,104      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:WHFSTRSOhioSeniorLoanFundLLCMember   whfcl:WHFSTRSOhioSeniorLoanFundMember      
Investment type whfcl:LLCInterestsMember   whfcl:LLCInterestsMember   whfcl:LLCInterestsMember      
Beginning Fair Value     $ 21,602          
Ending Fair Value $ 22,361   22,361   $ 21,602      
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Subordinated Note                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 86,256   $ 86,256   $ 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   Subordinated Notes      
Dividends, interest and PIK included in income     $ 4,309   $ 9,070      
Beginning Fair Value     84,416 84,416 84,416      
Gross Additions     1,840          
Ending Fair Value $ 86,256   $ 86,256   $ 84,416      
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   whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember      
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember      
Beginning Fair Value     $ 1          
Ending Fair Value $ (1)   (1)   $ 1      
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Revolving Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 443   $ 443   $ 340      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember   whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 346          
Ending Fair Value $ 447   447   $ 346      
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Term Loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 6,991   $ 6,991   $ 7,045      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember   whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 7,100          
Ending Fair Value $ 7,027   7,027   $ 7,100      
Investment, Identifier [Axis]: What If Media Group, LLC Common Units                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment $ 851   $ 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   whfcl:CommonUnitsMember      
Beginning Fair Value     $ 1,963          
Ending Fair Value $ 1,961   $ 1,961   $ 1,963      
Investment, Identifier [Axis]: Whitestone Home Furnishings, LLC (d/b/a Saatva, Inc.) First Lien Secured Revolving Loan                
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:WhitestoneHomeFurnishingsLlcMember          
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 5   $ 5          
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 $ 4,638   $ 4,638   $ 2,832      
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]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 2,848          
Ending Fair Value $ 4,671   $ 4,671   $ 2,848      
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   whfcl:ZephyrBuyerL.p.Member      
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember      
Beginning Fair Value     $ 32          
Ending Fair Value $ 29   29   $ 32      
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 $ 13,609   $ 13,609   $ 13,701      
Schedule of investments in and advances to affiliated and controlled persons                
Issuer name     whfcl:ZephyrBuyerL.p.Member   whfcl:ZephyrBuyerL.p.Member      
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]      
Beginning Fair Value     $ 13,945          
Ending Fair Value $ 13,828   13,828   $ 13,945      
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
Telestream Holdings Corporation | First lien secured term loan and revolver loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment   $ 18,547   18,547        
MSI Information Services, Inc. | First lien secured term loan and revolver loan                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment             $ 9,602  
MSI Information Services, Inc. | First lien secured investments                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment             $ 2,111  
Alvaria Holdco | First Lien Secured Term Loan [Member]                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment           $ 1,682    
Alvaria Holdco | First lien secured investments                
Investments in and Advances to Affiliates [Line Items]                
Cost of investment           $ 11,182    
Non-controlled affiliate company investments                
Schedule of investments in and advances to affiliated and controlled persons                
Investment type         whfcl:PriorityFirstLienSecuredTermLoanMember      
Dividends, interest and PIK included in income     575   $ 891      
Beginning Fair Value     36,042 29,851 29,851      
Gross Additions     706   9,431      
Gross Reductions     (132)   (363)      
Net Change in Unrealized Appreciation (Depreciation) 4,885 (1,456) 2,515 (775) (2,877)      
Ending Fair Value 39,131   39,131   36,042      
Controlled affiliate company investments                
Schedule of investments in and advances to affiliated and controlled persons                
Dividends, interest and PIK included in income     6,836   14,406      
Beginning Fair Value     106,018 107,530 107,530      
Gross Additions     2,300          
Net Realized Gain (Loss)         (20,980)      
Net Change in Unrealized Appreciation (Depreciation) 648 $ 20,378 299 $ 19,563 19,468      
Ending Fair Value $ 108,617   $ 108,617   $ 106,018