v3.25.4
INVESTMENTS - Affiliated and Controlled Persons (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2025
USD ($)
Dec. 31, 2025
CAD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2024
CAD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2025
CAD ($)
Oct. 31, 2025
USD ($)
Sep. 30, 2025
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2024
CAD ($)
Sep. 30, 2024
USD ($)
Investments in and Advances to Affiliates [Line Items]                      
Weighted average remaining term of debt investments 3 years 3 months 18 days 3 years 3 months 18 days 3 years 3 years              
Cost basis of non-accrual loans $ 19,665,000   $ 69,576,000                
Fair value of non-accrual loans 10,561,000   37,019,000                
Cost of investment 607,574,000   695,240,000                
Paydown received under investments 166,468,000   $ 186,251,000   $ 128,199,000            
Schedule of investments in and advances to affiliated and controlled persons                      
Investment type     Warrant             Warrant  
Beginning Fair Value 642,213,000                    
Net Change in Unrealized Appreciation (Depreciation) 24,102,000   $ (9,567,000)   (21,969,000)            
Ending Fair Value 578,649,000   642,213,000                
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 78,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:AbCentersAcquisitionCorporationMember whfcl:AbCentersAcquisitionCorporationMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 80,000                    
Ending Fair Value     $ 80,000                
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  
Beginning Fair Value 5,000                    
Ending Fair Value     $ 5,000                
Investment, Identifier [Axis]: AB Centers Acquisition Corporation First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 7,866,000                
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]  
Beginning Fair Value 7,919,000                    
Ending Fair Value     $ 7,919,000                
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 405,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AbCentersAcquisitionCorporationMember whfcl:AbCentersAcquisitionCorporationMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 409,000                    
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          
Ending Fair Value $ 5,000                    
Investment, Identifier [Axis]: AB Centers Acquisition Corporation, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 12,922,000                    
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]          
Ending Fair Value $ 12,973,000                    
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 $ 20,227,000   $ 20,142,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ABBCon-ciseOpticalGroupLLCMember whfcl:ABBCon-ciseOpticalGroupLLCMember 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 19,535,000                    
Ending Fair Value 20,026,000   $ 19,535,000                
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 whfcl:ApgLionsPurchaserLlcMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 15,000                    
Ending Fair Value     $ 15,000                
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  
Beginning Fair Value 6,000                    
Ending Fair Value     $ 6,000                
Investment, Identifier [Axis]: APG Lions Purchaser, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,027,000                
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]  
Beginning Fair Value $ 4,070,000                    
Ending Fair Value     $ 4,070,000                
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 whfcl:ApgLionsPurchaserLlcMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 15,000                    
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          
Ending Fair Value $ 6,000                    
Investment, Identifier [Axis]: APG Lions Purchaser, LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,002,000                    
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]          
Ending Fair Value $ 4,046,000                    
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,615,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     Alvaria Holdco Alvaria Holdco              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 1,456,000                    
Ending Fair Value     $ 1,456,000                
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.) First Lien Secured Term Loan Two                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 9,318,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     Alvaria Holdco Alvaria Holdco              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 3,990,000                    
Ending Fair Value     $ 3,990,000                
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.), First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,029,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     Alvaria Holdco Alvaria Holdco              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 451,000                    
Ending Fair Value     $ 451,000                
Investment, Identifier [Axis]: Alvaria Holdco (Cayman) (d/b/a Aspect Software, Inc.), First Lien Secured Term Loan Three                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 2,330,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     Alvaria Holdco Alvaria Holdco              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 74,000                    
Ending Fair Value     $ 74,000                
Investment, Identifier [Axis]: American Crafts Holdings, LLC, Warrants                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsHoldingsLlcMember whfcl:AmericanCraftsHoldingsLlcMember whfcl:AmericanCraftsHoldingsLlcMember whfcl:AmericanCraftsHoldingsLlcMember              
Investment type Warrant   Warrant     Warrant       Warrant  
Investment, Identifier [Axis]: American Crafts Lc Super Priority First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 2,094,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember              
Investment type whfcl:SuperPriorityFirstLienSecuredTermLoanMember   whfcl:SuperPriorityFirstLienSecuredTermLoanMember     whfcl:SuperPriorityFirstLienSecuredTermLoanMember       whfcl:SuperPriorityFirstLienSecuredTermLoanMember  
Dividends, interest and PIK included in income     $ 187,000                
Beginning Fair Value     1,878,000                
Gross Additions     191,000                
Net Realized Gain (Loss) $ (2,094,000)                    
Net Change in Unrealized Appreciation (Depreciation) $ 2,094,000   (2,069,000)                
Ending Fair Value         1,878,000            
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,458,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value     $ 93,000                
Net Realized Gain (Loss) $ (1,458,000)                    
Net Change in Unrealized Appreciation (Depreciation) $ 1,458,000   (93,000)                
Ending Fair Value         93,000            
Investment, Identifier [Axis]: American Crafts, LC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 8,720,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value     $ 553,000                
Net Realized Gain (Loss) $ (8,720,000)                    
Net Change in Unrealized Appreciation (Depreciation) $ 8,720,000   (553,000)                
Ending Fair Value         553,000            
Investment, Identifier [Axis]: American Crafts, LC Priority First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 5,105,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember              
Investment type whfcl:PriorityFirstLienSecuredTermLoanMember   whfcl:PriorityFirstLienSecuredTermLoanMember     whfcl:PriorityFirstLienSecuredTermLoanMember       whfcl:PriorityFirstLienSecuredTermLoanMember  
Dividends, interest and PIK included in income     $ (10,000)                
Beginning Fair Value     3,226,000                
Net Realized Gain (Loss) $ (5,105,000)                    
Net Change in Unrealized Appreciation (Depreciation) $ 5,105,000   (3,226,000)                
Ending Fair Value         3,226,000            
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 2,374,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember              
Investment type whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember     whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember       whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember  
Dividends, interest and PIK included in income     $ 107,000                
Beginning Fair Value $ 373,000                    
Gross Additions     2,374,000                
Net Realized Gain (Loss) (2,373,000)                    
Net Change in Unrealized Appreciation (Depreciation) $ 2,000,000   (2,001,000)                
Ending Fair Value     373,000                
Investment, Identifier [Axis]: American Crafts, LC Super Senior Priority First Lien Secured Term Loan one                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,230,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember whfcl:AmericanCraftsLCMember              
Investment type whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember   whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember     whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember       whfcl:SuperSeniorPriorityFirstLienSecuredTermLoanMember  
Dividends, interest and PIK included in income     $ 96,000                
Gross Additions     1,230,000                
Net Realized Gain (Loss) $ (1,230,000)                    
Net Change in Unrealized Appreciation (Depreciation) 1,230,000   $ (1,230,000)                
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 $ 2,339,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ApollonHoldingsLlcMember whfcl:ApollonHoldingsLlcMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 2,442,000                    
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 $ 6,542,000                    
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]          
Ending Fair Value $ 6,632,000                    
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 whfcl:ArcserveCaymanGpLlcMember whfcl:ArcserveCaymanGpLlcMember              
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonUnitsMember  
Investment, Identifier [Axis]: Arcserve Cayman GP LLC (d/b/a Arcserve (USA), LLC) Common Units One                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ArcserveCaymanGpLlcMember whfcl:ArcserveCaymanGpLlcMember                  
Investment type 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 $ 775,000   $ 677,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Dividends, interest and PIK included in income $ 120,000   $ 116,000                
Beginning Fair Value 1,247,000                    
Gross Additions 98,000   677,000                
Net Change in Unrealized Appreciation (Depreciation) (105,000)   570,000                
Ending Fair Value 1,240,000   1,247,000                
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 $ 627,000   $ 569,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember              
Investment type whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember     whfcl:UnsecuredLoanMember       whfcl:UnsecuredLoanMember  
Dividends, interest and PIK included in income $ 58,000   $ 54,000                
Beginning Fair Value 581,000                    
Gross Additions 58,000   569,000                
Net Change in Unrealized Appreciation (Depreciation) (3,000)   12,000                
Ending Fair Value 636,000   581,000                
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 $ 642,000   $ 583,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember whfcl:ArcserveCaymanOpcoLpMember              
Investment type whfcl:UnsecuredLoanMember   whfcl:UnsecuredLoanMember     whfcl:UnsecuredLoanMember       whfcl:UnsecuredLoanMember  
Dividends, interest and PIK included in income $ 59,000   $ (55,000)                
Beginning Fair Value 594,000                    
Gross Additions 58,000   583,000                
Net Change in Unrealized Appreciation (Depreciation) (2,000)   11,000                
Ending Fair Value 650,000   594,000                
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 $ 19,568,000   $ 19,568,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ArcserveCaymanTopcoLpMember whfcl:ArcserveCaymanTopcoLpMember whfcl:ArcserveCaymanTopcoLpMember whfcl:ArcserveCaymanTopcoLpMember              
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonUnitsMember  
Beginning Fair Value $ 9,131,000                    
Gross Additions     $ 19,568,000                
Net Change in Unrealized Appreciation (Depreciation)     (10,437,000)                
Ending Fair Value $ 9,144,000   9,131,000                
Investment, Identifier [Axis]: Arcserve Cayman Topco LP (d/b/a Arcserve (USA), LLC) Common Units Two                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ArcserveCaymanTopcoLpMember whfcl:ArcserveCaymanTopcoLpMember                  
Investment type whfcl:CommonUnitsMember         whfcl:CommonUnitsMember          
Beginning Fair Value $ 9,131,000                    
Net Change in Unrealized Appreciation (Depreciation) 13,000                    
Ending Fair Value 9,144,000   $ 9,131,000                
Investment, Identifier [Axis]: Arteriocyte Medical Systems, Inc. First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:ArteriocyteMedicalSystemsInc.Member whfcl:ArteriocyteMedicalSystemsInc.Member              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 9,000                    
Ending Fair Value     $ 9,000                
Investment, Identifier [Axis]: Arteriocyte Medical Systems, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,877,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:ArteriocyteMedicalSystemsInc.Member whfcl:ArteriocyteMedicalSystemsInc.Member              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 5,021,000                    
Ending Fair Value     $ 5,021,000                
Investment, Identifier [Axis]: Atlas Parent, LLC Common Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,682,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:AtlasParentLlcMember whfcl:AtlasParentLlcMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 1,853,000                    
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 $ 544,000   $ 545,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group)              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 558,000                    
Ending Fair Value 546,000   $ 558,000                
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 $ 647,000   $ 648,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group)              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 652,000                    
Ending Fair Value 650,000   $ 652,000                
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     $ 287,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group)              
Investment type     whfcl:ClassALLCInterestsMember             whfcl:ClassALLCInterestsMember  
Beginning Fair Value 577,000                    
Ending Fair Value     $ 577,000                
Investment, Identifier [Axis]: Avision Holdings, LLC Class A LLC Interests                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 299,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Avision Holdings, LLC (d/b/a Avision Sales Group) Avision Holdings, LLC (d/b/a Avision Sales Group)                  
Investment type whfcl:ClassALLCInterestsMember         whfcl:ClassALLCInterestsMember          
Ending Fair Value $ 322,000                    
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 2,645,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 2,642,000                    
Ending Fair Value     $ 2,642,000                
Investment, Identifier [Axis]: BBQ Buyer, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 12,972,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 12,955,000                    
Ending Fair Value     $ 12,955,000                
Investment, Identifier [Axis]: BBQ Buyer, LLC Shares                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,100,000   $ 1,100,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember whfcl:BBQBuyerLLCMember              
Investment type Common Stock   whfcl:SharesMember     Common Stock       whfcl:SharesMember  
Beginning Fair Value $ 907,000                    
Ending Fair Value 1,003,000   $ 907,000                
Investment, Identifier [Axis]: BL Products Parent, LP Class A Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 788,000   $ 788,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BLProductsParentLPMember whfcl:BLProductsParentLPMember whfcl:BLProductsParentLPMember whfcl:BLProductsParentLPMember              
Investment type whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember     whfcl:ClassAUnitsMember       whfcl:ClassAUnitsMember  
Beginning Fair Value $ 1,012,000                    
Ending Fair Value 561,000   $ 1,012,000                
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     $ 942,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BPII-JLGroupHoldingsLPMember whfcl:BPII-JLGroupHoldingsLPMember              
Investment type     whfcl:ClassAUnitsMember             whfcl:ClassAUnitsMember  
Beginning Fair Value 1,400,000                    
Ending Fair Value     $ 1,400,000                
Investment, Identifier [Axis]: BPII-JL Group Holdings LP Class A Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 942,000                    
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          
Ending Fair Value $ 1,645,000                    
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 $ 270,000   $ 447,000                
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.) 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       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 461,000                    
Ending Fair Value 283,000   $ 461,000                
Investment, Identifier [Axis]: BUSA Acquisition Co. (d/b/a BankCard USA Merchant Services Inc.) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 7,231,000   $ 7,580,000                
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.) 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 7,691,000                    
Ending Fair Value 7,331,000   $ 7,691,000                
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,845,000   $ 1,472,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 1,477,000                    
Ending Fair Value 1,766,000   $ 1,477,000                
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 166,000   $ 412,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 415,000                    
Ending Fair Value 118,000   $ 415,000                
Investment, Identifier [Axis]: Banner Acquisition Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,912,000   $ 2,974,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember whfcl:BannerAcquisitionHoldingsLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 2,981,000                    
Ending Fair Value 2,787,000   $ 2,981,000                
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 367,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BarrettPurchaserLlcMember whfcl:BarrettPurchaserLlcMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 366,000                    
Investment, Identifier [Axis]: Barrett Purchaser LLC (d/b/a SIB Development and Consulting, Inc.) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,523,000                    
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]          
Ending Fair Value $ 3,493,000                    
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BarrettPurchaserLlcMember whfcl:BarrettPurchaserLlcMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value (2,000)                    
Ending Fair Value     $ (2,000)                
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 58,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BarrettPurchaserLlcMember whfcl:BarrettPurchaserLlcMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 63,000                    
Ending Fair Value     $ 63,000                
Investment, Identifier [Axis]: Barrett Purchaser LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 3,543,000                
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]  
Beginning Fair Value 3,574,000                    
Ending Fair Value     $ 3,574,000                
Investment, Identifier [Axis]: Basel U.S. Acquisition Co., Inc. First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BaselU.s.AcquisitionCo.Inc.Member whfcl:BaselU.s.AcquisitionCo.Inc.Member              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 7,000                    
Ending Fair Value     $ 7,000                
Investment, Identifier [Axis]: Basel U.S. Acquisition Co., Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 3,633,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BaselU.s.AcquisitionCo.Inc.Member whfcl:BaselU.s.AcquisitionCo.Inc.Member              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 3,675,000                    
Ending Fair Value     $ 3,675,000                
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 237,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BridgepointHealthcareLLCMember whfcl:BridgepointHealthcareLLCMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 231,000                    
Ending Fair Value     $ 231,000                
Investment, Identifier [Axis]: Bridgepoint Healthcare, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 8,457,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:BridgepointHealthcareLLCMember whfcl:BridgepointHealthcareLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,429,000                    
Ending Fair Value     $ 8,429,000                
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 whfcl:BuckeyeAcquirorLlcMember                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,281,000   $ 2,120,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 2,183,000                    
Ending Fair Value 2,323,000   $ 2,183,000                
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 365,000   $ 230,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 248,000                    
Ending Fair Value 379,000   $ 248,000                
Investment, Identifier [Axis]: Buckeye Acquiror LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,733,000   $ 6,774,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember whfcl:BuckeyeAcquirorLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 6,952,000                    
Ending Fair Value 6,834,000   $ 6,952,000                
Investment, Identifier [Axis]: CX Holdco LLC Common Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,116,000   $ 1,116,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CXHoldcoLLCMember whfcl:CXHoldcoLLCMember whfcl:CXHoldcoLLCMember whfcl:CXHoldcoLLCMember              
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonUnitsMember  
Beginning Fair Value $ 2,232,000                    
Ending Fair Value 218,000   $ 2,232,000                
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,135,000                    
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          
Gross Additions $ 1,135,000                    
Net Change in Unrealized Appreciation (Depreciation) (939,000)                    
Ending Fair Value 196,000                    
Investment, Identifier [Axis]: Camarillo Fitness Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 10,231,000   $ 10,269,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Camarillo Fitness Holdings, LLC [Member] Camarillo Fitness Holdings, LLC [Member] 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]       First Lien Secured Term Loan [Member]  
Dividends, interest and PIK included in income $ (38,000)   $ 36,000                
Beginning Fair Value 10,492,000                    
Gross Additions     10,270,000                
Gross Reductions (39,000)                    
Net Change in Unrealized Appreciation (Depreciation) (5,099,000)   222,000                
Ending Fair Value 5,354,000   10,492,000                
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     $ 10,325,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:CampFacilityServicesHoldingsLLCMember whfcl:CampFacilityServicesHoldingsLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 9,905,000                    
Ending Fair Value     $ 9,905,000                
Investment, Identifier [Axis]: Camp Facility Services Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 10,230,000                    
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]          
Ending Fair Value $ 9,781,000                    
Investment, Identifier [Axis]: Camp Facility Services Parent, LLC Preferred Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 840,000   $ 840,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CampFacilityServicesParentLLCMember whfcl:CampFacilityServicesParentLLCMember whfcl:CampFacilityServicesParentLLCMember whfcl:CampFacilityServicesParentLLCMember              
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember     whfcl:PreferredUnitsMember       whfcl:PreferredUnitsMember  
Beginning Fair Value $ 162,000                    
Ending Fair Value 31,000   $ 162,000                
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 206,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 2,000                    
Ending Fair Value 205,000   $ 2,000                
Investment, Identifier [Axis]: Cennox Holdings Limited, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 721,000   $ 665,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember whfcl:CennoxHoldingsLimitedMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 643,000                    
Ending Fair Value 717,000   $ 643,000                
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 133,000   $ 29,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CennoxInc.Member whfcl:CennoxInc.Member whfcl:CennoxInc.Member whfcl:CennoxInc.Member              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 30,000                    
Ending Fair Value 129,000   $ 30,000                
Investment, Identifier [Axis]: Cennox, Inc, First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 676,000   $ 649,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CennoxInc.Member whfcl:CennoxInc.Member 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 611,000                    
Ending Fair Value 694,000   $ 611,000                
Investment, Identifier [Axis]: Cennox, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,485,000   $ 3,319,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:CennoxInc.Member whfcl:CennoxInc.Member 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 3,344,000                    
Ending Fair Value 3,369,000   $ 3,344,000                
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 $ 3,404,000   $ 3,342,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ChaseProductsCoMember whfcl:ChaseProductsCoMember whfcl:ChaseProductsCoMember whfcl:ChaseProductsCoMember              
Investment type whfcl:SecondLienSecuredTermLoanMember   whfcl:SecondLienSecuredTermLoanMember     whfcl:SecondLienSecuredTermLoanMember       whfcl:SecondLienSecuredTermLoanMember  
Dividends, interest and PIK included in income $ 385,000   $ 380,000                
Beginning Fair Value 3,342,000   2,793,000                
Gross Additions 157,000   380,000                
Gross Reductions (95,000)                    
Net Change in Unrealized Appreciation (Depreciation)     169,000                
Ending Fair Value 3,404,000   3,342,000   2,793,000            
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 561,000   $ 630,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 555,000                    
Ending Fair Value 498,000   $ 555,000                
Investment, Identifier [Axis]: Claridge Products and Equipment, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,123,000   $ 5,690,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:ClaridgeProductsandEquipmentLLCMember whfcl:CleanChoiceEnergyIncMember whfcl:CleanChoiceEnergyIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,085,000                    
Ending Fair Value 4,661,000   $ 5,085,000                
Investment, Identifier [Axis]: Clark Restaurant Service, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,919,000                
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]  
Beginning Fair Value 4,993,000                    
Ending Fair Value     $ 4,993,000                
Investment, Identifier [Axis]: Clark Restaurant Service, LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,889,000                    
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]          
Ending Fair Value $ 4,928,000                    
Investment, Identifier [Axis]: CleanChoice Energy, Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 15,802,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:CleanChoiceEnergyIncMember whfcl:CleanChoiceEnergyIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 16,032,000                    
Ending Fair Value     $ 16,032,000                
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:CoastalTelevisionBroadcastingGroupLLCMember whfcl:CoastalTelevisionBroadcastingGroupLLCMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 1,000                    
Ending Fair Value     $ 1,000                
Investment, Identifier [Axis]: Coastal Television Broadcasting Group LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 7,808,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:CoastalTelevisionBroadcastingGroupLLCMember whfcl:CoastalTelevisionBroadcastingGroupLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 7,832,000                    
Ending Fair Value     $ 7,832,000                
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 $ 287,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ColonnadeParentIncMember whfcl:ColonnadeParentIncMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 158,000                    
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 $ 2,988,000                    
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]          
Ending Fair Value $ 1,925,000                    
Investment, Identifier [Axis]: Drew Foam Companies Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 13,445,000                
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]  
Beginning Fair Value 13,437,000                    
Ending Fair Value     $ 13,437,000                
Investment, Identifier [Axis]: Drew Foam Companies Inc, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,331,000                    
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]          
Ending Fair Value $ 13,314,000                    
Investment, Identifier [Axis]: E-Phoenix Acquisition Co. Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 8,299,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:E-PhoenixAcquisitionCo.Inc.Member whfcl:E-PhoenixAcquisitionCo.Inc.Member              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,342,000                    
Ending Fair Value     $ 8,342,000                
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          
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ElmDebtcoLlcMember whfcl:ElmDebtcoLlcMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Investment, Identifier [Axis]: ELM DebtCo, LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,488,000                    
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]          
Ending Fair Value $ 5,488,000                    
Investment, Identifier [Axis]: Eddy Acquisitions, LLC (d/b/a EducationDynamics, LLC) Preferred Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 167,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:EddyAcquisitionsLLCMember whfcl:EddyAcquisitionsLLCMember              
Investment type     whfcl:PreferredUnitsMember             whfcl:PreferredUnitsMember  
Investment, Identifier [Axis]: Eddy Acquisitions, LLC Preferred Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 167,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:EddyAcquisitionsLLCMember whfcl:EddyAcquisitionsLLCMember                  
Investment type whfcl:PreferredUnitsMember         whfcl:PreferredUnitsMember          
Investment, Identifier [Axis]: Education Dynamics, LLC Senior Preferred Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 167,000   $ 167,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember              
Investment type whfcl:SeniorPreferredUnitsMember   whfcl:SeniorPreferredUnitsMember     whfcl:SeniorPreferredUnitsMember       whfcl:SeniorPreferredUnitsMember  
Beginning Fair Value $ 100,000                    
Ending Fair Value     $ 100,000                
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 358,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ (51,000)                    
Ending Fair Value 320,000   $ (51,000)                
Investment, Identifier [Axis]: EducationDynamics, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 12,532,000   $ 12,989,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember whfcl:EducationDynamicsLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 12,449,000                    
Ending Fair Value 12,137,000   $ 12,449,000                
Investment, Identifier [Axis]: Event Services America, Inc. (d/b/a Contemporary Services Corporation) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 6,857,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:EventServicesAmericaIncMember whfcl:EventServicesAmericaIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 7,070,000                    
Ending Fair Value     $ 7,070,000                
Investment, Identifier [Axis]: FGI Acquisition Corp. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 15,765,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:FgiAcquisitionCorpMember whfcl:FgiAcquisitionCorpMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 16,026,000                    
Ending Fair Value     $ 16,026,000                
Investment, Identifier [Axis]: FloWorks International LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 661,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Ending Fair Value $ 663,000                    
Investment, Identifier [Axis]: FloWorks International LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,248,000   $ 5,280,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember whfcl:FloworksInternationalLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,281,000                    
Ending Fair Value 5,262,000   $ 5,281,000                
Investment, Identifier [Axis]: Foodservices Brand Group, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 357,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:FoodservicesBrandGroupLlcMember whfcl:FoodservicesBrandGroupLlcMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 321,000                    
Ending Fair Value     $ 321,000                
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,981,000   $ 3,000,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 3,023,000                    
Ending Fair Value 2,993,000   $ 3,023,000                
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 617,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 5,000                    
Ending Fair Value 619,000   $ 5,000                
Investment, Identifier [Axis]: Forward Solutions, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,880,000   $ 8,937,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember whfcl:ForwardSolutionsLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,007,000                    
Ending Fair Value 8,914,000   $ 9,007,000                
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 248,000                    
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          
Ending Fair Value $ 272,000                    
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          
Ending Fair Value $ 8,000                    
Investment, Identifier [Axis]: Four Winds Health, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,286,000                    
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]          
Ending Fair Value $ 4,343,000                    
Investment, Identifier [Axis]: Future Payment Technologies, LP First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 19,160,000   $ 20,382,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:FuturePaymentTechnologiesLPMember whfcl:FuturePaymentTechnologiesLPMember whfcl:FuturePaymentTechnologiesLPMember whfcl:FuturePaymentTechnologiesLPMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 20,420,000                    
Ending Fair Value $ 19,175,000   $ 20,420,000                
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:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 10,000                    
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 First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 4,000                    
Investment, Identifier [Axis]: G-2 Lather Acquisition Corp. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,850,000                    
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]          
Ending Fair Value $ 3,873,000                    
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 $ 15,014,000                    
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]          
Ending Fair Value $ 15,129,000                    
Investment, Identifier [Axis]: Geo Logic Systems Ltd.First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:GeoLogicSystemsLtdMember whfcl:GeoLogicSystemsLtdMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 2,000                    
Ending Fair Value     $ 2,000                
Investment, Identifier [Axis]: Geo Logic Systems Ltd.First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 14,234,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:GeoLogicSystemsLtdMember whfcl:GeoLogicSystemsLtdMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 12,883,000                    
Ending Fair Value     $ 12,883,000                
Investment, Identifier [Axis]: Gulf Winds International Acquisition, LLC (d/b/a Gulf Winds International, Inc.) First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 596,000   $ 444,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 447,000                    
Ending Fair Value 584,000   $ 447,000                
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 $ 8,820,000   $ 8,811,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember whfcl:GulfWindsInternationalAcquisitionLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,857,000                    
Ending Fair Value $ 8,697,000   $ 8,857,000                
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 whfcl:HIGCamarilloLpMember whfcl:HIGCamarilloLpMember              
Investment type whfcl:LimitedPartnerInterestsMember   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 $ 1,150,000   $ 1,384,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 1,354,000                    
Ending Fair Value 1,154,000   $ 1,354,000                
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 698,000   $ 480,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 455,000                    
Ending Fair Value 701,000   $ 455,000                
Investment, Identifier [Axis]: HRG Management, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,588,000   $ 5,523,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember whfcl:HRGManagementLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,395,000                    
Ending Fair Value $ 4,602,000   $ 5,395,000                
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 4,000                    
Ending Fair Value 2,000   $ 4,000                
Investment, Identifier [Axis]: ITS Buyer Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,262,000   $ 3,286,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember whfcl:ITSBuyerIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 3,307,000                    
Ending Fair Value 3,271,000   $ 3,307,000                
Investment, Identifier [Axis]: ImageOne Industries, LLC Common A Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,000   $ 10,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ImageOneIndustriesLLCMember whfcl:ImageOneIndustriesLLCMember whfcl:ImageOneIndustriesLLCMember whfcl:ImageOneIndustriesLLCMember              
Investment type whfcl:CommonUnitsMember   whfcl:CommonAUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonAUnitsMember  
Beginning Fair Value $ 12,000                    
Ending Fair Value     $ 12,000                
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ImpactAdvisorsLlcMember whfcl:ImpactAdvisorsLlcMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 10,000                    
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ImpactAdvisorsLlcMember whfcl:ImpactAdvisorsLlcMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 4,000                    
Investment, Identifier [Axis]: Impact Advisors, LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,132,000                    
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]          
Ending Fair Value $ 4,169,000                    
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 [Member] Infotree Holdco LLC [Member]                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 2,000                    
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 [Member] Infotree Holdco LLC [Member]                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 1,000                    
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,899,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Infotree Holdco LLC [Member] Infotree Holdco LLC [Member]                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 2,907,000                    
Investment, Identifier [Axis]: Infotree Holdco LLC First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,484,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Infotree Holdco LLC [Member] Infotree Holdco LLC [Member]                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 2,492,000                    
Investment, Identifier [Axis]: JVMC Holdings Corp First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 13,789,000                
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]  
Beginning Fair Value 14,166,000                    
Ending Fair Value     $ 14,166,000                
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 884,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 910,000                    
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 $ 2,309,000   $ 2,326,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 2,343,000                    
Ending Fair Value 2,319,000   $ 2,343,000                
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 235,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 246,000                    
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Revolving Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 309,000   $ 513,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 522,000                    
Ending Fair Value 314,000   $ 522,000                
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 449,000                    
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]          
Ending Fair Value $ 454,000                    
Investment, Identifier [Axis]: Juniper Landscaping Holdings LLC First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 10,917,000   $ 11,000,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember whfcl:JuniperLandscapingHoldingsLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 11,078,000                    
Ending Fair Value $ 10,964,000   $ 11,078,000                
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 whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 9,000                    
Ending Fair Value 10,000   $ 9,000                
Investment, Identifier [Axis]: KORE Wireless Group Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,218,000   $ 6,256,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember whfcl:KoreWirelessGroupIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 6,323,000                    
Ending Fair Value 6,290,000   $ 6,323,000                
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 Kelso Industries LLC              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Investment, Identifier [Axis]: Kelso Industries LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,710,000   $ 3,539,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Kelso Industries LLC Kelso Industries LLC 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 3,539,000                    
Ending Fair Value 4,823,000   $ 3,539,000                
Investment, Identifier [Axis]: Keras Holdings, LLC Shares                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 496,000   $ 496,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:KerasHoldingsLLCMember whfcl:KerasHoldingsLLCMember whfcl:KerasHoldingsLLCMember whfcl:KerasHoldingsLLCMember              
Investment type Common Stock   whfcl:SharesMember     Common Stock       whfcl:SharesMember  
Beginning Fair Value $ 779,000                    
Ending Fair Value 446,000   $ 779,000                
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 whfcl:LINCSystemsLLCMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 3,000                    
Ending Fair Value     $ 3,000                
Investment, Identifier [Axis]: LINC Systems, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 8,114,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LINCSystemsLLCMember whfcl:LINCSystemsLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,155,000                    
Ending Fair Value     $ 8,155,000                
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 whfcl:LINCSystemsLLCMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Investment, Identifier [Axis]: LINC Systems, LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 7,895,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LINCSystemsLLCMember whfcl:LINCSystemsLLCMember                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 7,900,000                    
Investment, Identifier [Axis]: LSCS Holdings, Inc. Second Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,953,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LSCSHoldingsIncMember whfcl:LSCSHoldingsIncMember              
Investment type     whfcl:SecondLienSecuredTermLoanMember             whfcl:SecondLienSecuredTermLoanMember  
Beginning Fair Value 5,000,000                    
Ending Fair Value     $ 5,000,000                
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 5,020,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LabLogisticsLLCMember whfcl:LabLogisticsLLCMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 5,020,000                    
Ending Fair Value     $ 5,020,000                
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 437,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LabLogisticsLLCMember whfcl:LabLogisticsLLCMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 437,000                    
Ending Fair Value     $ 437,000                
Investment, Identifier [Axis]: Lab Logistics, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 5,381,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LabLogisticsLLCMember whfcl:LabLogisticsLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,383,000                    
Ending Fair Value     $ 5,383,000                
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 whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 10,000                    
Ending Fair Value 4,000   $ 10,000                
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,486,000   $ 12,981,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember whfcl:LeviathanIntermediateHoldcoLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 13,312,000                    
Ending Fair Value 13,584,000   $ 13,312,000                
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan A                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,119,000   $ 5,453,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember              
Investment type whfcl:FirstLienSecuredTermLoanAMember   whfcl:FirstLienSecuredTermLoanAMember     whfcl:FirstLienSecuredTermLoanAMember       whfcl:FirstLienSecuredTermLoanAMember  
Beginning Fair Value $ 5,461,000                    
Ending Fair Value 5,120,000   $ 5,461,000                
Investment, Identifier [Axis]: Lift Brands, Inc First Lien Secured Term Loan B                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,752,000   $ 1,592,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember whfcl:LiftBrandsIncMember              
Investment type whfcl:FirstLienSecuredTermLoanBMember   whfcl:FirstLienSecuredTermLoanBMember     whfcl:FirstLienSecuredTermLoanBMember       whfcl:FirstLienSecuredTermLoanBMember  
Beginning Fair Value $ 1,594,000                    
Ending Fair Value 1,753,000   $ 1,594,000                
Investment, Identifier [Axis]: LogicMonitor, Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 6,144,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 6,144,000                    
Ending Fair Value     $ 6,144,000                
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Ending Fair Value $ 5,000                    
Investment, Identifier [Axis]: LogicMonitor, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,130,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:LogicmonitorInc.Member whfcl:LogicmonitorInc.Member                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 8,186,000                    
Investment, Identifier [Axis]: Luxury Brand Holdings, Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,556,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:LuxuryBrandHoldingsIncMember whfcl:LuxuryBrandHoldingsIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 4,580,000                    
Ending Fair Value     $ 4,580,000                
Investment, Identifier [Axis]: M2S Group Intermediate Holdings, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,838,000   $ 9,119,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:M2sGroupIntermediateHoldingsIncMember whfcl:M2sGroupIntermediateHoldingsIncMember whfcl:M2sGroupIntermediateHoldingsIncMember whfcl:M2sGroupIntermediateHoldingsIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,453,000                    
Ending Fair Value 9,276,000   $ 9,453,000                
Investment, Identifier [Axis]: MBS Highway, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 9,122,000   $ 9,157,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MbsHighwayLlcMember whfcl:MbsHighwayLlcMember whfcl:MbsHighwayLlcMember whfcl:MbsHighwayLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,212,000                    
Ending Fair Value 9,184,000   $ 9,212,000                
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 $ 281,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name MGT Merger Target, LLC MGT Merger Target, LLC                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 300,000                    
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,300,000   $ 804,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name MGT Merger Target, LLC MGT Merger Target, LLC MGT Merger Target, LLC MGT Merger Target, LLC              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 817,000                    
Ending Fair Value 1,322,000   $ 817,000                
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 236,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     MGT Merger Target, LLC MGT Merger Target, LLC              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 249,000                    
Ending Fair Value     $ 249,000                
Investment, Identifier [Axis]: MGT Merger Target, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 7,040,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     MGT Merger Target, LLC MGT Merger Target, LLC              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 7,176,000                    
Ending Fair Value     $ 7,176,000                
Investment, Identifier [Axis]: MGT Merger Target, LLC First lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 705,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name MGT Merger Target, LLC MGT Merger Target, LLC                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 715,000                    
Investment, Identifier [Axis]: MGT Merger Target, LLC First lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,430,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name MGT Merger Target, LLC MGT Merger Target, LLC                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 8,567,000                    
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,043,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:MSIInformationServicesIncMember whfcl:MSIInformationServicesIncMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 945,000                    
Ending Fair Value     $ 945,000                
Investment, Identifier [Axis]: MSI Information Services, Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 8,552,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:MSIInformationServicesIncMember whfcl:MSIInformationServicesIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 7,871,000                    
Ending Fair Value     $ 7,871,000                
Investment, Identifier [Axis]: Mamp;M OpCo. LLC (d/b/a Escalent, Inc.) First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name M&M OpCo. LLC (d/b/a Escalent, Inc.) M&M OpCo. LLC (d/b/a Escalent, Inc.) 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       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 5,000                    
Ending Fair Value 4,000   $ 5,000                
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 $ 4,748,000   $ 4,823,000                
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.) 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 4,922,000                    
Ending Fair Value $ 4,827,000   $ 4,922,000                
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          
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          
Investment, Identifier [Axis]: Marki Microwave, LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,986,000                    
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]          
Ending Fair Value $ 5,985,000                    
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 whfcl:MarlinDTC-LSMidco2LLCMember whfcl:MarlinDTC-LSMidco2LLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ (38,000)                    
Ending Fair Value (39,000)   $ (38,000)                
Investment, Identifier [Axis]: Marlin DTC-LS Midco 2, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 18,019,000   $ 18,577,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MarlinDTC-LSMidco2LLCMember whfcl:MarlinDTC-LSMidco2LLCMember 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 17,865,000                    
Ending Fair Value 17,299,000   $ 17,865,000                
Investment, Identifier [Axis]: Max Solutions Inc. Common Stock                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 400,000   $ 400,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember              
Investment type Common Stock   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     $ 411,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 402,000                    
Ending Fair Value     $ 402,000                
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  
Beginning Fair Value (3,000)                    
Ending Fair Value     $ (3,000)                
Investment, Identifier [Axis]: Max Solutions, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 6,439,000                
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]  
Beginning Fair Value 6,324,000                    
Ending Fair Value     $ 6,324,000                
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 407,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MaxSolutionsIncMember whfcl:MaxSolutionsIncMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 408,000                    
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          
Ending Fair Value $ 1,000                    
Investment, Identifier [Axis]: Max Solutions, Inc., First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,392,000                    
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]          
Ending Fair Value $ 6,420,000                    
Investment, Identifier [Axis]: Maxor Acquisition, Inc. (d/b/a Maxor National Pharmacy Services, LLC) First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 930,000                    
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          
Ending Fair Value $ 942,000                    
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 938,000                
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  
Beginning Fair Value $ 938,000                    
Ending Fair Value     $ 938,000                
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          
Ending Fair Value $ 8,000                    
Investment, Identifier [Axis]: Maxor Acquisition, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,872,000   $ 4,898,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MaxorAcquisitionInc.Member whfcl:MaxorAcquisitionInc.Member 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 4,986,000                    
Ending Fair Value 4,974,000   $ 4,986,000                
Investment, Identifier [Axis]: Maxor Acquisition, Inc.First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:MaxorAcquisitionInc.Member whfcl:MaxorAcquisitionInc.Member              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 9,000                    
Ending Fair Value     $ 9,000                
Investment, Identifier [Axis]: Media Source, LLC (d/b/a Media Source Inc.) First Lien Secured Revolving Loan                      
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          
Dividends, interest and PIK included in income $ 4,000                    
Gross Additions 218,000                    
Gross Reductions (218,000)                    
Net Change in Unrealized Appreciation (Depreciation) 17,000                    
Ending Fair Value 17,000                    
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 $ 4,242,000                    
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]          
Dividends, interest and PIK included in income $ 139,000                    
Gross Additions 4,252,000                    
Gross Reductions (11,000)                    
Net Change in Unrealized Appreciation (Depreciation) 1,000                    
Ending Fair Value 4,242,000                    
Investment, Identifier [Axis]: Medical Device Inc First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:MedicalDeviceIncMember whfcl:MedicalDeviceIncMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 6,000                    
Ending Fair Value     $ 6,000                
Investment, Identifier [Axis]: Medical Device Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 2,584,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:MedicalDeviceIncMember whfcl:MedicalDeviceIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 2,660,000                    
Ending Fair Value     $ 2,660,000                
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 $ 333,000   $ 333                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MerrimanHoldingsLPMember whfcl:MerrimanHoldingsLPMember whfcl:MerrimanHoldingsLPMember whfcl:MerrimanHoldingsLPMember              
Investment type whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember     whfcl:ClassAUnitsMember       whfcl:ClassAUnitsMember  
Beginning Fair Value $ 368,000                    
Ending Fair Value $ 312,000   $ 368,000                
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 865,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 874,000                    
Ending Fair Value     $ 874,000                
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,145,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 1,160,000                    
Ending Fair Value     $ 1,160,000                
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,378,000   $ 13,449,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 12,465,000                    
Ending Fair Value 5,374,000   $ 12,465,000                
Investment, Identifier [Axis]: Meta Buyer LLC First Lien Secured Term Loan Two                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,653,000   $ 952,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember whfcl:MetaBuyerLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 962,000                    
Ending Fair Value 6,653,000   $ 962,000                
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 $ 629,000   $ 632,000                
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) 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       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 642,000                    
Ending Fair Value 639,000   $ 642,000                
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 $ 563,000   $ 319,000                
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) 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       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 328,000                    
Ending Fair Value 572,000   $ 328,000                
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 $ 9,051,000   $ 9,255,000                
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) 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,399,000                    
Ending Fair Value 9,193,000   $ 9,399,000                
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,562,000   $ 1,572,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 1,582,000                    
Ending Fair Value 1,553,000   $ 1,582,000                
Investment, Identifier [Axis]: Monarch Collective Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 9,073,000   $ 9,119,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember whfcl:MonarchCollectiveHoldingsLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,223,000                    
Ending Fair Value 9,061,000   $ 9,223,000                
Investment, Identifier [Axis]: Motivational CIV, LLC Class B Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,250,000   $ 1,250,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MotivationalCIVLLCMember whfcl:MotivationalCIVLLCMember whfcl:MotivationalCIVLLCMember whfcl:MotivationalCIVLLCMember              
Investment type whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember     whfcl:ClassBUnitsMember       whfcl:ClassBUnitsMember  
Ending Fair Value $ 774,000                    
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 626,000   $ 1,175,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 1,061,000                    
Ending Fair Value 637,000   $ 1,061,000                
Investment, Identifier [Axis]: Motivational Marketing, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,104,000   $ 10,449,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember whfcl:MotivationalMarketingLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,438,000                    
Ending Fair Value $ 13,135,000   $ 9,438,000                
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 whfcl:NmZHoldcoIncZepIncMember whfcl:NmZHoldcoIncZepIncMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 6,000                    
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 $ 10,293,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:NmZHoldcoIncZepIncMember whfcl:NmZHoldcoIncZepIncMember                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 10,378,000                    
Investment, Identifier [Axis]: NNA Services, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,060,000   $ 9,087,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:NNAServicesLLCMember whfcl:NNAServicesLLCMember whfcl:NNAServicesLLCMember whfcl:NNAServicesLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,941,000                    
Ending Fair Value 8,037,000   $ 8,941,000                
Investment, Identifier [Axis]: NPAV Lessor Corp. First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 719,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:NPAVLessorCorp.Member whfcl:NPAVLessorCorp.Member              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 660,000                    
Ending Fair Value     $ 660,000                
Investment, Identifier [Axis]: NPAV Lessor Corp. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 6,448,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:NPAVLessorCorp.Member whfcl:NPAVLessorCorp.Member              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 5,918,000                    
Ending Fair Value     $ 5,918,000                
Investment, Identifier [Axis]: NPAV Lessor Corp., First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 722,000                    
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          
Ending Fair Value $ 660,000                    
Investment, Identifier [Axis]: NPAV Lessor Corp., First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,493,000                    
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]          
Ending Fair Value $ 5,022,000                    
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 301,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:NavigaIncMember whfcl:NavigaIncMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 169,000                    
Ending Fair Value     $ 169,000                
Investment, Identifier [Axis]: Naviga Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 3,140,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:NavigaIncMember whfcl:NavigaIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 1,763,000                    
Ending Fair Value     $ 1,763,000                
Investment, Identifier [Axis]: New American Crafts Holdings, LLC Class A Units                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:NewAmericanCraftsHoldingsLlcMember whfcl:NewAmericanCraftsHoldingsLlcMember whfcl:NewAmericanCraftsHoldingsLlcMember whfcl:NewAmericanCraftsHoldingsLlcMember              
Investment type whfcl:ClassAUnitsMember   whfcl:ClassAUnitsMember     whfcl:ClassAUnitsMember       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 $ 10,077,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:IslandEnergyServicesLlcMember whfcl:IslandEnergyServicesLlcMember                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 10,158,000                    
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 30,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name PANOS Brands, LLC PANOS Brands, LLC PANOS Brands, LLC PANOS Brands, LLC              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 36,000                    
Ending Fair Value $ 6,000   $ 36,000                
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Revolving Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 27,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name PANOS Brands, LLC PANOS Brands, LLC PANOS Brands, LLC PANOS Brands, LLC              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 33,000                    
Ending Fair Value 6,000   $ 33,000                
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,441,000                
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]  
Beginning Fair Value 4,505,000                    
Ending Fair Value     $ 4,505,000                
Investment, Identifier [Axis]: PANOS Brands, LLC First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,414,000   $ 3,997,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name PANOS Brands, LLC PANOS Brands, LLC 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 4,054,000                    
Ending Fair Value 4,475,000   $ 4,054,000                
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 $ 3,973,000                    
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]          
Ending Fair Value $ 4,027,000                    
Investment, Identifier [Axis]: PFB Holdco, Inc Class A Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 24,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PfbHoldingCompanyLlcMember whfcl:PfbHoldingCompanyLlcMember              
Investment type     whfcl:ClassAUnitsMember             whfcl:ClassAUnitsMember  
Investment, Identifier [Axis]: PFB Holding Company, LLC Class A Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 24,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PFBHoldcoIncMember whfcl:PFBHoldcoIncMember                  
Investment type 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 whfcl:PgiParentLlcMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         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 $ 5,026,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PgiParentLlcMember whfcl:PgiParentLlcMember                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 5,026,000                    
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 867,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PltfrmCompaniesLlcMember whfcl:PltfrmCompaniesLlcMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 916,000                    
Ending Fair Value     $ 916,000                
Investment, Identifier [Axis]: PLTFRM Companies, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 7,757,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PltfrmCompaniesLlcMember whfcl:PltfrmCompaniesLlcMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 8,188,000                    
Ending Fair Value     $ 8,188,000                
Investment, Identifier [Axis]: Patagonia Holdco LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 12,839,000   $ 12,602,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PatagoniaHoldcoLLCMember whfcl:PatagoniaHoldcoLLCMember whfcl:PatagoniaHoldcoLLCMember whfcl:PatagoniaHoldcoLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 13,135,000                    
Ending Fair Value 11,603,000   $ 13,135,000                
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Delayed Draw Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 558,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PavementPartnersIntercoLLCMember whfcl:PavementPartnersIntercoLLCMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 569,000                    
Ending Fair Value     $ 569,000                
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Revolving Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 331,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PavementPartnersIntercoLLCMember whfcl:PavementPartnersIntercoLLCMember              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 341,000                    
Ending Fair Value     $ 341,000                
Investment, Identifier [Axis]: Pavement Partners Interco, LLC First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 5,015,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PavementPartnersIntercoLLCMember whfcl:PavementPartnersIntercoLLCMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,111,000                    
Ending Fair Value     $ 5,111,000                
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 whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 17,000                    
Ending Fair Value 9,000   $ 17,000                
Investment, Identifier [Axis]: Pirtek Holdco, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 12,284,000   $ 7,298,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember whfcl:PirtekHoldcoLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 7,425,000                    
Ending Fair Value 12,332,000   $ 7,425,000                
Investment, Identifier [Axis]: Playmonster Group Equity, Inc Common Stock                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 460,000   $ 460,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember              
Investment type Common Stock   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 $ 3,600,000   $ 3,600,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember whfcl:PlaymonsterGroupEquityIncMember              
Investment type us-gaap:PreferredStockMember   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 $ 3,661,000   $ 3,661,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 1,635,000   $ 1,363,000                
Net Change in Unrealized Appreciation (Depreciation) 94,000   272,000                
Ending Fair Value 1,729,000   1,635,000   1,363,000            
Investment, Identifier [Axis]: Playmonster Group LLC, Priority First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,438,000   $ 1,275,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember whfcl:PlaymonsterGroupLLCMember              
Investment type whfcl:PriorityFirstLienSecuredTermLoanMember   whfcl:PriorityFirstLienSecuredTermLoanMember     whfcl:PriorityFirstLienSecuredTermLoanMember       whfcl:PriorityFirstLienSecuredTermLoanMember  
Dividends, interest and PIK included in income $ 164,000   $ 157,000                
Beginning Fair Value 1,172,000   1,015,000                
Gross Additions 164,000   157,000                
Net Change in Unrealized Appreciation (Depreciation) 19,000                    
Ending Fair Value 1,355,000   1,172,000   1,015,000            
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,329,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PowerServiceGroupCrAcquisitionIncMember whfcl:PowerServiceGroupCrAcquisitionIncMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 1,354,000                    
Ending Fair Value     $ 1,354,000                
Investment, Identifier [Axis]: Power Service Group CR Acquisition Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 8,642,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:PowerServiceGroupCrAcquisitionIncMember whfcl:PowerServiceGroupCrAcquisitionIncMember              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,784,000                    
Ending Fair Value     $ 8,784,000                
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 whfcl:PressurizedHoldingsLlcMember whfcl:PressurizedHoldingsLlcMember              
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonUnitsMember  
Investment, Identifier [Axis]: Pressurized Holdings, LLC Preferred Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 4,537,000   $ 4,537,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PressurizedHoldingsLlcMember whfcl:PressurizedHoldingsLlcMember whfcl:PressurizedHoldingsLlcMember whfcl:PressurizedHoldingsLlcMember              
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember     whfcl:PreferredUnitsMember       whfcl:PreferredUnitsMember  
Beginning Fair Value $ 1,657,000   $ 251,000                
Net Change in Unrealized Appreciation (Depreciation) 3,127,000   1,406,000                
Ending Fair Value $ 4,784,000   $ 1,657,000   251,000            
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 whfcl:PrincipalLightingGroupLlcMember whfcl:PrincipalLightingGroupLlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Ending Fair Value $ 4,000                    
Investment, Identifier [Axis]: Principal Lighting Group, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,312,000   $ 3,479,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:PrincipalLightingGroupLlcMember whfcl:PrincipalLightingGroupLlcMember whfcl:PrincipalLightingGroupLlcMember whfcl:PrincipalLightingGroupLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 3,479,000                    
Ending Fair Value 3,343,000   $ 3,479,000                
Investment, Identifier [Axis]: Quest Events, LLC Common Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 385,000   $ 376,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Quest Events, LLC [Member] Quest Events, LLC [Member] Quest Events, LLC [Member] Quest Events, LLC [Member]              
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonUnitsMember  
Beginning Fair Value $ 149,000                    
Ending Fair Value     $ 149,000                
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 122,000                    
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          
Ending Fair Value $ 113,000                    
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Revolving Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 246,000                
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  
Beginning Fair Value 248,000                    
Ending Fair Value     $ 248,000                
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,258,000   $ 472,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Quest Events, LLC [Member] Quest Events, LLC [Member] 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 473,000                    
Ending Fair Value 1,187,000   $ 473,000                
Investment, Identifier [Axis]: Quest Events, LLC First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 11,563,000                
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]  
Beginning Fair Value 11,592,000                    
Ending Fair Value     $ 11,592,000                
Investment, Identifier [Axis]: Quest Events, LLC, First Lien Secured Revolving Loan, One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 288,000                    
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          
Ending Fair Value $ 262,000                    
Investment, Identifier [Axis]: Quest Events, LLC, First Lien Secured Term Loan, One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 11,655,000                    
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]          
Ending Fair Value $ 11,041,000                    
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,898,000   $ 2,922,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 2,946,000                    
Ending Fair Value 2,827,000   $ 2,946,000                
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  
Beginning Fair Value 11,000                    
Ending Fair Value     $ 11,000                
Investment, Identifier [Axis]: RCKC Acquisitions LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 10,747,000   $ 10,839,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember whfcl:RCKCAcquisitionsLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 10,923,000                    
Ending Fair Value $ 10,481,000   $ 10,923,000                
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          
Ending Fair Value $ (35,000)                    
Investment, Identifier [Axis]: RLJ Pro-Vac, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,546,000   $ 6,566,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:RLJPro-VacInc.Member whfcl:RLJPro-VacInc.Member 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 6,637,000                    
Ending Fair Value $ 6,396,000   $ 6,637,000                
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          
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 627,000                    
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          
Ending Fair Value $ 627,000                    
Investment, Identifier [Axis]: Rewards Network Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 10,036,000                    
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]          
Ending Fair Value $ 10,034,000                    
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.) 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       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 9,000                    
Ending Fair Value 12,000   $ 9,000                
Investment, Identifier [Axis]: Ribbon Communications Operating Company, Inc. (d/b/a Ribbon Communications Inc.) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,483,000   $ 8,600,000                
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.) 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,692,000                    
Ending Fair Value 8,631,000   $ 8,692,000                
Investment, Identifier [Axis]: Ross-Simons Topco, LP Preferred Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 514,000   $ 514,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:Ross-SimonsTopcoLPMember whfcl:Ross-SimonsTopcoLPMember whfcl:Ross-SimonsTopcoLPMember whfcl:Ross-SimonsTopcoLPMember              
Investment type whfcl:PreferredUnitsMember   whfcl:PreferredUnitsMember     whfcl:PreferredUnitsMember       whfcl:PreferredUnitsMember  
Beginning Fair Value $ 756,000                    
Ending Fair Value 735,000   $ 756,000                
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 293,000                    
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          
Ending Fair Value $ 319,000                    
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          
Ending Fair Value $ 25,000                    
Investment, Identifier [Axis]: SCIC Buyer, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 8,970,000                    
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]          
Ending Fair Value $ 9,142,000                    
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 $ 1,637,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SalonRepublicHoldingsLlcMember whfcl:SalonRepublicHoldingsLlcMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 1,653,000                    
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          
Ending Fair Value $ 8,000                    
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 $ 4,974,000                    
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]          
Ending Fair Value $ 5,021,000                    
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,641,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:SalonRepublicHoldingsLlcMember whfcl:SalonRepublicHoldingsLlcMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 1,672,000                    
Ending Fair Value     $ 1,672,000                
Investment, Identifier [Axis]: Salon Republic Holdings, 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  
Beginning Fair Value 13,000                    
Ending Fair Value     $ 13,000                
Investment, Identifier [Axis]: Salon Republic Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 4,988,000                
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]  
Beginning Fair Value 5,063,000                    
Ending Fair Value     $ 5,063,000                
Investment, Identifier [Axis]: Salon Republic Investments LLC, Common Stock                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 400,000   $ 400,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember              
Investment type Common Stock   Common Stock     Common Stock       Common Stock  
Beginning Fair Value $ 132,000                    
Ending Fair Value 6,000   $ 132,000                
Investment, Identifier [Axis]: Salon Republic Investments LLC, Preferred Stock                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 200,000   $ 200,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember whfcl:SalonRepublicInvestmentsLlcMember              
Investment type us-gaap:PreferredStockMember   us-gaap:PreferredStockMember     us-gaap:PreferredStockMember       us-gaap:PreferredStockMember  
Beginning Fair Value $ 242,000                    
Ending Fair Value $ 265,000   $ 242,000                
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 whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 5,000                    
Ending Fair Value     $ 5,000                
Investment, Identifier [Axis]: Sleep OpCo LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,259,000   $ 22,401,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember whfcl:SleepOpCoLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 22,441,000                    
Ending Fair Value 13,255,000   $ 22,441,000                
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,480,000                    
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]          
Ending Fair Value $ 7,281,000                    
Investment, Identifier [Axis]: Smalto Inc, First Lien Secured Term Loan One                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 936,000   $ 967,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SmaltoInc.Member whfcl:SmaltoInc.Member 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 978,000                    
Ending Fair Value 944,000   $ 978,000                
Investment, Identifier [Axis]: Smalto Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 6,682,000                
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]  
Beginning Fair Value 6,654,000                    
Ending Fair Value     $ 6,654,000                
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Class A Common Stock                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,941,000   $ 1,941,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember              
Investment type us-gaap:CommonClassAMember   whfcl:ClassCommonStockMember     us-gaap:CommonClassAMember       whfcl:ClassCommonStockMember  
Beginning Fair Value $ 173,000                    
Ending Fair Value 507,000   $ 173,000                
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc First Lien Secured Term Loan C                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,095,000   $ 1,819,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember              
Investment type whfcl:FirstLienSecuredTermLoanCMember   whfcl:FirstLienSecuredTermLoanCMember     whfcl:FirstLienSecuredTermLoanCMember       whfcl:FirstLienSecuredTermLoanCMember  
Beginning Fair Value $ 1,790,000                    
Ending Fair Value 2,098,000   $ 1,790,000                
Investment, Identifier [Axis]: Snap Fitness Holdings, Inc Warrants                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 793,000   $ 793,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember whfcl:SnapFitnessHoldingsIncMember              
Investment type Warrant   Warrant     Warrant       Warrant  
Beginning Fair Value $ 70,000                    
Ending Fair Value 205,000   $ 70,000                
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 3,839,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:SourceCodeHoldingsLLCMember whfcl:SourceCodeHoldingsLLCMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value 3,854,000                    
Ending Fair Value     $ 3,854,000                
Investment, Identifier [Axis]: Source Code Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 14,041,000                
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]  
Beginning Fair Value 14,095,000                    
Ending Fair Value     $ 14,095,000                
Investment, Identifier [Axis]: Source Code Holdings, LLC., First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,811,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SourceCodeHoldingsLLCMember whfcl:SourceCodeHoldingsLLCMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 3,831,000                    
Investment, Identifier [Axis]: Source Code Holdings, LLC., First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,935,000                    
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]          
Ending Fair Value $ 14,009,000                    
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 $ 404,000   $ 404,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:SterlingPureBlockerLlcMember whfcl:SterlingPureBlockerLlcMember whfcl:SterlingPureBlockerLlcMember whfcl:SterlingPureBlockerLlcMember              
Investment type whfcl:ClassBUnitsMember   whfcl:ClassBUnitsMember     whfcl:ClassBUnitsMember       whfcl:ClassBUnitsMember  
Beginning Fair Value $ 388,000                    
Ending Fair Value 57,000   $ 388,000                
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 987,000   $ 573,000                
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.) 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       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 577,000                    
Ending Fair Value 1,000,000   $ 577,000                
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 444,000   $ 574,000                
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.) 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       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 576,000                    
Ending Fair Value 450,000   $ 576,000                
Investment, Identifier [Axis]: Surge Amuze Holdings Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,596,000   $ 5,629,000                
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.) 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,643,000                    
Ending Fair Value 5,645,000   $ 5,643,000                
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 $ 1,084,000                    
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) 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       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ (1,000)                    
Ending Fair Value $ 1,091,000   $ (1,000)                
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) 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       whfcl:FirstLienSecuredRevolvingLoanMember  
Ending Fair Value $ 1,000                    
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 $ 9,000,000   $ 8,074,000                
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) 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,067,000                    
Ending Fair Value $ 9,023,000   $ 8,067,000                
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          
Investment, Identifier [Axis]: TVG I-EMSI Parent, LLC Class B Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,291,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TvgIEmsiParentLlcMember whfcl:TvgIEmsiParentLlcMember                  
Investment type whfcl:ClassBUnitsMember         whfcl:ClassBUnitsMember          
Gross Additions $ 3,291,000                    
Ending Fair Value 3,291,000                    
Investment, Identifier [Axis]: TableTrust Brands LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,453,000   $ 2,468,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TabletrustBrandsLlcMember whfcl:TabletrustBrandsLlcMember whfcl:TabletrustBrandsLlcMember whfcl:TabletrustBrandsLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 2,468,000                    
Ending Fair Value $ 2,480,000   $ 2,468,000                
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 1,051,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Telestream Holdings Corporation Telestream Holdings Corporation Telestream Holdings Corporation Telestream Holdings Corporation              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 1,009,000                    
Ending Fair Value 20,000   $ 1,009,000                
Investment, Identifier [Axis]: Telestream Holdings Corporation First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 11,437,000   $ 17,496,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Telestream Holdings Corporation Telestream Holdings Corporation Telestream Holdings Corporation Telestream Holdings Corporation              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 17,063,000                    
Ending Fair Value 11,437,000   $ 17,063,000                
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 $ 7,109,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TelestreamTopco2LlcMember whfcl:TelestreamTopco2LlcMember                  
Investment type whfcl:CommonUnitsMember         whfcl:CommonUnitsMember          
Ending Fair Value $ 8,027,000                    
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TexasExpressWashLlcMember whfcl:TexasExpressWashLlcMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 100,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TexasExpressWashLlcMember whfcl:TexasExpressWashLlcMember                  
Investment type whfcl:SecondLienSecuredTermLoanMember         whfcl:SecondLienSecuredTermLoanMember          
Ending Fair Value $ 100,000                    
Investment, Identifier [Axis]: Texas Express Wash, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 10,778,000                    
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]          
Ending Fair Value $ 10,776,000                    
Investment, Identifier [Axis]: Texas Express Wash, LLC Second Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,436,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TexasExpressWashLlcMember whfcl:TexasExpressWashLlcMember                  
Investment type whfcl:SecondLienSecuredTermLoanMember         whfcl:SecondLienSecuredTermLoanMember          
Ending Fair Value $ 1,435,000                    
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 $ 197,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TexasWashHoldingsLlcMember whfcl:TexasWashHoldingsLlcMember                  
Investment type Warrant         Warrant          
Ending Fair Value $ 197,000                    
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Delayed Draw Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 793,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ImpactAdvisorsLlcMember whfcl:ImpactAdvisorsLlcMember                  
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember         whfcl:FirstLienSecuredDelayedDrawLoanMember          
Ending Fair Value $ 806,000                    
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 308,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:ImpactAdvisorsLlcMember whfcl:ImpactAdvisorsLlcMember                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 317,000                    
Investment, Identifier [Axis]: The Crom Corporation First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 3,998,000                    
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]          
Ending Fair Value $ 4,049,000                    
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 795,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 761,000                    
Ending Fair Value (132,000)   $ 761,000                
Investment, Identifier [Axis]: The Kyjen Company, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 11,400,000   $ 11,309,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember whfcl:TheKyjenCompanyLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 10,895,000                    
Ending Fair Value 9,790,000   $ 10,895,000                
Investment, Identifier [Axis]: Token Buyer, Inc First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 1,363,000   $ 6,709,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TokenBuyerIncMember whfcl:TokenBuyerIncMember whfcl:TokenBuyerIncMember whfcl:TokenBuyerIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,658,000                    
Ending Fair Value $ 1,199,000   $ 5,658,000                
Investment, Identifier [Axis]: Trailhead Media LLC First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Trailhead Media LLC Trailhead Media LLC Trailhead Media LLC Trailhead Media LLC              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Ending Fair Value $ (3,000)                    
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Trailhead Media LLC Trailhead Media LLC Trailhead Media LLC Trailhead Media LLC              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Ending Fair Value $ (3,000)                    
Investment, Identifier [Axis]: Trailhead Media LLC, First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,553,000   $ 6,548,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name Trailhead Media LLC Trailhead Media LLC Trailhead Media LLC Trailhead Media LLC              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 6,548,000                    
Ending Fair Value 6,532,000   $ 6,548,000                
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 $ 7,586,000   $ 8,481,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TranserviceHoldingsIncMember whfcl:TranserviceHoldingsIncMember whfcl:TranserviceHoldingsIncMember whfcl:TranserviceHoldingsIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 8,715,000                    
Ending Fair Value $ 7,701,000   $ 8,715,000                
Investment, Identifier [Axis]: Trimlite Buyer LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment           $ 14,957       $ 15,006  
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TrimliteBuyerLLCMember whfcl:TrimliteBuyerLLCMember whfcl:TrimliteBuyerLLCMember whfcl:TrimliteBuyerLLCMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value   $ 13,206                  
Ending Fair Value $ 13,748,000     $ 13,206              
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember              
Investment type     whfcl:FirstLienSecuredDelayedDrawLoanMember             whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 9,000                    
Ending Fair Value     $ 9,000                
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 whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 12,000                    
Ending Fair Value 18,000   $ 12,000                
Investment, Identifier [Axis]: TriplePoint Acquisition Holdings LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 7,975,000   $ 5,254,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember whfcl:TriplepointAcquisitionHoldingsLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,338,000                    
Ending Fair Value 8,107,000   $ 5,338,000                
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  
Beginning Fair Value 4,000                    
Ending Fair Value     $ 4,000                
Investment, Identifier [Axis]: Turnberry Solutions, Inc.First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 5,924,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     whfcl:TurnberrySolutionsInc.Member whfcl:TurnberrySolutionsInc.Member              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 5,964,000                    
Ending Fair Value     $ 5,964,000                
Investment, Identifier [Axis]: Turnberry Solutions., First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TurnberrySolutionsInc.Member whfcl:TurnberrySolutionsInc.Member                  
Investment type whfcl:FirstLienSecuredRevolvingLoanMember         whfcl:FirstLienSecuredRevolvingLoanMember          
Ending Fair Value $ 2,000                    
Investment, Identifier [Axis]: Turnberry Solutions., First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 5,885,000                    
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]          
Ending Fair Value $ 5,902,000                    
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 $ 317,000   $ 317,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:TwinRidgeCrsLpMember whfcl:TwinRidgeCrsLpMember whfcl:TwinRidgeCrsLpMember whfcl:TwinRidgeCrsLpMember              
Investment type whfcl:ClassCommonUnitsMember   whfcl:ClassCommonUnitsMember     whfcl:ClassCommonUnitsMember       whfcl:ClassCommonUnitsMember  
Beginning Fair Value $ 350,000                    
Ending Fair Value 264,000   $ 350,000                
Investment, Identifier [Axis]: UserZoom Technologies, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 9,665,000   $ 9,618,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:UserzoomTechnologiesIncMember whfcl:UserzoomTechnologiesIncMember whfcl:UserzoomTechnologiesIncMember whfcl:UserzoomTechnologiesIncMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 9,809,000                    
Ending Fair Value $ 9,621,000   $ 9,809,000                
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          
Ending Fair Value $ 15,000                    
Investment, Identifier [Axis]: Vistria Blocked MGT Investor, LP (d/b/a MGT Consulting Group) Series A Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment     $ 314,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:VistriaBlockedMgtInvestorLpMember whfcl:VistriaBlockedMgtInvestorLpMember whfcl:VistriaBlockedMgtInvestorLpMember whfcl:VistriaBlockedMgtInvestorLpMember              
Investment type whfcl:SeriesUnitsMember   whfcl:SeriesUnitsMember     whfcl:SeriesUnitsMember       whfcl:SeriesUnitsMember  
Beginning Fair Value $ 493,000                    
Ending Fair Value 308,000   $ 493,000                
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) - First Lien Secured Revolving Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation)              
Investment type     whfcl:FirstLienSecuredRevolvingLoanMember             whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value 9,000                    
Ending Fair Value     $ 9,000                
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     $ 12,124,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name     W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation)              
Investment type     First Lien Secured Term Loan [Member]             First Lien Secured Term Loan [Member]  
Beginning Fair Value 12,216,000                    
Ending Fair Value     $ 12,216,000                
Investment, Identifier [Axis]: W Electric Intermediate Holdings, LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 12,154,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation) W Electric Intermediate Holdings, LLC (d/b/a Westinghouse Electric Corporation)                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 12,334,000                    
Investment, Identifier [Axis]: WCHG Buyer, Inc. First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 6,918,000                    
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WchgBuyerInc.Member whfcl:WchgBuyerInc.Member                  
Investment type First Lien Secured Term Loan [Member]         First Lien Secured Term Loan [Member]          
Ending Fair Value $ 6,948,000                    
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 whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember              
Investment type Equity (excluding STRS JV)   Equity (excluding STRS JV)     Equity (excluding STRS JV)       Equity (excluding STRS JV)  
Dividends, interest and PIK included in income $ 5,336,000   $ 6,861,000                
Beginning Fair Value 22,741,000   22,782,000                
Net Change in Unrealized Appreciation (Depreciation) (1,139,000)   (41,000)                
Ending Fair Value 21,602,000   22,741,000   22,782,000            
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Interests                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 21,104,000   $ 21,104,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WHFSTRSOhioSeniorLoanFundMember whfcl:WHFSTRSOhioSeniorLoanFundMember whfcl:WHFSTRSOhioSeniorLoanFundMember whfcl:WHFSTRSOhioSeniorLoanFundMember              
Investment type whfcl:LLCInterestsMember   whfcl:LLCInterestsMember     whfcl:LLCInterestsMember       whfcl:LLCInterestsMember  
Beginning Fair Value $ 22,741,000                    
Ending Fair Value 21,602,000   $ 22,741,000                
Investment, Identifier [Axis]: WHF STRS Ohio Senior Loan Fund LLC Subordinated Note                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 84,416,000   $ 84,416,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember whfcl:WHFSTRSOhioSeniorLoanFundLLCMember              
Investment type Subordinated Notes   Subordinated Notes     Subordinated Notes       Subordinated Notes  
Dividends, interest and PIK included in income $ 9,070,000   $ 9,838,000                
Beginning Fair Value 84,416,000   84,416,000                
Ending Fair Value $ 84,416,000   $ 84,416,000   84,416,000            
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Delayed Draw Loan                      
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember              
Investment type whfcl:FirstLienSecuredDelayedDrawLoanMember   whfcl:FirstLienSecuredDelayedDrawLoanMember     whfcl:FirstLienSecuredDelayedDrawLoanMember       whfcl:FirstLienSecuredDelayedDrawLoanMember  
Beginning Fair Value $ 2,000                    
Ending Fair Value 1,000   $ 2,000                
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Revolving Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 340,000   $ 253,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 254,000                    
Ending Fair Value 346,000   $ 254,000                
Investment, Identifier [Axis]: Wamp;A Intermediate Co., LLC First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 7,045,000   $ 7,548,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember whfcl:WakefieldAndAssociatesIntermediateCo.LlcMember 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]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 7,555,000                    
Ending Fair Value 7,100,000   $ 7,555,000                
Investment, Identifier [Axis]: What If Media Group, LLC Common Units                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 851,000   $ 851,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WhatIfMediaGroupLLCMember whfcl:WhatIfMediaGroupLLCMember whfcl:WhatIfMediaGroupLLCMember whfcl:WhatIfMediaGroupLLCMember              
Investment type whfcl:CommonUnitsMember   whfcl:CommonUnitsMember     whfcl:CommonUnitsMember       whfcl:CommonUnitsMember  
Beginning Fair Value $ 1,756,000                    
Ending Fair Value 1,963,000   $ 1,756,000                
Investment, Identifier [Axis]: Whitestone Home Furnishings, LLC (d/b/a Saatva, Inc.) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 2,832,000   $ 2,887,000                
Schedule of investments in and advances to affiliated and controlled persons                      
Issuer name whfcl:WhitestoneHomeFurnishingsLlcMember whfcl:WhitestoneHomeFurnishingsLlcMember whfcl:WhitestoneHomeFurnishingsLlcMember whfcl:WhitestoneHomeFurnishingsLlcMember              
Investment type First Lien Secured Term Loan [Member]   First Lien Secured Term Loan [Member]     First Lien Secured Term Loan [Member]       First Lien Secured Term Loan [Member]  
Beginning Fair Value $ 2,930,000                    
Ending Fair Value $ 2,848,000   $ 2,930,000                
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 whfcl:ZephyrBuyerL.p.Member whfcl:ZephyrBuyerL.p.Member              
Investment type whfcl:FirstLienSecuredRevolvingLoanMember   whfcl:FirstLienSecuredRevolvingLoanMember     whfcl:FirstLienSecuredRevolvingLoanMember       whfcl:FirstLienSecuredRevolvingLoanMember  
Beginning Fair Value $ 48,000                    
Ending Fair Value 32,000   $ 48,000                
Investment, Identifier [Axis]: Zephyr Buyer, L.P. (d/b/a The Weather Company, LLC) First Lien Secured Term Loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment $ 13,701,000                    
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]          
Ending Fair Value $ 13,945,000                    
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                     $ 17,816,000
Honors Holdings, LLC | First lien secured investments                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment                     7,582,000
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                     $ 10,234,000
Telestream Holdings Corporation | First lien secured term loan and revolver loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment                 $ 18,547,000    
MSI Information Services, Inc. | First lien secured investments                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment               $ 2,111,000      
MSI Information Services, Inc. | First lien secured term loan and revolver loan                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment               $ 9,602,000      
Alvaria Holdco | First Lien Secured Term Loan [Member]                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment             $ 1,682,000        
Alvaria Holdco | First lien secured investments                      
Investments in and Advances to Affiliates [Line Items]                      
Cost of investment             $ 11,182,000        
Non-controlled affiliate company investments                      
Schedule of investments in and advances to affiliated and controlled persons                      
Dividends, interest and PIK included in income 891,000   798,000                
Beginning Fair Value 29,851,000   5,422,000                
Gross Additions 9,431,000   32,204,000                
Gross Reductions (363,000)                    
Net Change in Unrealized Appreciation (Depreciation) (2,877,000)   (7,775,000)   (5,608,000)            
Ending Fair Value 36,042,000   29,851,000   5,422,000            
Controlled affiliate company investments                      
Schedule of investments in and advances to affiliated and controlled persons                      
Dividends, interest and PIK included in income 14,406,000   17,079,000                
Beginning Fair Value 107,530,000   112,948,000                
Gross Additions     3,795,000                
Net Realized Gain (Loss) (20,980,000)                    
Net Change in Unrealized Appreciation (Depreciation) 19,468,000   (9,213,000)   (8,490,000)            
Ending Fair Value $ 106,018,000   $ 107,530,000   $ 112,948,000