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CONSOLIDATED SCHEDULE OF INVESTMENTS - (Parenthetical)
€ in Millions, £ in Millions, $ in Millions, $ in Millions, $ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2023
USD ($)
Rate
Mar. 31, 2022
USD ($)
Dec. 31, 2022
USD ($)
Rate
Mar. 31, 2023
EUR (€)
Rate
Mar. 31, 2023
CAD ($)
Rate
Mar. 31, 2023
GBP (£)
Rate
Mar. 31, 2023
NZD ($)
Rate
Dec. 31, 2022
EUR (€)
Rate
Dec. 31, 2022
CAD ($)
Rate
Dec. 31, 2022
GBP (£)
Rate
Dec. 31, 2022
NZD ($)
Rate
Derivative Instruments Table [Abstract]                      
Derivative Asset, Counterparty Name [Extensible Enumeration]     Royal Bank of Canada         Royal Bank of Canada Royal Bank of Canada Royal Bank of Canada Royal Bank of Canada
Total $ 5.0                    
Total     $ 21.0                
Schedule of Investments [Line Items]                      
% of Net Assets 210.44%   227.97% 210.44% 210.44% 210.44% 210.44% 227.97% 227.97% 227.97% 227.97%
% of Total Assets 97.00%   97.00% 97.00% 97.00% 97.00% 97.00% 97.00% 97.00% 97.00% 97.00%
Net unrealized gain (loss) for federal tax purposes $ (300.0)   $ (200.0)                
Tax cost basis 21,500.0   22,000.0                
Aggregate gross unrealized loss for federal tax purposes 1,400.0   1,200.0                
Aggregate gross unrealized gain for federal tax purposes 1,100.0   1,000.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 21,148.0   21,779.8                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total unfunded commitments 50.0   57.0                
Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2,559.4   2,915.8                
Less: funded commitments (609.4)   (526.2)                
Total unfunded commitments 1,950.0   2,389.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions (15.6)   (13.0)                
Total net adjusted unfunded revolving and delayed draw loan commitments 1,934.4   2,376.6                
Equity investment commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 167.5   119.8                
Less: funded commitments (62.7)   (69.2)                
Total unfunded commitments 104.8   50.6                
Less: commitments substantially at discretion of the Company (50.8)   (50.6)                
Total net adjusted unfunded revolving and delayed draw loan commitments 54.0   0.0                
Senior Direct Lending Program                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4,932.0   4,958.0                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Less: funded commitments (5,160.0)   (5,127.0)                
Total unfunded commitments 217.0   294.0                
Ares Capital Corporation | Senior Direct Lending Program                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Less: funded commitments (1,282.0)   (1,274.0)                
Total unfunded commitments 50.0   68.0                
Ares Capital Corporation | Senior Direct Lending Program | Unfunded commitments                      
Schedule of Investments [Line Items]                      
Other commitment     68.0                
Subordinated certificates of the SDLP                      
Investments Activity And Fair Value Table [Abstract]                      
Interest income 43.0 $ 33.0                  
Capital structuring service fees 1.0 5.0                  
Fair Value $ 1,231.0   $ 1,249.0                
Subordinated certificates of the SDLP | Ares Capital Corporation                      
Schedule of Investments [Line Items]                      
Ownership percentage of outstanding SDLP Certificates 87.50%   87.50% 87.50% 87.50% 87.50% 87.50% 87.50% 87.50% 87.50% 87.50%
Subordinated certificates of the SDLP | Ares Capital Corporation | Minimum                      
Schedule of Investments [Line Items]                      
Ownership percentage of outstanding SDLP Certificates 25.00%   25.00% 25.00% 25.00% 25.00% 25.00% 25.00% 25.00% 25.00% 25.00%
Non-qualifying assets | Investments, at fair value, and other non-qualifying assets | Customer Concentration Risk                      
Schedule of Investments [Line Items]                      
% of Total Assets, non-qualifying assets 25.00%   25.00%                
Non-controlled affiliate                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) $ 3.2   $ 29.5                
Redemptions (cost) 1.3   52.4                
Sales (cost) 0.0   33.3                
Interest income 3.8   12.5                
Capital structuring service fees 0.0   0.1                
Dividend income 0.4   2.0                
Other income 0.0   0.3                
Net realized gains (losses): 0.0   6.1                
Net unrealized gains (losses): 13.9 (1.0) 71.0                
Fair Value 381.4   364.4                
Controlled affiliate                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 337.1   1,994.8                
Redemptions (cost) 233.5   513.1                
Sales (cost) 0.0   0.0                
Interest income 61.9   194.5                
Capital structuring service fees 0.2 4.0 20.0                
Dividend income 63.8 47.0 228.2                
Other income 1.3 2.0 6.0                
Net realized gains (losses): 0.0 19.0 (37.5)                
Net unrealized gains (losses): (31.6) $ (2.0) 1.0                
Fair Value $ 4,195.4   $ 4,119.7                
Royal Bank of Canada                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Counterparty Name [Extensible Enumeration] Royal Bank of Canada     Royal Bank of Canada Royal Bank of Canada Royal Bank of Canada Royal Bank of Canada        
Canadian Imperial Bank of Commerce                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Counterparty Name [Extensible Enumeration] Canadian Imperial Bank of Commerce     Canadian Imperial Bank of Commerce Canadian Imperial Bank of Commerce Canadian Imperial Bank of Commerce Canadian Imperial Bank of Commerce        
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Canadian Imperial Bank of Commerce, Company Settlement Date April 28, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 3.0                    
Derivative Asset, Notional Amount         $ 4            
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 0.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date April 19, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 181.0                    
Derivative Asset, Notional Amount         $ 247            
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ (2.0)                    
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date April 28, 2023, Contract One                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 218.0                    
Derivative Asset, Notional Amount         $ 292            
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 2.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date April 28, 2023, Contract Three                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 0.0                    
Derivative Asset, Notional Amount         $ 1            
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 0.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date April 28, 2023, Contract Two                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 2.0                    
Derivative Asset, Notional Amount         $ 2            
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 0.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date January 18, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration]     Foreign currency forward contract         Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract
Derivative Liability, Notional Amount     $ 178.0                
Derivative Asset, Notional Amount                 $ 242    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset     $ (1.0)                
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date January 27, 2023, Contract One                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration]     Foreign currency forward contract         Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract
Derivative Liability, Notional Amount     $ 195.0                
Derivative Asset, Notional Amount                 $ 264    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset     $ (1.0)                
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date January 27, 2023, Contract Two                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration]     Foreign currency forward contract         Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract
Derivative Liability, Notional Amount     $ 12.0                
Derivative Asset, Notional Amount                 $ 17    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset     $ 0.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: EUR, Royal Bank of Canada, Company Settlement Date April 28, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 240.0                    
Derivative Asset, Notional Amount | €       € 219              
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 2.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: EUR, Royal Bank of Canada, Company Settlement Date January 27, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration]     Foreign currency forward contract         Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract
Derivative Liability, Notional Amount     $ 159.0                
Derivative Asset, Notional Amount | €               € 158      
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset     $ (10.0)                
Open Forward Foreign Currency Contract, Identifier [Axis]: GBP, Royal Bank of Canada, Company Settlement Date April 28, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 159.0                    
Derivative Asset, Notional Amount | £           £ 128          
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 1.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: GBP, Royal Bank of Canada, Company Settlement Date January 27, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration]     Foreign currency forward contract         Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract
Derivative Liability, Notional Amount     $ 145.0                
Derivative Asset, Notional Amount | £                   £ 125  
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset     $ (6.0)                
Open Forward Foreign Currency Contract, Identifier [Axis]: NZD, Royal Bank of Canada, Company Settlement Date April 28, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 37.0                    
Derivative Asset, Notional Amount             $ 58        
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 1.0                    
Open Forward Foreign Currency Contract, Identifier [Axis]: NZD, Royal Bank of Canada, Company Settlement Date January 27, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration]     Foreign currency forward contract         Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract
Derivative Liability, Notional Amount     $ 34.0                
Derivative Asset, Notional Amount                     $ 59
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset     $ (3.0)                
Open Forward Foreign Currency Contract, Identifier [Axis]: USD, Royal Bank of Canada, Company Settlement Date April 28, 2023                      
Derivative Instruments Table [Abstract]                      
Derivative Asset, Type [Extensible Enumeration] Foreign currency forward contract     Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract Foreign currency forward contract        
Derivative Liability, Notional Amount $ 156.0                    
Derivative Asset, Notional Amount 114.0                    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 1.0                    
Investment, Identifier [Axis]: 2U, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.32% [1]   10.16% [2] 11.32% [1] 11.32% [1] 11.32% [1] 11.32% [1] 10.16% [2] 10.16% [2] 10.16% [2] 10.16% [2]
Total first lien senior secured loans $ 5.1 [3],[4],[5]   $ 14.6 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.8 [3],[4],[5]   14.3 [6],[7],[8]                
Investment, Identifier [Axis]: ACAS Equity Holdings Corporation                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   0.0                
Fair Value 0.4   0.4                
Investment, Identifier [Axis]: ACAS Equity Holdings Corporation, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.4 [5]   0.4 [8]                
Investment, Identifier [Axis]: ADF Capital, Inc., ADF Restaurant Group, LLC, and ARG Restaurant Holdings, Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   0.0                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: ADF Capital, Inc., ADF Restaurant Group, LLC, and ARG Restaurant Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 8.7 [4],[9]   8.3 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4],[9]   0.0 [7],[10]                
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 20.5   14.1                
Less: funded commitments (12.6)   (14.1)                
Total unfunded commitments 7.9   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 7.9   $ 0.0                
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon [1] 12.25%     12.25% 12.25% 12.25% 12.25%        
Total first lien senior secured loans [3],[4] $ 7.9                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 6.5                    
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon [1] 12.25%     12.25% 12.25% 12.25% 12.25%        
Total first lien senior secured loans [3],[4] $ 12.6                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 10.5                    
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, First lien senior secured revolving loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.19%         9.19% 9.19% 9.19% 9.19%
Total first lien senior secured loans [6],[7]     $ 9.8                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 9.3                
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     11.25%         11.25% 11.25% 11.25% 11.25%
Total first lien senior secured loans [6],[7]     $ 4.3                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     4.1                
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 131.7 [4],[9]   130.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 52.7 [4],[9]   104.0 [6],[7]                
Investment, Identifier [Axis]: AHR Funding Holdings, Inc. and AHR Parent Holdings, LP, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.6 [4]   10.2 [7]                
Investment, Identifier [Axis]: AHR Funding Holdings, Inc. and AHR Parent Holdings, LP, Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [4]   0.1 [7]                
Investment, Identifier [Axis]: AHR Funding Holdings, Inc. and AHR Parent Holdings, LP, Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 37.8 [4]   $ 35.8 [7]                
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.48% [1]   7.97% [2] 8.48% [1] 8.48% [1] 8.48% [1] 8.48% [1] 7.97% [2] 7.97% [2] 7.97% [2] 7.97% [2]
Total first lien senior secured loans $ 1.0 [3],[4],[11]   $ 1.0 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.0 [3],[4],[11]   0.9 [6],[7],[12]                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 21.7   28.9                
Less: funded commitments (1.9)   (0.4)                
Total unfunded commitments 19.8   28.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 19.8   28.5                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.0 [4]   $ 5.7 [7]                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.13% [1]   10.22% [2] 11.13% [1] 11.13% [1] 11.13% [1] 11.13% [1] 10.22% [2] 10.22% [2] 10.22% [2] 10.22% [2]
Total first lien senior secured loans $ 30.6 [3],[4]   $ 26.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 30.6 [3],[4]   $ 26.8 [6],[7]                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.57%     11.57% 11.57% 11.57% 11.57%        
Total first lien senior secured loans [3],[4] $ 3.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 3.4                    
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.26% [1]   10.61% [2] 11.26% [1] 11.26% [1] 11.26% [1] 11.26% [1] 10.61% [2] 10.61% [2] 10.61% [2] 10.61% [2]
Total first lien senior secured loans $ 1.9 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.9 [3],[4]   0.4 [6],[7]                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 47.4 [3],[4]   45.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 47.4 [3],[4]   45.6 [6],[7]                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 10.7 [3],[4]   10.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.7 [3],[4]   10.3 [6],[7]                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, Second lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 10.4 [3],[4]   10.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.4 [3],[4]   10.0 [6],[7]                
Investment, Identifier [Axis]: AIM Acquisition, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.8   1.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.8   1.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 1.8   1.8                
Investment, Identifier [Axis]: APG Intermediate Holdings Corporation and APG Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.1                
Sales (cost) 0.0   0.0                
Interest income 0.4   1.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 2.1   (3.0)                
Fair Value 23.9   21.8                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.1   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.1   0.1                
Investment, Identifier [Axis]: APG Intermediate Holdings Corporation and APG Holdings, LLC, Class A membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.6 [4]   $ 8.6 [7]                
Investment, Identifier [Axis]: APG Intermediate Holdings Corporation and APG Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.39% [1]   10.36% [2] 10.39% [1] 10.39% [1] 10.39% [1] 10.39% [1] 10.36% [2] 10.36% [2] 10.36% [2] 10.36% [2]
Total first lien senior secured loans $ 13.3 [3],[4]   $ 13.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 13.3 [3],[4]   13.2 [6],[7]                
Investment, Identifier [Axis]: API Commercial Inc., API Military Inc., and API Space Intermediate, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 7.2 [4],[9]   7.3 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.6 [4],[9]   3.6 [7],[10]                
Investment, Identifier [Axis]: AQ Sage Buyer, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.4   6.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 6.4   6.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 6.4   $ 6.4                
Investment, Identifier [Axis]: AQ Sage Buyer, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.38% [1]   10.70% [2] 11.38% [1] 11.38% [1] 11.38% [1] 11.38% [1] 10.70% [2] 10.70% [2] 10.70% [2] 10.70% [2]
Total first lien senior secured loans $ 1.9 [3],[4],[5]   $ 1.9 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [3],[4],[5]   1.8 [6],[7],[8]                
Investment, Identifier [Axis]: AQ Sunshine, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.4   12.4                
Less: funded commitments (3.0)   (1.4)                
Total unfunded commitments 9.4   11.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.4   $ 11.0                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.42% [2] 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 8.9 [3],[4]   $ 8.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.6 [3],[4]   $ 8.8 [6],[7]                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.42% [2] 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 8.5 [3],[4]   $ 8.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.1 [3],[4]   $ 8.3 [6],[7]                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.42% [2] 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 5.6 [3],[4]   $ 5.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.3 [3],[4]   $ 5.5 [6],[7]                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.98% [2] 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [3],[4]   $ 1.0 [6],[7]                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.42% [2] 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.22% [1]   10.42% [2] 11.22% [1] 11.22% [1] 11.22% [1] 11.22% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 3.0 [3],[4],[13]   $ 1.4 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.9 [3],[4],[13]   1.4 [6],[7],[14]                
Investment, Identifier [Axis]: ARES 2007-3R, Subordinated notes                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [5]   0.1 [8]                
Investment, Identifier [Axis]: ASP-r-pac Acquisition CO LLC and ASP-r-pac Holdings LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.2   6.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 6.2   6.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.2   6.2                
Investment, Identifier [Axis]: ASP-r-pac Acquisition CO LLC and ASP-r-pac Holdings LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 16.5 [4]   $ 19.2 [7]                
Investment, Identifier [Axis]: ASP-r-pac Acquisition CO LLC and ASP-r-pac Holdings LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.83% [1]   10.38% [2] 10.83% [1] 10.83% [1] 10.83% [1] 10.83% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: ATI Restoration, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 46.6   83.7                
Less: funded commitments (5.8)   (5.8)                
Total unfunded commitments 40.8   77.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 40.8   $ 77.9                
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.03% [1]   9.36% [2] 10.03% [1] 10.03% [1] 10.03% [1] 10.03% [1] 9.36% [2] 9.36% [2] 9.36% [2] 9.36% [2]
Total first lien senior secured loans $ 45.3 [3],[4]   $ 33.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 45.3 [3],[4]   $ 33.0 [6],[7]                
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.86% [1]   9.65% [2] 9.86% [1] 9.86% [1] 9.86% [1] 9.86% [1] 9.65% [2] 9.65% [2] 9.65% [2] 9.65% [2]
Total first lien senior secured loans $ 32.9 [3],[4]   $ 8.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 32.9 [3],[4]   $ 8.2 [6],[7]                
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.00% [1]   11.50% [2] 12.00% [1] 12.00% [1] 12.00% [1] 12.00% [1] 11.50% [2] 11.50% [2] 11.50% [2] 11.50% [2]
Total first lien senior secured loans $ 4.7 [3],[4],[13]   $ 4.7 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.7 [3],[4],[13]   4.7 [6],[7],[14]                
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 3.7   2.0                
Redemptions (cost) 0.0   3.0                
Sales (cost) 0.0   0.0                
Interest income 2.0   6.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (0.7)   4.6                
Fair Value 73.9   70.2                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.1   7.1                
Less: funded commitments (6.9)   (3.2)                
Total unfunded commitments 0.2   3.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.2   3.9                
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.2 [4]   $ 14.9 [7]                
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 14.16% [1]   13.73% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.73% [2] 13.73% [2] 13.73% [2] 13.73% [2]
Total first lien senior secured loans $ 52.8 [3],[4]   $ 52.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 52.8 [3],[4]   $ 52.1 [6],[7]                
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, First lien senior secured revolving loan 1                      
Schedule of Investments [Line Items]                      
Coupon 14.16% [1]   15.50% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 15.50% [2] 15.50% [2] 15.50% [2] 15.50% [2]
Total first lien senior secured loans $ 6.9 [3],[4]   $ 2.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.9 [3],[4]   $ 2.2 [6],[7]                
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     13.77%         13.77% 13.77% 13.77% 13.77%
Total first lien senior secured loans [6],[7]     $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     1.0                
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     0.1                
Less: funded commitments     0.0                
Total unfunded commitments     0.1                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     0.1                
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd., A ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.7 [4],[5]   $ 6.5 [7],[8]                
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     14.54%         14.54% 14.54% 14.54% 14.54%
Total first lien senior secured loans [6],[7],[8]     $ 61.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7],[8]     59.8                
Investment, Identifier [Axis]: Accommodations Plus Technologies LLC and Accommodations Plus Technologies Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1                
Less: funded commitments (4.1)   (4.1)                
Total unfunded commitments 0.0   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: Accommodations Plus Technologies LLC and Accommodations Plus Technologies Holdings LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.5   $ 6.6                
Investment, Identifier [Axis]: Accommodations Plus Technologies LLC and Accommodations Plus Technologies Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.80% [1]   12.48% [2] 12.80% [1] 12.80% [1] 12.80% [1] 12.80% [1] 12.48% [2] 12.48% [2] 12.48% [2] 12.48% [2]
Total first lien senior secured loans $ 4.1 [3],[4]   $ 4.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.1 [3],[4]   $ 4.1 [6],[7]                
Investment, Identifier [Axis]: Acrisure, LLC and Acrisure Finance, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     700.00%         700.00% 700.00% 700.00% 700.00%
Total first lien senior secured loans [7],[12]     $ 0.5                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7],[12]     0.5                
Investment, Identifier [Axis]: Advarra Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.4   0.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.4   0.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.4   $ 0.4                
Investment, Identifier [Axis]: Advarra Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.56% [1]   10.15% [2] 10.56% [1] 10.56% [1] 10.56% [1] 10.56% [1] 10.15% [2] 10.15% [2] 10.15% [2] 10.15% [2]
Total first lien senior secured loans $ 4.1 [3],[4]   $ 4.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.9 [3],[4]   $ 3.9 [6],[7]                
Investment, Identifier [Axis]: Aero Operating LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.74% [1]   13.24% [2] 13.74% [1] 13.74% [1] 13.74% [1] 13.74% [1] 13.24% [2] 13.24% [2] 13.24% [2] 13.24% [2]
Total first lien senior secured loans $ 36.1 [3],[4]   $ 36.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.9 [3],[4]   $ 35.1 [6],[7]                
Investment, Identifier [Axis]: Aero Operating LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.74% [1]   13.24% [2] 13.74% [1] 13.74% [1] 13.74% [1] 13.74% [1] 13.24% [2] 13.24% [2] 13.24% [2] 13.24% [2]
Total first lien senior secured loans $ 1.1 [3],[4]   $ 1.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.1 [3],[4]   1.1 [6],[7]                
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 45.6   45.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 45.6   45.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 45.6   $ 45.6                
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.64% [1]   10.64% [2] 10.64% [1] 10.64% [1] 10.64% [1] 10.64% [1] 10.64% [2] 10.64% [2] 10.64% [2] 10.64% [2]
Total first lien senior secured loans $ 120.3 [3],[4]   $ 120.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 114.2 [3],[4]   $ 115.7 [6],[7]                
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.45% [1]   10.45% [2] 10.45% [1] 10.45% [1] 10.45% [1] 10.45% [1] 10.45% [2] 10.45% [2] 10.45% [2] 10.45% [2]
Total first lien senior secured loans $ 63.2 [3],[4]   $ 63.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 60.0 [3],[4]   60.8 [6],[7]                
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0                    
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [6],[7]     56.8                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 54.4                
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, Senior subordinated loan 1                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [4] 32.7                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 31.1                    
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [3],[4] 27.3                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 25.9                    
Investment, Identifier [Axis]: Aimbridge Acquisition Co., Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.16% [1]   11.62% [2] 12.16% [1] 12.16% [1] 12.16% [1] 12.16% [1] 11.62% [2] 11.62% [2] 11.62% [2] 11.62% [2]
Total first lien senior secured loans $ 22.5 [4]   $ 22.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 21.8 [4]   $ 21.8 [7]                
Investment, Identifier [Axis]: Alcami Corporation and ACM Holdings I, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.42% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.42% [2] 11.42% [2] 11.42% [2] 11.42% [2]
Total first lien senior secured loans $ 9.5 [4]   $ 9.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.1 [4]   9.0 [6],[7]                
Investment, Identifier [Axis]: Alcami Corporation and ACM Holdings I, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 19.9 [4]   19.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.9 [4]   19.5 [7]                
Investment, Identifier [Axis]: Alcami Corporation and ACM Note Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.6   6.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.6   6.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.6   $ 6.6                
Investment, Identifier [Axis]: Alera Group Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.91%     10.91% 10.91% 10.91% 10.91%        
Total first lien senior secured loans [3],[4] $ 60.5                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 59.3                    
Investment, Identifier [Axis]: Alera Group, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.42%         10.42% 10.42% 10.42% 10.42%
Total first lien senior secured loans [6],[7]     $ 60.6                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     58.8                
Investment, Identifier [Axis]: American Residential Services L.L.C. and Aragorn Parent Holdings LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5                
Less: funded commitments (2.1)   (0.9)                
Total unfunded commitments 2.4   3.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.4   $ 3.6                
Investment, Identifier [Axis]: American Residential Services L.L.C. and Aragorn Parent Holdings LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.75% [1]   7.14% [2] 9.75% [1] 9.75% [1] 9.75% [1] 9.75% [1] 7.14% [2] 7.14% [2] 7.14% [2] 7.14% [2]
Total first lien senior secured loans $ 1.1 [3],[4]   $ 0.6 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.1 [3],[4]   $ 0.6 [7]                
Investment, Identifier [Axis]: American Residential Services L.L.C. and Aragorn Parent Holdings LP, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.56% [1]   9.25% [2] 7.56% [1] 7.56% [1] 7.56% [1] 7.56% [1] 9.25% [2] 9.25% [2] 9.25% [2] 9.25% [2]
Total first lien senior secured loans $ 1.0 [4]   $ 0.3 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [4]   $ 0.3 [7]                
Investment, Identifier [Axis]: American Residential Services L.L.C. and Aragorn Parent Holdings LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.66% [1]   13.23% [2] 13.66% [1] 13.66% [1] 13.66% [1] 13.66% [1] 13.23% [2] 13.23% [2] 13.23% [2] 13.23% [2]
Total first lien senior secured loans $ 56.4 [3],[4]   $ 56.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 56.4 [3],[4]   56.4 [6],[7]                
Investment, Identifier [Axis]: American Residential Services L.L.C. and Aragorn Parent Holdings LP, Series A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.6 [4]   6.5 [7]                
Investment, Identifier [Axis]: American Seafoods Group LLC and American Seafoods Partners LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.3 [4]   0.3 [7]                
Investment, Identifier [Axis]: American Seafoods Group LLC and American Seafoods Partners LLC, Warrant to purchase up to 7,422,078 Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 25.3 [4]   $ 28.0 [7]                
Investment, Identifier [Axis]: Amryt Pharmaceuticals, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.49% [1]   10.46% [2] 11.49% [1] 11.49% [1] 11.49% [1] 11.49% [1] 10.46% [2] 10.46% [2] 10.46% [2] 10.46% [2]
Total first lien senior secured loans $ 12.7 [3],[4],[5]   $ 12.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 13.4 [3],[4],[5]   $ 12.7 [6],[7],[8]                
Investment, Identifier [Axis]: Amynta Agency Borrower Inc. and Amynta Warranty Borrower Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.89% [1]   9.58% [2] 9.89% [1] 9.89% [1] 9.89% [1] 9.89% [1] 9.58% [2] 9.58% [2] 9.58% [2] 9.58% [2]
Total first lien senior secured loans $ 1.0 [4]   $ 14.6 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.0 [4]   $ 14.0 [7]                
Investment, Identifier [Axis]: Amynta Agency Borrower Inc. and Amynta Warranty Borrower Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.88%         8.88% 8.88% 8.88% 8.88%
Total first lien senior secured loans [7]     $ 2.3                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     2.2                
Investment, Identifier [Axis]: Anaplan, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.4   1.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.4   1.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.4   $ 1.4                
Investment, Identifier [Axis]: Anaplan, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.31% [1]   10.82% [2] 11.31% [1] 11.31% [1] 11.31% [1] 11.31% [1] 10.82% [2] 10.82% [2] 10.82% [2] 10.82% [2]
Total first lien senior secured loans $ 1.8 [3],[4]   $ 1.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.7 [3],[4]   1.7 [6],[7]                
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.4   3.4                
Less: funded commitments (0.1)   0.0                
Total unfunded commitments 3.3   3.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.3   $ 3.4                
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.58% [1]   7.52% [2] 7.58% [1] 7.58% [1] 7.58% [1] 7.58% [1] 7.52% [2] 7.52% [2] 7.52% [2] 7.52% [2]
Total first lien senior secured loans $ 4.4 [3],[4]   $ 4.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.4 [3],[4]   $ 4.4 [7]                
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.19% [1]   9.11% [2] 10.19% [1] 10.19% [1] 10.19% [1] 10.19% [1] 9.11% [2] 9.11% [2] 9.11% [2] 9.11% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [3],[4]   1.0 [6],[7]                
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.19%     10.19% 10.19% 10.19% 10.19%        
Total first lien senior secured loans [4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 0.1                    
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua, Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 7.7 [4],[5]   8.3 [7],[8]                
Investment, Identifier [Axis]: Apex Clean Energy TopCo, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   18.1                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   53.4                
Fair Value 150.6   150.6                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 36.2                    
Less: funded commitments 0.0                    
Total unfunded commitments 36.2                    
Less: commitments substantially at discretion of the Company 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 36.2                    
Investment, Identifier [Axis]: Apex Clean Energy TopCo, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 150.6   150.6                
Investment, Identifier [Axis]: Apex Service Partners, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.5                    
Less: funded commitments 0.0                    
Total unfunded commitments 8.5                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 8.5                    
Investment, Identifier [Axis]: Apex Service Partners, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.26%     10.26% 10.26% 10.26% 10.26%        
Total first lien senior secured loans [3],[4] $ 24.7                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 23.2                    
Investment, Identifier [Axis]: Applied Technical Services, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.7   3.8                
Less: funded commitments (2.6)   (1.1)                
Total unfunded commitments 1.1   2.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.1   $ 2.7                
Investment, Identifier [Axis]: Applied Technical Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.48% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.9 [3],[4]   $ 0.8 [6],[7]                
Investment, Identifier [Axis]: Applied Technical Services, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.75% [1]   12.25% [2] 12.75% [1] 12.75% [1] 12.75% [1] 12.75% [1] 12.25% [2] 12.25% [2] 12.25% [2] 12.25% [2]
Total first lien senior secured loans $ 2.6 [3]   $ 1.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.6 [3]   1.1 [6],[7]                
Investment, Identifier [Axis]: Appriss Health, LLC and Appriss Health Intermediate Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.1   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.1   $ 0.1                
Investment, Identifier [Axis]: Appriss Health, LLC and Appriss Health Intermediate Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.96% [1]   11.54% [2] 11.96% [1] 11.96% [1] 11.96% [1] 11.96% [1] 11.54% [2] 11.54% [2] 11.54% [2] 11.54% [2]
Total first lien senior secured loans $ 5.6 [3],[4]   $ 5.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.6 [3],[4]   5.7 [6],[7]                
Investment, Identifier [Axis]: Appriss Health, LLC and Appriss Health Intermediate Holdings, Inc., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 36.2 [4]   35.6 [7]                
Investment, Identifier [Axis]: Apptio, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.2   4.2                
Less: funded commitments (3.8)   (2.5)                
Total unfunded commitments 0.4   1.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.4   $ 1.7                
Investment, Identifier [Axis]: Apptio, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.81% [1]   9.94% [2] 9.81% [1] 9.81% [1] 9.81% [1] 9.81% [1] 9.94% [2] 9.94% [2] 9.94% [2] 9.94% [2]
Total first lien senior secured loans $ 15.1 [3],[4]   $ 15.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.1 [3],[4]   $ 15.1 [6],[7]                
Investment, Identifier [Axis]: Apptio, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   9.93% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 9.93% [2] 9.93% [2] 9.93% [2] 9.93% [2]
Total first lien senior secured loans $ 3.8 [3],[4]   $ 2.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.8 [3],[4]   $ 2.5 [6],[7]                
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.6                    
Less: funded commitments 0.0                    
Total unfunded commitments 15.6                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 15.6                    
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.25% [1]   8.81% [2] 11.25% [1] 11.25% [1] 11.25% [1] 11.25% [1] 8.81% [2] 8.81% [2] 8.81% [2] 8.81% [2]
Total first lien senior secured loans $ 90.0 [3],[4],[5]   $ 90.0 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 89.1 [3],[4],[5]   $ 89.1 [6],[7],[8]                
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.57% [1]   8.19% [2] 9.57% [1] 9.57% [1] 9.57% [1] 9.57% [1] 8.19% [2] 8.19% [2] 8.19% [2] 8.19% [2]
Total first lien senior secured loans $ 67.8 [3],[4],[5]   $ 66.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 67.8 [3],[4],[5]   $ 66.8 [6],[7],[8]                
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.74% [1]   8.19% [2] 11.74% [1] 11.74% [1] 11.74% [1] 11.74% [1] 8.19% [2] 8.19% [2] 8.19% [2] 8.19% [2]
Total first lien senior secured loans $ 76.6 [3],[4],[5]   $ 75.0 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 76.6 [3],[4],[5]   $ 75.0 [6],[7],[8]                
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.22% [1]   8.00% [2] 12.22% [1] 12.22% [1] 12.22% [1] 12.22% [1] 8.00% [2] 8.00% [2] 8.00% [2] 8.00% [2]
Total first lien senior secured loans $ 15.6 [3],[4],[5]   $ 7.0 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.6 [3],[4],[5]   7.0 [6],[7],[8]                
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.07%     10.07% 10.07% 10.07% 10.07%        
Total first lien senior secured loans [3],[4],[5] $ 7.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[5] 7.1                    
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 1.4 [4],[5],[13]   1.4 [7],[8],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.3 [4],[5],[13]   1.4 [7],[8],[12]                
Investment, Identifier [Axis]: Argenbright Holdings V, LLC and Amberstone Security Group Limited                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.5   2.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.5   2.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.5   $ 2.5                
Investment, Identifier [Axis]: Argenbright Holdings V, LLC and Amberstone Security Group Limited, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.09% [1]   11.49% [2] 12.09% [1] 12.09% [1] 12.09% [1] 12.09% [1] 11.49% [2] 11.49% [2] 11.49% [2] 11.49% [2]
Total first lien senior secured loans $ 6.0 [3],[4],[5]   $ 20.9 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.0 [3],[4],[5]   $ 20.7 [6],[7],[8]                
Investment, Identifier [Axis]: Argenbright Holdings V, LLC and Amberstone Security Group Limited, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.08% [1]   11.53% [2] 12.08% [1] 12.08% [1] 12.08% [1] 12.08% [1] 11.53% [2] 11.53% [2] 11.53% [2] 11.53% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 5.9 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4],[5]   5.8 [6],[7],[8]                
Investment, Identifier [Axis]: Arrowhead Holdco Company and Arrowhead GS Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.4 [4]   $ 6.4 [7]                
Investment, Identifier [Axis]: Arrowhead Holdco Company and Arrowhead GS Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.33% [1]   8.68% [2] 9.33% [1] 9.33% [1] 9.33% [1] 9.33% [1] 8.68% [2] 8.68% [2] 8.68% [2] 8.68% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[13]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4],[13]   0.1 [6],[7]                
Investment, Identifier [Axis]: AthenaHealth Group Inc., Minerva Holdco, Inc. and BCPE Co-Invest (A), LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.0   9.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 9.0   9.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 9.0   9.0                
Investment, Identifier [Axis]: AthenaHealth Group Inc., Minerva Holdco, Inc. and BCPE Co-Invest (A), LP 1                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.2                    
Less: funded commitments 0.0                    
Total unfunded commitments 1.2                    
Less: commitments substantially at discretion of the Company 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 1.2                    
Investment, Identifier [Axis]: AthenaHealth Group Inc., Minerva Holdco, Inc. and BCPE Co-Invest (A), LP, Class A Units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 9.5                    
Investment, Identifier [Axis]: AthenaHealth Group Inc., Minerva Holdco, Inc. and BCPE Co-Invest (A), LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     9.5                
Investment, Identifier [Axis]: AthenaHealth Group Inc., Minerva Holdco, Inc. and BCPE Co-Invest (A), LP, Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 201.6 [4]   198.5 [7]                
Investment, Identifier [Axis]: Athyrium Buffalo LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.9   15.5                
Less: funded commitments 0.0   (7.6)                
Total unfunded commitments 7.9   7.9                
Less: commitments substantially at discretion of the Company (7.9)   (7.9)                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: Athyrium Buffalo LP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 7.5 [4],[5]   7.5 [7],[8]                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.8   0.8                
Less: funded commitments (0.2)   (0.2)                
Total unfunded commitments 0.6   0.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.6   $ 0.6                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.74% [1]   10.48% [2] 10.74% [1] 10.74% [1] 10.74% [1] 10.74% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.74% [1]   10.48% [2] 10.74% [1] 10.74% [1] 10.74% [1] 10.74% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.74% [1]   10.48% [2] 10.74% [1] 10.74% [1] 10.74% [1] 10.74% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.74% [1]   10.48% [2] 10.74% [1] 10.74% [1] 10.74% [1] 10.74% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.53% [1]   10.10% [2] 10.53% [1] 10.53% [1] 10.53% [1] 10.53% [1] 10.10% [2] 10.10% [2] 10.10% [2] 10.10% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: Auctane, Inc. (fka Stamps.com Inc.), First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.59%     10.59% 10.59% 10.59% 10.59%        
Total first lien senior secured loans [3],[4] $ 146.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 140.5                    
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4]   $ 0.0                
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.43% [1]   10.93% [2] 11.43% [1] 11.43% [1] 11.43% [1] 11.43% [1] 10.93% [2] 10.93% [2] 10.93% [2] 10.93% [2]
Total first lien senior secured loans $ 5.3 [3],[4]   $ 5.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.3 [3],[4]   $ 5.3 [6],[7]                
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   9.73% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 9.73% [2] 9.73% [2] 9.73% [2] 9.73% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.9 [4]   5.2 [7]                
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, Preferred units 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 1.0                    
Investment, Identifier [Axis]: Avalara, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.7   2.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.7   2.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.7   $ 2.7                
Investment, Identifier [Axis]: Avalara, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.15% [1]   11.83% [2] 12.15% [1] 12.15% [1] 12.15% [1] 12.15% [1] 11.83% [2] 11.83% [2] 11.83% [2] 11.83% [2]
Total first lien senior secured loans $ 72.2 [3],[4]   $ 72.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 70.4 [3],[4]   70.4 [6],[7]                
Investment, Identifier [Axis]: Aventine Intermediate LLC & Aventine Holdings II LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2   0.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.2   0.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.2   $ 0.2                
Investment, Identifier [Axis]: Aventine Intermediate LLC & Aventine Holdings II LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 10.84% [1]   10.38% [2] 10.84% [1] 10.84% [1] 10.84% [1] 10.84% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 9.5 [3],[4]   $ 9.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.5 [3],[4]   9.3 [6],[7]                
Investment, Identifier [Axis]: Aventine Intermediate LLC & Aventine Holdings II LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 39.4 [4]   39.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 36.7 [4]   $ 36.2 [7]                
Investment, Identifier [Axis]: Aventiv Technologies, LLC and Securus Technologies Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.66% [1]   9.23% [2] 9.66% [1] 9.66% [1] 9.66% [1] 9.66% [1] 9.23% [2] 9.23% [2] 9.23% [2] 9.23% [2]
Total first lien senior secured loans $ 9.1 [3],[4],[11]   $ 9.1 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.5 [3],[4],[11]   $ 6.8 [6],[7],[12]                
Investment, Identifier [Axis]: Aventiv Technologies, LLC and Securus Technologies Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.08% [1]   12.66% [2] 13.08% [1] 13.08% [1] 13.08% [1] 13.08% [1] 12.66% [2] 12.66% [2] 12.66% [2] 12.66% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: Avetta, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.2   4.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.2   4.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.2   $ 4.2                
Investment, Identifier [Axis]: Avetta, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.58% [1]   10.16% [2] 10.58% [1] 10.58% [1] 10.58% [1] 10.58% [1] 10.16% [2] 10.16% [2] 10.16% [2] 10.16% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: AxiomSL Group, Inc. and Calypso Group, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.9   3.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.9   $ 3.9                
Investment, Identifier [Axis]: AxiomSL Group, Inc. and Calypso Group, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 21.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   21.2 [6],[7]                
Investment, Identifier [Axis]: Axiomatic, LLC, Class A-1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.4   5.3                
Investment, Identifier [Axis]: BAART Programs, Inc., MedMark Services, Inc., and Canadian Addiction Treatment Centres LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     2.0                
Less: funded commitments     0.0                
Total unfunded commitments     2.0                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 2.0                
Investment, Identifier [Axis]: BAART Programs, Inc., MedMark Services, Inc., and Canadian Addiction Treatment Centres LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.16% [1]   9.73% [2] 10.16% [1] 10.16% [1] 10.16% [1] 10.16% [1] 9.73% [2] 9.73% [2] 9.73% [2] 9.73% [2]
Total first lien senior secured loans $ 6.0 [3],[4]   $ 6.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.9 [3],[4]   5.9 [6],[7]                
Investment, Identifier [Axis]: BCC Blueprint Holdings I, LLC and BCC Blueprint Investments, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.3 [4]   $ 3.9 [7]                
Investment, Identifier [Axis]: BCC Blueprint Holdings I, LLC and BCC Blueprint Investments, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.12% [1]   11.02% [2] 11.12% [1] 11.12% [1] 11.12% [1] 11.12% [1] 11.02% [2] 11.02% [2] 11.02% [2] 11.02% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: BCC Blueprint Holdings I, LLC and BCC Blueprint Investments, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 5.1 [4]   5.0 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.1 [4]   4.9 [7]                
Investment, Identifier [Axis]: BH-Sharp Holdings LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.9 [4]   $ 2.3 [7]                
Investment, Identifier [Axis]: Badger Sportswear Acquisition, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.89% [1]   13.57% [2] 13.89% [1] 13.89% [1] 13.89% [1] 13.89% [1] 13.57% [2] 13.57% [2] 13.57% [2] 13.57% [2]
Total first lien senior secured loans $ 56.8 [3],[4]   $ 56.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 56.8 [3],[4]   56.8 [6],[7]                
Investment, Identifier [Axis]: Balrog Acquisition, Inc., Balrog Topco, Inc. and Balrog Parent, L.P., Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.1 [4]   $ 10.5 [7]                
Investment, Identifier [Axis]: Balrog Acquisition, Inc., Balrog Topco, Inc. and Balrog Parent, L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.95% [1]   11.73% [2] 11.95% [1] 11.95% [1] 11.95% [1] 11.95% [1] 11.73% [2] 11.73% [2] 11.73% [2] 11.73% [2]
Total first lien senior secured loans $ 29.5 [3],[4]   $ 29.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 29.5 [3],[4]   29.5 [6],[7]                
Investment, Identifier [Axis]: Balrog Acquisition, Inc., Balrog Topco, Inc. and Balrog Parent, L.P., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 26.1 [4]   25.4 [7]                
Investment, Identifier [Axis]: Bambino Group Holdings, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.8 [4]   $ 0.9 [7]                
Investment, Identifier [Axis]: Bamboo Purchaser, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.05% [1]   10.73% [2] 12.05% [1] 12.05% [1] 12.05% [1] 12.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 17.9 [3],[4]   $ 17.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 17.0 [3],[4]   17.4 [6],[7]                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.6   8.0                
Less: funded commitments (1.0)   (0.9)                
Total unfunded commitments 11.6   7.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 11.6   $ 7.1                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.23% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 20.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [3],[4]   $ 20.3 [6],[7]                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.23% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 1.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 1.0 [6],[7]                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.32% [1]   10.88% [2] 10.32% [1] 10.32% [1] 10.32% [1] 10.32% [1] 10.88% [2] 10.88% [2] 10.88% [2] 10.88% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 0.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.0 [3],[4]   0.9 [6],[7]                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 7.8 [4]   5.4 [7]                
Investment, Identifier [Axis]: Beacon Pointe Harmony, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   5.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.5   5.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.5   $ 5.5                
Investment, Identifier [Axis]: Beacon Pointe Harmony, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [1]   9.39% [2] 9.92% [1] 9.92% [1] 9.92% [1] 9.92% [1] 9.39% [2] 9.39% [2] 9.39% [2] 9.39% [2]
Total first lien senior secured loans $ 18.8 [3],[4],[5]   $ 17.9 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 18.6 [3],[4],[5]   17.7 [6],[7],[8]                
Investment, Identifier [Axis]: Belfor Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 25.0   25.0                
Less: funded commitments (21.4)   (17.0)                
Total unfunded commitments 3.6   8.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.6   $ 8.0                
Investment, Identifier [Axis]: Belfor Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.38% [1]   7.25% [2] 8.38% [1] 8.38% [1] 8.38% [1] 8.38% [1] 7.25% [2] 7.25% [2] 7.25% [2] 7.25% [2]
Total first lien senior secured loans $ 16.6 [4],[13]   $ 11.6 [7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 17.1 [4],[13]   $ 12.1 [7],[14]                
Investment, Identifier [Axis]: Belfor Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.25%         10.25% 10.25% 10.25% 10.25%
Total first lien senior secured loans [7],[14]     $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7],[14]     1.4                
Investment, Identifier [Axis]: Benecon Midco II LLC and Locutus Holdco LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.5   4.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 4.5   4.5                
Investment, Identifier [Axis]: Benecon Midco II LLC and Locutus Holdco LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.5   22.1                
Investment, Identifier [Axis]: Benefytt Technologies, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.9   0.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions (0.9)   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   $ 0.9                
Investment, Identifier [Axis]: Benefytt Technologies, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     13.16%         13.16% 13.16% 13.16% 13.16%
Total first lien senior secured loans 29.7 [4],[9]   $ 29.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 14.8 [4],[9]   23.9 [6],[7]                
Investment, Identifier [Axis]: Berner Food & Beverage, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.7   1.7                
Less: funded commitments (0.9)   (0.5)                
Total unfunded commitments 0.8   1.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.8   $ 1.2                
Investment, Identifier [Axis]: Berner Food & Beverage, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.33% [1]   12.00% [2] 10.33% [1] 10.33% [1] 10.33% [1] 10.33% [1] 12.00% [2] 12.00% [2] 12.00% [2] 12.00% [2]
Total first lien senior secured loans $ 0.5 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.5 [3],[4]   $ 0.4 [6],[7]                
Investment, Identifier [Axis]: Berner Food & Beverage, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.50% [1]   9.91% [2] 12.50% [1] 12.50% [1] 12.50% [1] 12.50% [1] 9.91% [2] 9.91% [2] 9.91% [2] 9.91% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.4 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Blue Wolf Capital Fund II, L.P.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   (0.2)                
Fair Value 0.1   0.1                
Investment, Identifier [Axis]: Blue Wolf Capital Fund II, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [5],[11]   0.1 [8],[12]                
Investment, Identifier [Axis]: BlueHalo Financing Holdings, LLC, BlueHalo Global Holdings, LLC, and BlueHalo, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.0   3.0                
Less: funded commitments (0.4)   (2.8)                
Total unfunded commitments 2.6   0.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.6   $ 0.2                
Investment, Identifier [Axis]: BlueHalo Financing Holdings, LLC, BlueHalo Global Holdings, LLC, and BlueHalo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   10.70% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 10.70% [2] 10.70% [2] 10.70% [2] 10.70% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [3],[4]   $ 1.0 [6],[7]                
Investment, Identifier [Axis]: BlueHalo Financing Holdings, LLC, BlueHalo Global Holdings, LLC, and BlueHalo, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.62% [1]   10.72% [2] 11.62% [1] 11.62% [1] 11.62% [1] 11.62% [1] 10.72% [2] 10.72% [2] 10.72% [2] 10.72% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 2.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.4 [3],[4]   2.7 [6],[7]                
Investment, Identifier [Axis]: Borrower R365 Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.3   2.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.3   $ 2.9                
Investment, Identifier [Axis]: Borrower R365 Holdings LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon 8.66% [1]   8.23% [2] 8.66% [1] 8.66% [1] 8.66% [1] 8.66% [1] 8.23% [2] 8.23% [2] 8.23% [2] 8.23% [2]
Total first lien senior secured loans $ 16.0 [3],[4]   $ 15.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 16.0 [3],[4]   $ 15.9 [6],[7]                
Investment, Identifier [Axis]: Borrower R365 Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon 8.66% [1]   8.23% [2] 8.66% [1] 8.66% [1] 8.66% [1] 8.66% [1] 8.23% [2] 8.23% [2] 8.23% [2] 8.23% [2]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 1.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.0 [3],[4]   1.4 [6],[7]                
Investment, Identifier [Axis]: Bottomline Technologies, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     2.3                
Less: funded commitments     0.0                
Total unfunded commitments     2.3                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 2.3                
Investment, Identifier [Axis]: Bottomline Technologies, Inc. and Legal Spend Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3                    
Less: funded commitments 0.0                    
Total unfunded commitments 2.3                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.3                    
Investment, Identifier [Axis]: Bottomline Technologies, Inc. and Legal Spend Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.26%     10.26% 10.26% 10.26% 10.26%        
Total first lien senior secured loans [3],[4] $ 18.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 17.6                    
Investment, Identifier [Axis]: Bottomline Technologies, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.82%         9.82% 9.82% 9.82% 9.82%
Total first lien senior secured loans [6],[7]     $ 18.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     17.6                
Investment, Identifier [Axis]: Bowhunter Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 1.6   3.3                
Redemptions (cost) 0.9   5.7                
Sales (cost) 0.0   9.8                
Interest income 0.9   3.4                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.2                
Net realized gains (losses): 0.0   (0.2)                
Net unrealized gains (losses): (0.3)   3.5                
Fair Value 39.4   39.1                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.4   4.4                
Less: funded commitments (0.7)   0.0                
Total unfunded commitments 3.7   4.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.7   4.4                
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P., Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.5 [4]   $ 10.8 [7]                
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.00% [1]   11.58% [2] 12.00% [1] 12.00% [1] 12.00% [1] 12.00% [1] 11.58% [2] 11.58% [2] 11.58% [2] 11.58% [2]
Total first lien senior secured loans $ 0.7 [3],[4]   $ 28.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.7 [3],[4]   $ 28.3 [6],[7]                
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.00%     12.00% 12.00% 12.00% 12.00%        
Total first lien senior secured loans [3],[4] $ 28.8                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 28.2                    
Investment, Identifier [Axis]: Burgess Point Purchaser Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.16% [1]   9.67% [2] 10.16% [1] 10.16% [1] 10.16% [1] 10.16% [1] 9.67% [2] 9.67% [2] 9.67% [2] 9.67% [2]
Total first lien senior secured loans $ 4.7 [3],[4],[11]   $ 4.8 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.4 [3],[4],[11]   4.3 [6],[7],[12]                
Investment, Identifier [Axis]: Businessolver.com, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.6   3.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.6   3.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.6   $ 3.6                
Investment, Identifier [Axis]: Businessolver.com, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.06% [1]   9.67% [2] 10.06% [1] 10.06% [1] 10.06% [1] 10.06% [1] 9.67% [2] 9.67% [2] 9.67% [2] 9.67% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 14.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.4 [3],[4]   14.5 [6],[7]                
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.0   12.0                
Less: funded commitments (5.5)   (3.7)                
Total unfunded commitments 6.5   8.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 6.5   $ 8.3                
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.33% [1]   9.91% [2] 10.33% [1] 10.33% [1] 10.33% [1] 10.33% [1] 9.91% [2] 9.91% [2] 9.91% [2] 9.91% [2]
Total first lien senior secured loans $ 33.5 [4],[11]   $ 33.6 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 22.0 [4],[11]   26.2 [7],[12]                
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.24%     10.24% 10.24% 10.24% 10.24%        
Total first lien senior secured loans $ 4.2 [4],[11],[13]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.7 [4],[11],[13]   0.0 [15]                
Investment, Identifier [Axis]: CDI Holdings III Corp. and CDI Holdings I Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.9   0.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.9   0.9                
Investment, Identifier [Axis]: CDI Holdings III Corp. and CDI Holdings I Corp., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.2 [4]   $ 4.4 [7]                
Investment, Identifier [Axis]: CDI Holdings III Corp. and CDI Holdings I Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 3.8 [3],[4]   $ 3.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.7 [3],[4]   3.6 [6],[7]                
Investment, Identifier [Axis]: CHG PPC Parent LLC & PPC CHG Blocker LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.9 [4]   $ 2.9 [7]                
Investment, Identifier [Axis]: CHG PPC Parent LLC & PPC CHG Blocker LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   11.13% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 94.6 [3],[4]   $ 94.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 91.8 [3],[4]   89.9 [6],[7]                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.2   10.2                
Less: funded commitments (0.8)   (0.4)                
Total unfunded commitments 9.4   9.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 9.4   9.8                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.4 [4]   $ 4.6 [7]                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.80% [1]   9.52% [2] 9.80% [1] 9.80% [1] 9.80% [1] 9.80% [1] 9.52% [2] 9.52% [2] 9.52% [2] 9.52% [2]
Total first lien senior secured loans $ 25.5 [3],[4]   $ 21.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 25.0 [3],[4]   $ 21.4 [6],[7]                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.40%         9.40% 9.40% 9.40% 9.40%
Total first lien senior secured loans [6],[7]     $ 3.8                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 3.7                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.05% [1]   9.47% [2] 10.05% [1] 10.05% [1] 10.05% [1] 10.05% [1] 9.47% [2] 9.47% [2] 9.47% [2] 9.47% [2]
Total first lien senior secured loans $ 0.8   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.8   0.4 [6],[7]                
Investment, Identifier [Axis]: CMW Parent LLC (fka Black Arrow, Inc.), Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: CREST Exeter Street Solar 2004-1, Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [5]   0.0 [8]                
Investment, Identifier [Axis]: CST Holding Company                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9   1.9                
Less: funded commitments (0.2)   (0.2)                
Total unfunded commitments 1.7   1.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.7   $ 1.7                
Investment, Identifier [Axis]: CST Holding Company, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   10.97% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 10.97% [2] 10.97% [2] 10.97% [2] 10.97% [2]
Total first lien senior secured loans $ 11.7 [3],[4]   $ 11.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.4 [3],[4]   $ 11.4 [6],[7]                
Investment, Identifier [Axis]: CST Holding Company, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   10.97% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 10.97% [2] 10.97% [2] 10.97% [2] 10.97% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.6   25.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 22.6   25.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 22.6   25.8                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 24.6 [4]   $ 22.7 [7]                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.24% [1]   11.13% [2] 11.24% [1] 11.24% [1] 11.24% [1] 11.24% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 40.4 [3],[4]   $ 49.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 40.4 [3],[4]   $ 49.0 [6],[7]                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.24% [1]   11.13% [2] 11.24% [1] 11.24% [1] 11.24% [1] 11.24% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 38.8 [3],[4]   $ 38.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 38.8 [3],[4]   $ 38.5 [6],[7]                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.08% [1]   10.98% [2] 11.08% [1] 11.08% [1] 11.08% [1] 11.08% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 4.9 [3],[4]   $ 1.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.9 [3],[4]   $ 1.6 [6],[7]                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.24% [1]   11.13% [2] 11.24% [1] 11.24% [1] 11.24% [1] 11.24% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.4   15.3                
Less: funded commitments (15.4)   (14.8)                
Total unfunded commitments 0.0   0.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 0.5                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 13.33% [1]   12.92% [2] 13.33% [1] 13.33% [1] 13.33% [1] 13.33% [1] 12.92% [2] 12.92% [2] 12.92% [2] 12.92% [2]
Total first lien senior secured loans $ 31.0 [3],[4]   $ 31.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 31.0 [3],[4]   $ 30.5 [6],[7]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon 13.33% [1]   12.92% [2] 13.33% [1] 13.33% [1] 13.33% [1] 13.33% [1] 12.92% [2] 12.92% [2] 12.92% [2] 12.92% [2]
Total first lien senior secured loans $ 11.8 [3],[4]   $ 11.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.8 [3],[4]   $ 11.6 [6],[7]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon 13.33% [1]   12.92% [2] 13.33% [1] 13.33% [1] 13.33% [1] 13.33% [1] 12.92% [2] 12.92% [2] 12.92% [2] 12.92% [2]
Total first lien senior secured loans $ 9.7 [3],[4]   $ 9.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.7 [3],[4]   $ 9.5 [6],[7]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon 13.35% [1]   13.23% [2] 13.35% [1] 13.35% [1] 13.35% [1] 13.35% [1] 13.23% [2] 13.23% [2] 13.23% [2] 13.23% [2]
Total first lien senior secured loans $ 7.8 [3],[4]   $ 7.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.8 [3],[4]   $ 7.6 [6],[7]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon 13.33% [1]   12.92% [2] 13.33% [1] 13.33% [1] 13.33% [1] 13.33% [1] 12.92% [2] 12.92% [2] 12.92% [2] 12.92% [2]
Total first lien senior secured loans $ 5.7 [3],[4]   $ 5.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.7 [3],[4]   $ 5.2 [6],[7]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon 13.33% [1]   12.92% [2] 13.33% [1] 13.33% [1] 13.33% [1] 13.33% [1] 12.92% [2] 12.92% [2] 12.92% [2] 12.92% [2]
Total first lien senior secured loans $ 14.2 [3],[4],[13]   $ 13.7 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.2 [3],[4],[13]   $ 13.4 [6],[7],[14]                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon 13.33% [1]   12.92% [2] 13.33% [1] 13.33% [1] 13.33% [1] 13.33% [1] 12.92% [2] 12.92% [2] 12.92% [2] 12.92% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.0 [3],[4]   1.0 [6],[7],[14]                
Investment, Identifier [Axis]: Caerus Midco 3 S.à r.l.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.1   4.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.1   $ 4.1                
Investment, Identifier [Axis]: Caerus Midco 3 S.à r.l., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.65% [1]   9.83% [2] 10.65% [1] 10.65% [1] 10.65% [1] 10.65% [1] 9.83% [2] 9.83% [2] 9.83% [2] 9.83% [2]
Total first lien senior secured loans $ 5.4 [3],[4],[5]   $ 5.4 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.4 [3],[4],[5]   5.3 [6],[7],[8]                
Investment, Identifier [Axis]: CallMiner, Inc., Warrant to purchase up to 2,350,636 shares of Series 1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Calyx Energy III, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.92% [1]   12.37% [2] 12.92% [1] 12.92% [1] 12.92% [1] 12.92% [1] 12.37% [2] 12.37% [2] 12.37% [2] 12.37% [2]
Total first lien senior secured loans $ 53.4 [3],[4]   $ 57.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 53.4 [3],[4]   57.0 [6],[7]                
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.3   15.3                
Less: funded commitments (8.8)   (8.8)                
Total unfunded commitments 6.5   6.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.5   6.5                
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 19.6 [4]   $ 20.1 [7]                
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.66% [1]   9.13% [2] 9.66% [1] 9.66% [1] 9.66% [1] 9.66% [1] 9.13% [2] 9.13% [2] 9.13% [2] 9.13% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [16]   $ 0.0 [15]                
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.66% [1]   13.13% [2] 13.66% [1] 13.66% [1] 13.66% [1] 13.66% [1] 13.13% [2] 13.13% [2] 13.13% [2] 13.13% [2]
Total first lien senior secured loans $ 68.3 [3],[4]   $ 68.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 68.3 [3],[4]   68.3 [6],[7]                
Investment, Identifier [Axis]: Captive Resources Midco, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.2   1.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.2   1.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.2   $ 1.2                
Investment, Identifier [Axis]: Captive Resources Midco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.43% [1]   7.20% [2] 7.43% [1] 7.43% [1] 7.43% [1] 7.43% [1] 7.20% [2] 7.20% [2] 7.20% [2] 7.20% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0                
Less: funded commitments (5.0)   (3.4)                
Total unfunded commitments 0.0   1.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 1.6                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.50% [1]   11.00% [2] 11.50% [1] 11.50% [1] 11.50% [1] 11.50% [1] 11.00% [2] 11.00% [2] 11.00% [2] 11.00% [2]
Total first lien senior secured loans $ 5.0 [3],[4]   $ 3.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.7 [3],[4]   $ 3.0 [6],[7]                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.90% [1]   12.46% [2] 12.90% [1] 12.90% [1] 12.90% [1] 12.90% [1] 12.46% [2] 12.46% [2] 12.46% [2] 12.46% [2]
Total first lien senior secured loans $ 64.3 [3],[4]   $ 64.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 61.0 [3],[4]   57.8 [6],[7]                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 29.0 [4]   26.3 [7]                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc., Series A-2 preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.3 [4]   9.4 [7]                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc., Series A-3 preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 12.1 [4]   11.1 [7]                
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.5   20.4                
Less: funded commitments (9.2)   (9.0)                
Total unfunded commitments 1.3   11.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions (1.3)   (11.4)                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 12.2 [3],[4]   9.5 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 12.2 [3],[4]   4.0 [7],[10]                
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 9.9 [3],[4]   2.1 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.9 [3],[4]   0.9 [7],[10]                
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 6.8 [4],[9],[13]   6.8 [7],[10],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.5 [4],[9],[13]   2.9 [7],[10],[14]                
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.8 [4],[9],[13]   0.6 [7],[10],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [4],[9],[13]   0.2 [7],[10],[14]                
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.6   8.6                
Less: funded commitments (5.4)   (5.0)                
Total unfunded commitments 3.2   3.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.2   $ 3.6                
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 13.81% [1]   13.30% [2] 13.81% [1] 13.81% [1] 13.81% [1] 13.81% [1] 13.30% [2] 13.30% [2] 13.30% [2] 13.30% [2]
Total first lien senior secured loans $ 76.7 [3],[4]   $ 75.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 69.0 [3],[4]   $ 70.9 [6],[7]                
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.39% [1]   9.70% [2] 10.39% [1] 10.39% [1] 10.39% [1] 10.39% [1] 9.70% [2] 9.70% [2] 9.70% [2] 9.70% [2]
Total first lien senior secured loans $ 5.4 [3],[4]   $ 5.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.2 [3],[4]   4.7 [6],[7]                
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC, Membership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   2.9 [7]                
Investment, Identifier [Axis]: Chariot Buyer LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.3   12.3                
Less: funded commitments (3.2)   (3.5)                
Total unfunded commitments 9.1   8.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.1   $ 8.8                
Investment, Identifier [Axis]: Chariot Buyer LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.84% [1]   7.38% [2] 7.84% [1] 7.84% [1] 7.84% [1] 7.84% [1] 7.38% [2] 7.38% [2] 7.38% [2] 7.38% [2]
Total first lien senior secured loans $ 3.2 [4]   $ 3.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.0 [4]   $ 3.2 [7]                
Investment, Identifier [Axis]: Chariot Buyer LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.13% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 134.4 [3],[4]   $ 134.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 127.7 [3],[4]   126.3 [6],[7]                
Investment, Identifier [Axis]: Cheyenne Petroleum Company Limited Partnership, CPC 2001 LLC and Mill Shoals LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.5   9.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 9.5   9.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.5   $ 9.5                
Investment, Identifier [Axis]: Cheyenne Petroleum Company Limited Partnership, CPC 2001 LLC and Mill Shoals LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.00% [1]   13.69% [2] 14.00% [1] 14.00% [1] 14.00% [1] 14.00% [1] 13.69% [2] 13.69% [2] 13.69% [2] 13.69% [2]
Total first lien senior secured loans $ 49.3 [3],[4]   $ 49.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 49.3 [3],[4]   $ 47.8 [6],[7]                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 68.2                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 66.9                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 30.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 29.4                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 20.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 19.6                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 15.5                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 15.2                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.23%         15.23% 15.23% 15.23% 15.23%
Total first lien senior secured loans [6],[7]     $ 12.2                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 11.9                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 6                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 4.9                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 4.8                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 7                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 3.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 3.0                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., First lien senior secured loan 8                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     15.48%         15.48% 15.48% 15.48% 15.48%
Total first lien senior secured loans [6],[7]     $ 3.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     3.0                
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., Warrants to purchase units of shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7],[8]     8.8                
Investment, Identifier [Axis]: CoLTs 2005-1 Ltd.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   0.0                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: CoLTs 2005-1 Ltd., Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [5]   0.0 [8]                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.8   7.8                
Less: funded commitments (2.5)   (2.5)                
Total unfunded commitments 5.3   5.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 5.3   5.3                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4]   $ 0.0 [7]                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.17% [1]   9.63% [2] 10.17% [1] 10.17% [1] 10.17% [1] 10.17% [1] 9.63% [2] 9.63% [2] 9.63% [2] 9.63% [2]
Total first lien senior secured loans $ 30.1 [3]   $ 30.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 28.6 [3]   $ 29.0 [6],[7]                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.17% [1]   9.63% [2] 10.17% [1] 10.17% [1] 10.17% [1] 10.17% [1] 9.63% [2] 9.63% [2] 9.63% [2] 9.63% [2]
Total first lien senior secured loans $ 2.5 [3],[4]   $ 2.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [3],[4]   2.4 [6],[7]                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.2 [4]   4.0 [7]                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 72.3 [4]   $ 69.7 [7]                
Investment, Identifier [Axis]: Color Intermediate, LLC First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   10.08% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 10.08% [2] 10.08% [2] 10.08% [2] 10.08% [2]
Total first lien senior secured loans $ 20.3 [3],[4]   $ 20.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.9 [3],[4]   19.5 [6],[7]                
Investment, Identifier [Axis]: Commercial Trailer Leasing, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   0.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.6   0.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.6   $ 0.6                
Investment, Identifier [Axis]: Commercial Trailer Leasing, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.04% [1]   10.33% [2] 11.04% [1] 11.04% [1] 11.04% [1] 11.04% [1] 10.33% [2] 10.33% [2] 10.33% [2] 10.33% [2]
Total first lien senior secured loans $ 24.9 [3],[4]   $ 33.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 24.9 [3],[4]   $ 33.3 [6],[7]                
Investment, Identifier [Axis]: Commercial Trailer Leasing, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.00% [1]   13.00% [2] 13.00% [1] 13.00% [1] 13.00% [1] 13.00% [1] 13.00% [2] 13.00% [2] 13.00% [2] 13.00% [2]
Total first lien senior secured loans $ 19.9 [4]   $ 19.9 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.5 [4]   19.5 [7]                
Investment, Identifier [Axis]: Community Brands ParentCo, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.2   7.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 7.2   7.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.2   7.2                
Investment, Identifier [Axis]: Community Brands ParentCo, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.0 [4]   $ 6.4 [7]                
Investment, Identifier [Axis]: Community Brands ParentCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.17% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.17% [2] 10.17% [2] 10.17% [2] 10.17% [2]
Total first lien senior secured loans $ 10.6 [3],[4]   $ 10.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.4 [3],[4]   10.4 [6],[7]                
Investment, Identifier [Axis]: Compex Legal Services, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.6   3.6                
Less: funded commitments (2.2)   (1.8)                
Total unfunded commitments 1.4   1.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.4   $ 1.8                
Investment, Identifier [Axis]: Compex Legal Services, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.45% [1]   9.51% [2] 10.45% [1] 10.45% [1] 10.45% [1] 10.45% [1] 9.51% [2] 9.51% [2] 9.51% [2] 9.51% [2]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 1.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.0 [3],[4]   1.8 [6],[7]                
Investment, Identifier [Axis]: Compex Legal Services, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.20%     10.20% 10.20% 10.20% 10.20%        
Total first lien senior secured loans [3],[4] $ 0.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.2                    
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9   1.9                
Less: funded commitments (1.9)   (0.8)                
Total unfunded commitments 0.0   1.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 1.1                
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   10.59% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 10.59% [2] 10.59% [2] 10.59% [2] 10.59% [2]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 0.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4]   $ 0.3 [6],[7]                
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.44% [1]   10.58% [2] 11.44% [1] 11.44% [1] 11.44% [1] 11.44% [1] 10.58% [2] 10.58% [2] 10.58% [2] 10.58% [2]
Total first lien senior secured loans $ 1.9 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.8 [3],[4]   $ 0.7 [6],[7]                
Investment, Identifier [Axis]: Computer Services, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.15% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.15% [2] 11.15% [2] 11.15% [2] 11.15% [2]
Total first lien senior secured loans $ 34.1 [3],[4]   $ 34.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 33.0 [3],[4]   33.0 [6],[7]                
Investment, Identifier [Axis]: Concert Golf Partners Holdco LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.1   3.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.1   3.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.1   3.1                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.5   14.2                
Less: funded commitments (0.9)   (0.8)                
Total unfunded commitments 12.6   13.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 12.6   13.4                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.2 [4],[5]   $ 6.5 [7],[8]                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   10.48% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 11.7 [3],[4],[5]   $ 11.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.3 [3],[4],[5]   $ 11.4 [6],[7],[8]                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.79% [1]   10.48% [2] 10.79% [1] 10.79% [1] 10.79% [1] 10.79% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 74.6 [4],[5]   $ 74.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 72.4 [4],[5]   $ 72.6 [6],[7],[8]                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.24% [1]   8.39% [2] 9.24% [1] 9.24% [1] 9.24% [1] 9.24% [1] 8.39% [2] 8.39% [2] 8.39% [2] 8.39% [2]
Total first lien senior secured loans $ 28.0 [3],[4],[5]   $ 26.9 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 27.1 [3],[4],[5]   $ 26.1 [7],[8]                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.72% [1]   8.32% [2] 10.72% [1] 10.72% [1] 10.72% [1] 10.72% [1] 8.32% [2] 8.32% [2] 8.32% [2] 8.32% [2]
Total first lien senior secured loans $ 0.7 [3],[4],[5]   $ 0.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.7 [3],[4],[5]   0.8 [6],[7],[8]                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 9.07%     9.07% 9.07% 9.07% 9.07%        
Total first lien senior secured loans [3],[4],[5] $ 0.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[5] 0.2                    
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., Series A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4],[5]   $ 0.0 [7],[8]                
Investment, Identifier [Axis]: Continental Acquisition Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.51% [1]   11.48% [2] 11.51% [1] 11.51% [1] 11.51% [1] 11.51% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 36.1 [3],[4]   $ 36.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.2 [3],[4]   $ 33.3 [6],[7]                
Investment, Identifier [Axis]: Continental Acquisition Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.55% [1]   11.48% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 5.4 [3],[4]   $ 5.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.9 [3],[4]   4.9 [6],[7]                
Investment, Identifier [Axis]: Continental Café, LLC and Infinity Ovation Yacht Charters, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.0   8.0                
Less: funded commitments (0.9)   (0.7)                
Total unfunded commitments 7.1   7.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 7.1   $ 7.3                
Investment, Identifier [Axis]: Continental Café, LLC and Infinity Ovation Yacht Charters, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.90% [1]   11.38% [2] 11.90% [1] 11.90% [1] 11.90% [1] 11.90% [1] 11.38% [2] 11.38% [2] 11.38% [2] 11.38% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Continental Café, LLC and Infinity Ovation Yacht Charters, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.00% [1]   13.50% [2] 14.00% [1] 14.00% [1] 14.00% [1] 14.00% [1] 13.50% [2] 13.50% [2] 13.50% [2] 13.50% [2]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.9 [3],[4]   0.7 [6],[7]                
Investment, Identifier [Axis]: Convera International Holdings Limited and Convera International Financial S.A R.L.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.3   2.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.3   $ 2.3                
Investment, Identifier [Axis]: Convera International Holdings Limited and Convera International Financial S.A R.L., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.65% [1]   10.33% [2] 10.65% [1] 10.65% [1] 10.65% [1] 10.65% [1] 10.33% [2] 10.33% [2] 10.33% [2] 10.33% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 62.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 62.8 [6],[7],[8]                
Investment, Identifier [Axis]: Convey Health Solutions, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.25% [1]   9.48% [2] 10.25% [1] 10.25% [1] 10.25% [1] 10.25% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 2.7 [3],[4],[5]   $ 2.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.6 [3],[4],[5]   $ 2.6 [6],[7],[8]                
Investment, Identifier [Axis]: Convey Health Solutions, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.25% [1]   9.83% [2] 10.25% [1] 10.25% [1] 10.25% [1] 10.25% [1] 9.83% [2] 9.83% [2] 9.83% [2] 9.83% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investment, Identifier [Axis]: Convey Health Solutions, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.25% [1]   9.93% [2] 10.25% [1] 10.25% [1] 10.25% [1] 10.25% [1] 9.93% [2] 9.93% [2] 9.93% [2] 9.93% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4],[5]   0.1 [6],[7],[8]                
Investment, Identifier [Axis]: CoreLogic, Inc. and T-VIII Celestial Co-Invest LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 38.9   38.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 38.9   38.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 38.9   38.9                
Investment, Identifier [Axis]: CoreLogic, Inc. and T-VIII Celestial Co-Invest LP, Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 48.8 [4]   $ 48.8 [7]                
Investment, Identifier [Axis]: CoreLogic, Inc. and T-VIII Celestial Co-Invest LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.38% [1]   10.94% [2] 11.38% [1] 11.38% [1] 11.38% [1] 11.38% [1] 10.94% [2] 10.94% [2] 10.94% [2] 10.94% [2]
Total first lien senior secured loans $ 155.7 [3],[4]   $ 155.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 132.3 [3],[4]   129.2 [6],[7]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., Common equity                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4],[5]   $ 0.0 [7],[8]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.09% [1]   10.31% [2] 10.09% [1] 10.09% [1] 10.09% [1] 10.09% [1] 10.31% [2] 10.31% [2] 10.31% [2] 10.31% [2]
Total first lien senior secured loans $ 4.4 [3],[4],[5]   $ 6.2 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.3 [3],[4],[5]   $ 6.2 [6],[7],[8]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   9.06% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 9.06% [2] 9.06% [2] 9.06% [2] 9.06% [2]
Total first lien senior secured loans $ 0.2 [3],[4],[5]   $ 4.4 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4],[5]   $ 4.3 [6],[7],[8]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.09% [1]   11.06% [2] 12.09% [1] 12.09% [1] 12.09% [1] 12.09% [1] 11.06% [2] 11.06% [2] 11.06% [2] 11.06% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.09% [1]   9.06% [2] 10.09% [1] 10.09% [1] 10.09% [1] 10.09% [1] 9.06% [2] 9.06% [2] 9.06% [2] 9.06% [2]
Total first lien senior secured loans $ 6.3 [3],[4],[5]   $ 6.3 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.2 [3],[4],[5]   6.2 [6],[7],[8]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., Preferred equity                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [4],[5]   0.7 [7],[8]                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc., and Cority Parent, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.1   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.1   0.1                
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 38.7   38.7                
Less: funded commitments (24.5)   (22.7)                
Total unfunded commitments 14.2   16.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 14.2   16.0                
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., Class A-1 common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 17.4 [4]   $ 15.2 [7]                
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.96% [1]   7.51% [2] 7.96% [1] 7.96% [1] 7.96% [1] 7.96% [1] 7.51% [2] 7.51% [2] 7.51% [2] 7.51% [2]
Total first lien senior secured loans $ 23.8 [4],[13]   $ 21.9 [7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 21.7 [4],[13]   $ 19.7 [7],[14]                
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.34% [1]   10.88% [2] 11.34% [1] 11.34% [1] 11.34% [1] 11.34% [1] 10.88% [2] 10.88% [2] 10.88% [2] 10.88% [2]
Total first lien senior secured loans $ 137.5 [3],[4]   $ 137.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 127.9 [3],[4]   123.7 [6],[7]                
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 112.0 [4]   109.4 [7]                
Investment, Identifier [Axis]: Coupa Holdings, LLC and Coupa Software Incorporated                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9                    
Less: funded commitments 0.0                    
Total unfunded commitments 0.9                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.9                    
Investment, Identifier [Axis]: Coupa Holdings, LLC and Coupa Software Incorporated, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.29%     12.29% 12.29% 12.29% 12.29%        
Total first lien senior secured loans [3],[4] $ 9.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 8.8                    
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.2   22.2                
Less: funded commitments (1.5)   (1.5)                
Total unfunded commitments 20.7   20.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 20.7   20.7                
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC, Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.1   $ 5.5                
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.91% [1]   9.16% [2] 9.91% [1] 9.91% [1] 9.91% [1] 9.91% [1] 9.16% [2] 9.16% [2] 9.16% [2] 9.16% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.91% [1]   9.66% [2] 9.91% [1] 9.91% [1] 9.91% [1] 9.91% [1] 9.66% [2] 9.66% [2] 9.66% [2] 9.66% [2]
Total first lien senior secured loans $ 1.5 [3],[4]   $ 1.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.5 [3],[4]   1.5 [6],[7]                
Investment, Identifier [Axis]: Coyote Buyer, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.8   5.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.8   5.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 5.8   5.8                
Investment, Identifier [Axis]: CrossCountry Mortgage, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     56.3                
Less: funded commitments     0.0                
Total unfunded commitments     56.3                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 56.3                
Investment, Identifier [Axis]: CrossCountry Mortgage, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.95% [1]   11.73% [2] 11.95% [1] 11.95% [1] 11.95% [1] 11.95% [1] 11.73% [2] 11.73% [2] 11.73% [2] 11.73% [2]
Total first lien senior secured loans $ 93.8 [3],[4]   $ 93.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 92.8 [3],[4]   92.8 [6],[7]                
Investment, Identifier [Axis]: Crown CT Parent Inc., Crown CT HoldCo Inc. and Crown CT Management LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.2   3.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.2   3.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.2   3.2                
Investment, Identifier [Axis]: Crown CT Parent Inc., Crown CT HoldCo Inc. and Crown CT Management LLC, Class A shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [4]   1.9 [7]                
Investment, Identifier [Axis]: Crown CT Parent Inc., Crown CT HoldCo Inc. and Crown CT Management LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [4]   $ 0.3 [7]                
Investment, Identifier [Axis]: Crown CT Parent Inc., Crown CT HoldCo Inc. and Crown CT Management LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.11% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.11% [2] 10.11% [2] 10.11% [2] 10.11% [2]
Total first lien senior secured loans $ 24.5 [3],[4]   $ 24.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.2 [3],[4]   24.5 [6],[7]                
Investment, Identifier [Axis]: DFC Global Facility Borrower III LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 96.7   96.7                
Less: funded commitments (81.0)   (79.3)                
Total unfunded commitments 15.7   17.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 15.7   $ 17.4                
Investment, Identifier [Axis]: DFC Global Facility Borrower III LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.16% [1]   11.62% [2] 12.16% [1] 12.16% [1] 12.16% [1] 12.16% [1] 11.62% [2] 11.62% [2] 11.62% [2] 11.62% [2]
Total first lien senior secured loans $ 162.0 [3],[4],[5],[17]   $ 158.6 [6],[7],[8],[18]                
Participating interest sold 80.4   79.0                
Secured borrowings 80.4   79.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 162.0 [3],[4],[5],[17]   $ 158.6 [6],[7],[8],[18]                
Investment, Identifier [Axis]: DFC Global Facility Borrower III LLC, First lien senior secured revolving loan, Secured borrowing                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.16%   11.62% 12.16% 12.16% 12.16% 12.16% 11.62% 11.62% 11.62% 11.62%
Investment, Identifier [Axis]: DFS Holding Company, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments $ 0.4                    
Less: funded commitments 0.0                    
Total unfunded commitments 0.4                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.4                    
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 11.78% [1]   9.44% [2] 11.78% [1] 11.78% [1] 11.78% [1] 11.78% [1] 9.44% [2] 9.44% [2] 9.44% [2] 9.44% [2]
Total first lien senior secured loans $ 2.0 [3]   $ 164.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.9 [3]   $ 164.9 [6],[7]                
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.38%         10.38% 10.38% 10.38% 10.38%
Total first lien senior secured loans [6],[7]     $ 6.5                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 6.5                
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.38%         10.38% 10.38% 10.38% 10.38%
Total first lien senior secured loans [6],[7]     $ 4.3                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     4.3                
Investment, Identifier [Axis]: DRS Holdings III, Inc. and DRS Holdings I, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.8   10.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 10.8   10.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 10.8   10.8                
Investment, Identifier [Axis]: DRS Holdings III, Inc. and DRS Holdings I, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.2 [4]   $ 7.2 [7]                
Investment, Identifier [Axis]: DRS Holdings III, Inc. and DRS Holdings I, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.90% [1]   10.47% [2] 10.90% [1] 10.90% [1] 10.90% [1] 10.90% [1] 10.47% [2] 10.47% [2] 10.47% [2] 10.47% [2]
Total first lien senior secured loans $ 27.9 [3],[4]   $ 28.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 26.2 [3],[4]   $ 26.8 [6],[7]                
Investment, Identifier [Axis]: DRS Holdings III, Inc. and DRS Holdings I, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.90% [1]   10.47% [2] 10.90% [1] 10.90% [1] 10.90% [1] 10.90% [1] 10.47% [2] 10.47% [2] 10.47% [2] 10.47% [2]
Total first lien senior secured loans $ 25.7 [3],[4]   $ 25.8 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.2 [3],[4]   24.8 [6]                
Investment, Identifier [Axis]: DS Admiral Bidco, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.1   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.1   $ 0.1                
Investment, Identifier [Axis]: DS Admiral Bidco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.40% [1]   10.16% [2] 11.40% [1] 11.40% [1] 11.40% [1] 11.40% [1] 10.16% [2] 10.16% [2] 10.16% [2] 10.16% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.3 [4]   6.3 [7]                
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc., Class B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4]   $ 0.0 [7]                
Investment, Identifier [Axis]: Datix Bidco Limited, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.00% [1]   8.95% [2] 9.00% [1] 9.00% [1] 9.00% [1] 9.00% [1] 8.95% [2] 8.95% [2] 8.95% [2] 8.95% [2]
Total first lien senior secured loans $ 4.3 [4],[5]   $ 4.3 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.2 [4],[5]   $ 4.2 [7],[8]                
Investment, Identifier [Axis]: Datix Bidco Limited, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.68% [1]   12.20% [2] 12.68% [1] 12.68% [1] 12.68% [1] 12.68% [1] 12.20% [2] 12.20% [2] 12.20% [2] 12.20% [2]
Total first lien senior secured loans $ 0.7 [4],[5]   $ 0.7 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.7 [4],[5]   $ 0.7 [7],[8]                
Investment, Identifier [Axis]: Dcert Buyer, Inc., DCert Preferred Holdings, Inc. and Destiny Digital Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.70%         8.70% 8.70% 8.70% 8.70%
Total first lien senior secured loans [7]     $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     $ 0.9                
Investment, Identifier [Axis]: Dcert Buyer, Inc., DCert Preferred Holdings, Inc. and Destiny Digital Holdings, L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.70% [1]   11.70% [2] 11.70% [1] 11.70% [1] 11.70% [1] 11.70% [1] 11.70% [2] 11.70% [2] 11.70% [2] 11.70% [2]
Total first lien senior secured loans $ 11.0 [4]   $ 11.0 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.8 [4]   10.7 [7]                
Investment, Identifier [Axis]: Dcert Buyer, Inc., DCert Preferred Holdings, Inc. and Destiny Digital Holdings, L.P., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 137.7 [4]   134.6 [7]                
Investment, Identifier [Axis]: Dcert Buyer, Inc., DCert Preferred Holdings, Inc. and Destiny Digital Holdings, L.P., Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 12.2 [4]   12.5 [7]                
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 16.5   16.5                
Less: funded commitments (4.7)   (6.6)                
Total unfunded commitments 11.8   9.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 11.8   9.9                
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.3 [4]   $ 9.4 [7]                
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.05% [1]   10.73% [2] 11.05% [1] 11.05% [1] 11.05% [1] 11.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 148.2 [3],[4]   $ 148.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 145.3 [3],[4]   $ 145.6 [6],[7]                
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.79% [1]   10.73% [2] 10.79% [1] 10.79% [1] 10.79% [1] 10.79% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 4.7 [3],[4]   $ 6.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.6 [3],[4]   6.5 [6],[7]                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.4   11.4                
Less: funded commitments (3.9)   0.0                
Total unfunded commitments 7.5   11.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.5   11.4                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.7 [4]   $ 2.4 [7]                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.62% [1]   10.52% [2] 10.62% [1] 10.62% [1] 10.62% [1] 10.62% [1] 10.52% [2] 10.52% [2] 10.52% [2] 10.52% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.62% [1]   10.52% [2] 10.62% [1] 10.62% [1] 10.62% [1] 10.62% [1] 10.52% [2] 10.52% [2] 10.52% [2] 10.52% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.50%     12.50% 12.50% 12.50% 12.50%        
Total first lien senior secured loans [3],[4] $ 2.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 2.1                    
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.53%     10.53% 10.53% 10.53% 10.53%        
Total first lien senior secured loans [3],[4] $ 1.8                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 1.8                    
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.2   2.2                
Less: funded commitments (0.7)   (0.7)                
Total unfunded commitments 1.5   1.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.5   $ 1.5                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.06% [1]   10.63% [2] 11.06% [1] 11.06% [1] 11.06% [1] 11.06% [1] 10.63% [2] 10.63% [2] 10.63% [2] 10.63% [2]
Total first lien senior secured loans $ 14.9 [3],[4]   $ 35.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.6 [3],[4]   $ 35.2 [6],[7]                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.09% [1]   10.63% [2] 11.09% [1] 11.09% [1] 11.09% [1] 11.09% [1] 10.63% [2] 10.63% [2] 10.63% [2] 10.63% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 2.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 2.0 [6],[7]                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.09% [1]   10.63% [2] 11.09% [1] 11.09% [1] 11.09% [1] 11.09% [1] 10.63% [2] 10.63% [2] 10.63% [2] 10.63% [2]
Total first lien senior secured loans $ 0.7 [3],[4],[13]   $ 0.7 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [3],[4],[13]   0.7 [6],[7],[14]                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 14.5 [4]   13.8 [7]                
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.3   2.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 2.3   2.3                
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc., Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.3 [4]   $ 1.2 [7]                
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.56% [1]   10.03% [2] 10.56% [1] 10.56% [1] 10.56% [1] 10.56% [1] 10.03% [2] 10.03% [2] 10.03% [2] 10.03% [2]
Total first lien senior secured loans $ 15.8 [3],[4]   $ 15.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.8 [3],[4]   $ 15.8 [6],[7]                
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.56% [1]   10.03% [2] 10.56% [1] 10.56% [1] 10.56% [1] 10.56% [1] 10.03% [2] 10.03% [2] 10.03% [2] 10.03% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.56% [1]   10.03% [2] 10.56% [1] 10.56% [1] 10.56% [1] 10.56% [1] 10.03% [2] 10.03% [2] 10.03% [2] 10.03% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Drilling Info Holdings, Inc. and Titan DI Preferred Holdings, Inc., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 42.5 [4]   $ 41.6 [7]                
Investment, Identifier [Axis]: Drilling Info Holdings, Inc. and Titan DI Preferred Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.09% [1]   12.63% [2] 13.09% [1] 13.09% [1] 13.09% [1] 13.09% [1] 12.63% [2] 12.63% [2] 12.63% [2] 12.63% [2]
Total first lien senior secured loans $ 25.0 [4]   $ 25.0 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.8 [4]   24.8 [7]                
Investment, Identifier [Axis]: Dye & Durham Corporation                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.1   18.2                
Less: funded commitments (5.0)   (5.0)                
Total unfunded commitments 10.1   13.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 10.1   $ 13.2                
Investment, Identifier [Axis]: Dye & Durham Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.78% [1]   10.69% [2] 10.78% [1] 10.78% [1] 10.78% [1] 10.78% [1] 10.69% [2] 10.69% [2] 10.69% [2] 10.69% [2]
Total first lien senior secured loans $ 3.2 [3],[4],[5]   $ 40.0 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.2 [3],[4],[5]   $ 40.0 [6],[7],[8]                
Investment, Identifier [Axis]: Dye & Durham Corporation, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.78% [1]   11.20% [2] 10.78% [1] 10.78% [1] 10.78% [1] 10.78% [1] 11.20% [2] 11.20% [2] 11.20% [2] 11.20% [2]
Total first lien senior secured loans $ 5.0 [3],[4],[5]   $ 5.0 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.0 [3],[4],[5]   5.0 [6],[7],[8]                
Investment, Identifier [Axis]: Dynamic NC Aerospace Holdings, LLC and Dynamic NC Investment Holdings, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.1   7.1                
Less: funded commitments (0.9)   0.0                
Total unfunded commitments 6.2   7.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.2   7.1                
Investment, Identifier [Axis]: Dynamic NC Aerospace Holdings, LLC and Dynamic NC Investment Holdings, LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.1   $ 9.0                
Investment, Identifier [Axis]: Dynamic NC Aerospace Holdings, LLC and Dynamic NC Investment Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.65% [1]   11.65% [2] 11.65% [1] 11.65% [1] 11.65% [1] 11.65% [1] 11.65% [2] 11.65% [2] 11.65% [2] 11.65% [2]
Total first lien senior secured loans $ 23.2 [3],[4]   $ 23.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 23.2 [3],[4]   23.2 [6],[7]                
Investment, Identifier [Axis]: Dynamic NC Aerospace Holdings, LLC and Dynamic NC Investment Holdings, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.05%     12.05% 12.05% 12.05% 12.05%        
Total first lien senior secured loans [3],[4] $ 0.9                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.9                    
Investment, Identifier [Axis]: EP Purchaser, LLC and TPG VIII EP Co-Invest II, L.P., Partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.7 [4],[5]   $ 11.7 [7],[8]                
Investment, Identifier [Axis]: EP Purchaser, LLC and TPG VIII EP Co-Invest II, L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.23% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 177.9 [3],[4]   $ 177.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 177.9 [3],[4]   176.1 [6],[7]                
Investment, Identifier [Axis]: EP Wealth Advisors, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.0   14.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 10.0   14.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 10.0   $ 14.1                
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.73% [1]   10.01% [2] 10.73% [1] 10.73% [1] 10.73% [1] 10.73% [1] 10.01% [2] 10.01% [2] 10.01% [2] 10.01% [2]
Total first lien senior secured loans $ 4.2 [3],[4]   $ 5.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.2 [3],[4]   $ 5.6 [6],[7]                
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.55% [1]   10.23% [2] 10.55% [1] 10.55% [1] 10.55% [1] 10.55% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.4 [3],[4]   $ 0.4 [6],[7]                
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.55% [1]   10.23% [2] 10.55% [1] 10.55% [1] 10.55% [1] 10.55% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [1]   10.11% [2] 10.42% [1] 10.42% [1] 10.42% [1] 10.42% [1] 10.11% [2] 10.11% [2] 10.11% [2] 10.11% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: EPS NASS Parent, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.5                
Less: funded commitments (1.0)   (0.8)                
Total unfunded commitments 0.5   0.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.5   $ 0.7                
Investment, Identifier [Axis]: EPS NASS Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.48% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: EPS NASS Parent, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.48% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 0.8 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.9 [3],[4]   0.8 [6],[7],[14]                
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   2.3                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 1.3   (1.9)                
Fair Value 4.4   3.1                
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC, Class A-1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.3 [4]   3.0 [7]                
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC, Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2   0.1 [7]                
Investment, Identifier [Axis]: ESHA Research, LLC and RMCF VI CIV XLVIII, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.1   1.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.1   1.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.1   $ 1.1                
Investment, Identifier [Axis]: ESHA Research, LLC and RMCF VI CIV XLVIII, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.99% [1]   10.07% [2] 10.99% [1] 10.99% [1] 10.99% [1] 10.99% [1] 10.07% [2] 10.07% [2] 10.07% [2] 10.07% [2]
Total first lien senior secured loans $ 6.8 [3],[4]   $ 6.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.7 [3],[4]   6.7 [6],[7]                
Investment, Identifier [Axis]: ESHA Research, LLC and RMCF VI CIV XLVIII, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.5   6.0                
Investment, Identifier [Axis]: Eagle Football Holdings BidCo Limited, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.83%     12.83% 12.83% 12.83% 12.83%        
Total first lien senior secured loans $ 43.1 [4],[5]   25.5 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 39.6 [4],[5]   $ 23.9 [7],[8]                
Investment, Identifier [Axis]: Eagle Football Holdings BidCo Limited, Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     12.30%         12.30% 12.30% 12.30% 12.30%
Total first lien senior secured loans 21.8 [4],[5]   $ 41.7 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 21.2 [4],[5]   40.5 [7],[8]                
Investment, Identifier [Axis]: Eagle Football Holdings BidCo Limited, Senior subordinated loan 3                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [4],[5] 4.5                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4],[5] 4.3                    
Investment, Identifier [Axis]: Eagle Football Holdings BidCo Limited, Warrant to purchase shares of ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4],[5] 3.4                    
Investment, Identifier [Axis]: Eagle Football Holdings BidCo Limited, Warrant to purchase shares of ordinary shares 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4],[5] 0.6                    
Investment, Identifier [Axis]: Eagle Football Holdings BidCo Limited, Warrant to purchase shares of ordinary shares 3                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4],[5] 0.0                    
Investment, Identifier [Axis]: Eckler Industries, Inc. and Eckler Purchaser LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   8.8                
Redemptions (cost) 0.0   57.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   (57.0)                
Net unrealized gains (losses): 0.0   25.1                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Eckler Purchaser LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc, Preferred equity                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.3 [4]   5.3 [7]                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1                
Less: funded commitments (3.4)   (4.1)                
Total unfunded commitments 0.7   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.7   $ 0.0                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.00% [1]   10.74% [2] 11.00% [1] 11.00% [1] 11.00% [1] 11.00% [1] 10.74% [2] 10.74% [2] 10.74% [2] 10.74% [2]
Total first lien senior secured loans $ 49.9 [3]   $ 50.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 48.9 [3]   $ 48.5 [6],[7]                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.18% [1]   10.68% [2] 11.18% [1] 11.18% [1] 11.18% [1] 11.18% [1] 10.68% [2] 10.68% [2] 10.68% [2] 10.68% [2]
Total first lien senior secured loans $ 11.3 [3],[4]   $ 11.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.1 [3],[4]   $ 11.0 [6],[7]                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.18% [1]   10.68% [2] 11.18% [1] 11.18% [1] 11.18% [1] 11.18% [1] 10.68% [2] 10.68% [2] 10.68% [2] 10.68% [2]
Total first lien senior secured loans $ 5.7 [3],[4]   $ 5.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.6 [3],[4]   $ 5.6 [6],[7]                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.86% [1]   10.51% [2] 10.86% [1] 10.86% [1] 10.86% [1] 10.86% [1] 10.51% [2] 10.51% [2] 10.51% [2] 10.51% [2]
Total first lien senior secured loans $ 3.4 [3],[4]   $ 4.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.3 [3],[4]   4.0 [6],[7]                
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 17.1   17.1                
Less: funded commitments (1.5)   (1.5)                
Total unfunded commitments 15.6   15.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 15.6   $ 15.6                
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.38% [1]   10.86% [2] 11.38% [1] 11.38% [1] 11.38% [1] 11.38% [1] 10.86% [2] 10.86% [2] 10.86% [2] 10.86% [2]
Total first lien senior secured loans $ 9.1 [3],[4]   $ 10.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.7 [3],[4]   $ 10.0 [6],[7]                
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.39% [1]   9.47% [2] 11.39% [1] 11.39% [1] 11.39% [1] 11.39% [1] 9.47% [2] 9.47% [2] 9.47% [2] 9.47% [2]
Total first lien senior secured loans $ 10.2 [3],[4]   $ 9.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.7 [3],[4]   $ 9.0 [6],[7]                
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.40% [1]   10.36% [2] 11.40% [1] 11.40% [1] 11.40% [1] 11.40% [1] 10.36% [2] 10.36% [2] 10.36% [2] 10.36% [2]
Total first lien senior secured loans $ 1.4 [3],[4],[13]   $ 1.4 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.3 [3],[4],[13]   1.4 [6],[7],[14]                
Investment, Identifier [Axis]: Emergency Communications Network, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.9   6.8                
Less: funded commitments (6.9)   (6.8)                
Total unfunded commitments 0.0   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Emergency Communications Network, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 12.43% [1]   11.84% [2] 12.43% [1] 12.43% [1] 12.43% [1] 12.43% [1] 11.84% [2] 11.84% [2] 11.84% [2] 11.84% [2]
Total first lien senior secured loans $ 49.1 [3],[4]   $ 48.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 44.2 [3],[4]   $ 43.6 [6],[7]                
Investment, Identifier [Axis]: Emergency Communications Network, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon 12.66% [1]   12.15% [2] 12.66% [1] 12.66% [1] 12.66% [1] 12.66% [1] 12.15% [2] 12.15% [2] 12.15% [2] 12.15% [2]
Total first lien senior secured loans $ 6.9 [3],[4]   $ 6.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.2 [3],[4]   $ 6.1 [6],[7]                
Investment, Identifier [Axis]: Ensemble RCM, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.78% [1]   9.19% [2] 9.78% [1] 9.78% [1] 9.78% [1] 9.78% [1] 9.19% [2] 9.19% [2] 9.19% [2] 9.19% [2]
Total first lien senior secured loans $ 2.5 [3]   $ 2.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.5 [3]   2.5 [6],[7]                
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.5   14.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 14.5   14.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 14.5   $ 14.5                
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.99% [1]   6.69% [2] 8.99% [1] 8.99% [1] 8.99% [1] 8.99% [1] 6.69% [2] 6.69% [2] 6.69% [2] 6.69% [2]
Total first lien senior secured loans $ 5.7 [4]   $ 5.6 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.5 [4]   $ 5.5 [7],[8]                
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   9.98% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7],[8]                
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   9.98% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7],[8]                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.0   28.0                
Less: funded commitments (11.6)   (6.2)                
Total unfunded commitments 16.4   21.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 16.4   21.8                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 43.7 [4]   $ 42.0 [7]                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   9.49% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 9.49% [2] 9.49% [2] 9.49% [2] 9.49% [2]
Total first lien senior secured loans $ 77.9 [3],[4]   $ 78.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 76.4 [3],[4]   $ 76.5 [6],[7]                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   9.49% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 9.49% [2] 9.49% [2] 9.49% [2] 9.49% [2]
Total first lien senior secured loans $ 48.1 [3],[4]   $ 48.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 47.1 [3],[4]   $ 47.2 [6],[7]                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   9.71% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 9.71% [2] 9.71% [2] 9.71% [2] 9.71% [2]
Total first lien senior secured loans $ 25.1 [3],[4]   $ 19.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 24.7 [3],[4]   $ 19.2 [6],[7]                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     14.94%         14.94% 14.94% 14.94% 14.94%
Total first lien senior secured loans [6],[7]     $ 5.6                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     5.5                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.59%     10.59% 10.59% 10.59% 10.59%        
Total first lien senior secured loans $ 2.8 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.7 [16]   0.0 [15]                
Investment, Identifier [Axis]: European Capital UK SME Debt LP                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.8                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.4   2.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.6   0.4                
Fair Value 27.1   26.5                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 55.6   54.3                
Less: funded commitments (50.3)   (49.1)                
Total unfunded commitments 5.3   5.2                
Less: commitments substantially at discretion of the Company (5.3)   (5.2)                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: European Capital UK SME Debt LP, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 27.1 [5]   26.5 [8]                
Investment, Identifier [Axis]: Everspin Technologies, Inc., Warrant to purchase up to 18,461 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Evolent Health LLC and Evolent Health, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.79%     10.79% 10.79% 10.79% 10.79%        
Total first lien senior secured loans [3],[4],[5] $ 34.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[5] $ 33.0                    
Investment, Identifier [Axis]: Evolent Health LLC and Evolent Health, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.04%     11.04% 11.04% 11.04% 11.04%        
Total first lien senior secured loans [3],[4],[5] $ 7.8                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[5] $ 7.6                    
Investment, Identifier [Axis]: Evolent Health LLC and Evolent Health, Inc., Series A preferred shares                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.06%     11.06% 11.06% 11.06% 11.06%        
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[5] $ 4.3                    
Investment, Identifier [Axis]: Evolent Health LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.23%         10.23% 10.23% 10.23% 10.23%
Total first lien senior secured loans [6],[7],[8]     $ 7.8                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7],[8]     $ 7.7                
Investment, Identifier [Axis]: Excelligence Holdings Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.09% [1]   10.73% [2] 11.09% [1] 11.09% [1] 11.09% [1] 11.09% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 9.2 [3],[4]   $ 9.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.2 [3],[4]   9.2 [6],[7]                
Investment, Identifier [Axis]: Explorer Investor, Inc                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     0.2                
Less: funded commitments     0.0                
Total unfunded commitments     0.2                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 0.2                
Investment, Identifier [Axis]: Explorer Investor, Inc, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.15%         10.15% 10.15% 10.15% 10.15%
Total first lien senior secured loans [6],[7]     $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     0.9                
Investment, Identifier [Axis]: Extrahop Networks, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.0   5.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 13.0   5.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 13.0   $ 5.9                
Investment, Identifier [Axis]: Extrahop Networks, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.41% [1]   12.23% [2] 12.41% [1] 12.41% [1] 12.41% [1] 12.41% [1] 12.23% [2] 12.23% [2] 12.23% [2] 12.23% [2]
Total first lien senior secured loans $ 16.6 [3],[4]   $ 20.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 16.6 [3],[4]   20.2 [6],[7]                
Investment, Identifier [Axis]: Extrahop Networks, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.41%     12.41% 12.41% 12.41% 12.41%        
Total first lien senior secured loans [3],[4] $ 4.3                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 4.3                    
Investment, Identifier [Axis]: Extrahop Networks, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.41%     12.41% 12.41% 12.41% 12.41%        
Total first lien senior secured loans [3],[4] $ 3.9                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 3.8                    
Investment, Identifier [Axis]: FL Hawk Intermediate Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.5   0.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.5   0.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.5   0.5                
Investment, Identifier [Axis]: FM:Systems Group, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.5   1.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.5   $ 1.5                
Investment, Identifier [Axis]: FM:Systems Group, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.96% [1]   9.13% [2] 10.96% [1] 10.96% [1] 10.96% [1] 10.96% [1] 9.13% [2] 9.13% [2] 9.13% [2] 9.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: FM:Systems Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.60% [1]   10.96% [2] 10.60% [1] 10.60% [1] 10.60% [1] 10.60% [1] 10.96% [2] 10.96% [2] 10.96% [2] 10.96% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.6   9.6                
Less: funded commitments (0.5)   (0.5)                
Total unfunded commitments 9.1   9.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 9.1   9.1                
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.8 [4]   $ 31.2 [7]                
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.30% [1]   9.49% [2] 10.30% [1] 10.30% [1] 10.30% [1] 10.30% [1] 9.49% [2] 9.49% [2] 9.49% [2] 9.49% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [16]   0.0 [15]                
Investment, Identifier [Axis]: Faraday Buyer, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.7   4.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.7   4.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.7   $ 4.7                
Investment, Identifier [Axis]: Faraday Buyer, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.86% [1]   11.32% [2] 11.86% [1] 11.86% [1] 11.86% [1] 11.86% [1] 11.32% [2] 11.32% [2] 11.32% [2] 11.32% [2]
Total first lien senior secured loans $ 52.2 [3],[4]   $ 52.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 52.2 [3],[4]   50.6 [6],[7]                
Investment, Identifier [Axis]: Faraday&Future Inc., FF Inc., Faraday SPE, LLC and Faraday Future Intelligent Electric Inc., Warrant to purchase up to 633,008 shares of Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0 [7]                
Investment, Identifier [Axis]: Ferrellgas, L.P. and Ferrellgas Partners L.P., Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.9 [4]   $ 14.9                
Investment, Identifier [Axis]: Ferrellgas, L.P. and Ferrellgas Partners L.P., Senior preferred units                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.96% [1]   896.00% [2] 8.96% [1] 8.96% [1] 8.96% [1] 8.96% [1] 896.00% [2] 896.00% [2] 896.00% [2] 896.00% [2]
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 60.0   $ 60.0                
Investment, Identifier [Axis]: First Insight, Inc., Warrant to purchase shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0                    
Investment, Identifier [Axis]: First Insight, Inc., Warrant to purchase units of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.5   14.5                
Less: funded commitments (7.4)   (7.1)                
Total unfunded commitments 7.1   7.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 7.1   $ 7.4                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 29.6 [3],[4]   $ 29.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 29.6 [3],[4]   $ 29.6 [6],[7]                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 1.1 [3],[4]   $ 1.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.1 [3],[4]   $ 1.1 [6],[7]                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 6.5 [3],[4],[13]   $ 6.5 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.5 [3],[4],[13]   $ 6.5 [6],[7],[14]                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.50% [1]   11.50% [2] 12.50% [1] 12.50% [1] 12.50% [1] 12.50% [1] 11.50% [2] 11.50% [2] 11.50% [2] 11.50% [2]
Total first lien senior secured loans $ 0.8 [3],[4],[13]   $ 0.5 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.8 [3],[4],[13]   0.5 [6],[7],[14]                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.6 [4]   $ 1.5 [7]                
Investment, Identifier [Axis]: Florida Food Products, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.84% [1]   9.32% [2] 9.84% [1] 9.84% [1] 9.84% [1] 9.84% [1] 9.32% [2] 9.32% [2] 9.32% [2] 9.32% [2]
Total first lien senior secured loans $ 0.5 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.4 [3],[4]   $ 0.4 [6],[7]                
Investment, Identifier [Axis]: Florida Food Products, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.81% [1]   9.38% [2] 9.81% [1] 9.81% [1] 9.81% [1] 9.81% [1] 9.38% [2] 9.38% [2] 9.38% [2] 9.38% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.4 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Florida Food Products, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.84% [1]   12.38% [2] 12.84% [1] 12.84% [1] 12.84% [1] 12.84% [1] 12.38% [2] 12.38% [2] 12.38% [2] 12.38% [2]
Total first lien senior secured loans $ 71.8 [3],[4]   $ 71.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 67.5 [3],[4]   70.4 [6],[7]                
Investment, Identifier [Axis]: Forescout Technologies, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.2   14.2                
Less: funded commitments (0.1)   0.0                
Total unfunded commitments 14.1   14.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 14.1   $ 14.2                
Investment, Identifier [Axis]: Forescout Technologies, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon 14.66% [1]   14.23% [2] 14.66% [1] 14.66% [1] 14.66% [1] 14.66% [1] 14.23% [2] 14.23% [2] 14.23% [2] 14.23% [2]
Total first lien senior secured loans $ 24.3 [3],[4]   $ 23.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.3 [3],[4]   23.8 [6],[7]                
Investment, Identifier [Axis]: Forescout Technologies, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 12.9 [3],[4]   12.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.9 [3],[4]   $ 12.6 [6],[7]                
Investment, Identifier [Axis]: Forescout Technologies, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 13.44%     13.44% 13.44% 13.44% 13.44%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.1                    
Investment, Identifier [Axis]: Foundation Consumer Brands, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.38% [1]   10.15% [2] 10.38% [1] 10.38% [1] 10.38% [1] 10.38% [1] 10.15% [2] 10.15% [2] 10.15% [2] 10.15% [2]
Total first lien senior secured loans $ 13.6 [3],[4]   $ 12.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 13.6 [3],[4]   12.8 [6],[7]                
Investment, Identifier [Axis]: Foundation Risk Partners, Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 40.5   40.5                
Less: funded commitments 0.0   (8.6)                
Total unfunded commitments 40.5   31.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 40.5   $ 31.9                
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.68%         10.68% 10.68% 10.68% 10.68%
Total first lien senior secured loans [6],[7]     $ 112.6                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 111.5                
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.00%     11.00% 11.00% 11.00% 11.00%        
Total first lien senior secured loans [3] $ 104.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3] $ 102.3                    
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.00% [1]   10.68% [2] 11.00% [1] 11.00% [1] 11.00% [1] 11.00% [1] 10.68% [2] 10.68% [2] 10.68% [2] 10.68% [2]
Total first lien senior secured loans $ 30.2 [3],[4]   $ 30.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 29.6 [3],[4]   $ 30.0 [6],[7]                
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.68%         10.68% 10.68% 10.68% 10.68%
Total first lien senior secured loans [6],[7]     $ 1.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 1.1                
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.32%         10.32% 10.32% 10.32% 10.32%
Total first lien senior secured loans [6],[7]     $ 8.6                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     8.5                
Investment, Identifier [Axis]: GF Parent LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: GF Parent LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: GF Parent LLC, Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: GHX Ultimate Parent Corporation, Commerce Parent, Inc. and Commerce Topco, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 47.5   47.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 47.5   47.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 47.5   47.5                
Investment, Identifier [Axis]: GHX Ultimate Parent Corporation, Commerce Parent, Inc. and Commerce Topco, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 29.5 [4]   $ 27.8 [7]                
Investment, Identifier [Axis]: GHX Ultimate Parent Corporation, Commerce Parent, Inc. and Commerce Topco, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   11.48% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 114.0 [3],[4]   $ 114.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 112.9 [3],[4]   111.8 [6],[7]                
Investment, Identifier [Axis]: GI Ranger Intermediate LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.2   9.2                
Less: funded commitments (0.4)   (0.4)                
Total unfunded commitments 8.8   8.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 8.8   $ 8.8                
Investment, Identifier [Axis]: GI Ranger Intermediate LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.05% [1]   10.73% [2] 11.05% [1] 11.05% [1] 11.05% [1] 11.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 10.1 [3],[4]   $ 10.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.9 [3],[4]   $ 10.0 [6],[7]                
Investment, Identifier [Axis]: GI Ranger Intermediate LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.05% [1]   10.73% [2] 11.05% [1] 11.05% [1] 11.05% [1] 11.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 1.8 [3],[4]   $ 1.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.7 [3],[4]   $ 1.7 [6],[7]                
Investment, Identifier [Axis]: GI Ranger Intermediate LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.05% [1]   10.73% [2] 11.05% [1] 11.05% [1] 11.05% [1] 11.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.4 [3],[4]   0.4 [6],[7]                
Investment, Identifier [Axis]: GNZ Energy Bidco Limited and Galileo Co-investment Trust I                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.1   3.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.1   3.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.1   3.1                
Investment, Identifier [Axis]: GNZ Energy Bidco Limited and Galileo Co-investment Trust I, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.0 [4],[5]   $ 8.7 [7],[8]                
Investment, Identifier [Axis]: GNZ Energy Bidco Limited and Galileo Co-investment Trust I, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.69% [1]   10.65% [2] 11.69% [1] 11.69% [1] 11.69% [1] 11.69% [1] 10.65% [2] 10.65% [2] 10.65% [2] 10.65% [2]
Total first lien senior secured loans $ 30.4 [3],[4],[5]   $ 30.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 30.4 [3],[4],[5]   30.8 [6],[7],[8]                
Investment, Identifier [Axis]: GPM Investments, LLC and ARKO Corp., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 27.0   26.1                
Investment, Identifier [Axis]: GPM Investments, LLC and ARKO Corp., Warrant to purchase units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.7 [4]   1.9 [7]                
Investment, Identifier [Axis]: GSV PracticeTek Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.0 [4]   14.0 [7]                
Investment, Identifier [Axis]: Galway Borrower LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.8   9.8                
Less: funded commitments (2.3)   (0.4)                
Total unfunded commitments 7.5   9.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 7.5   $ 9.4                
Investment, Identifier [Axis]: Galway Borrower LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.15% [1]   9.98% [2] 10.15% [1] 10.15% [1] 10.15% [1] 10.15% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 34.1 [3],[4]   $ 34.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.1 [3],[4]   32.8 [6],[7]                
Investment, Identifier [Axis]: Galway Borrower LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.41%     10.41% 10.41% 10.41% 10.41%        
Total first lien senior secured loans $ 1.9 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [16]   0.0 [15]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.5                
Less: funded commitments (1.5)   (1.5)                
Total unfunded commitments 0.0   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.3 [4]   $ 1.4 [7]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.96% [1]   7.92% [2] 8.96% [1] 8.96% [1] 8.96% [1] 8.96% [1] 7.92% [2] 7.92% [2] 7.92% [2] 7.92% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [7]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.46% [1]   8.42% [2] 9.46% [1] 9.46% [1] 9.46% [1] 9.46% [1] 8.42% [2] 8.42% [2] 8.42% [2] 8.42% [2]
Total first lien senior secured loans $ 0.1 [4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.96% [1]   7.92% [2] 8.96% [1] 8.96% [1] 8.96% [1] 8.96% [1] 7.92% [2] 7.92% [2] 7.92% [2] 7.92% [2]
Total first lien senior secured loans $ 1.5 [4]   $ 1.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.5 [4]   $ 1.5 [7]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Second lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.25% [1]   11.24% [2] 12.25% [1] 12.25% [1] 12.25% [1] 12.25% [1] 11.24% [2] 11.24% [2] 11.24% [2] 11.24% [2]
Total first lien senior secured loans $ 32.4 [4]   $ 32.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 31.7 [4]   $ 31.7 [7]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.25% [1]   11.24% [2] 12.25% [1] 12.25% [1] 12.25% [1] 12.25% [1] 11.24% [2] 11.24% [2] 11.24% [2] 11.24% [2]
Total first lien senior secured loans $ 21.1 [3],[4]   $ 21.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 20.7 [3],[4]   $ 20.7 [6],[7]                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Second lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.25% [1]   11.24% [2] 12.25% [1] 12.25% [1] 12.25% [1] 12.25% [1] 11.24% [2] 11.24% [2] 11.24% [2] 11.24% [2]
Total first lien senior secured loans $ 7.5 [4]   $ 7.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.4 [4]   7.4 [7]                
Investment, Identifier [Axis]: Genomatica, Inc., Warrant to purchase 322,422 shares of Series D preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     $ 0.0                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.20% [1]   8.63% [2] 9.20% [1] 9.20% [1] 9.20% [1] 9.20% [1] 8.63% [2] 8.63% [2] 8.63% [2] 8.63% [2]
Total first lien senior secured loans $ 12.4 [3],[4],[11]   $ 12.1 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.7 [3],[4],[11]   $ 8.5 [6],[7],[12]                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.24% [1]   8.42% [2] 9.24% [1] 9.24% [1] 9.24% [1] 9.24% [1] 8.42% [2] 8.42% [2] 8.42% [2] 8.42% [2]
Total first lien senior secured loans $ 26.0 [3],[4],[11]   $ 25.7 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 18.1 [3],[4],[11]   $ 17.9 [6],[7],[12]                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   11.10% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 11.10% [2] 11.10% [2] 11.10% [2] 11.10% [2]
Total first lien senior secured loans $ 95.4 [3],[4]   $ 95.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 66.8 [3],[4]   71.6 [6],[7]                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., Warrant to purchase up to 1,926.57 units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0 [7]                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., Warrant to purchase up to 115,733 units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [4]   1.8 [7]                
Investment, Identifier [Axis]: Global Music Rights, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.3   4.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.3   4.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.3   $ 4.3                
Investment, Identifier [Axis]: Global Music Rights, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.23% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.5   33.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 22.5   33.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions (12.9)   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.6   $ 33.8                
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.22% [1]   11.80% [2] 12.22% [1] 12.22% [1] 12.22% [1] 12.22% [1] 11.80% [2] 11.80% [2] 11.80% [2] 11.80% [2]
Total first lien senior secured loans $ 27.6 [3],[4]   $ 17.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 26.2 [3],[4]   17.4 [6],[7]                
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC, Series E-1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 14.2 [4]   14.2 [7]                
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC, Warrant to purchase up to 43,154 shares of Series E-1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.0   5.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 5.0   $ 5.0                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.21% [1]   10.73% [2] 11.21% [1] 11.21% [1] 11.21% [1] 11.21% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.71% [1]   10.23% [2] 10.71% [1] 10.71% [1] 10.71% [1] 10.71% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.71% [1]   10.23% [2] 10.71% [1] 10.71% [1] 10.71% [1] 10.71% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.43% [1]   10.43% [2] 10.43% [1] 10.43% [1] 10.43% [1] 10.43% [1] 10.43% [2] 10.43% [2] 10.43% [2] 10.43% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 57.6   57.5                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 45.8 [4]   43.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 41.7 [4]   40.0 [7]                
Investment, Identifier [Axis]: GroundWorks, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9                    
Less: funded commitments 0.0                    
Total unfunded commitments 1.9                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.9                    
Investment, Identifier [Axis]: GroundWorks, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.36%     11.36% 11.36% 11.36% 11.36%        
Total first lien senior secured loans [3],[4] $ 10.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 9.7                    
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.1   $ 3.5                
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.53% [1]   8.07% [2] 8.53% [1] 8.53% [1] 8.53% [1] 8.53% [1] 8.07% [2] 8.07% [2] 8.07% [2] 8.07% [2]
Total first lien senior secured loans $ 26.3 [4],[11]   $ 26.4 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 22.4 [4],[11]   $ 23.3 [7],[12]                
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.84% [1]   8.38% [2] 8.84% [1] 8.84% [1] 8.84% [1] 8.84% [1] 8.38% [2] 8.38% [2] 8.38% [2] 8.38% [2]
Total first lien senior secured loans $ 3.3 [4],[11]   $ 3.3 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.9 [4],[11]   $ 3.0 [7],[12]                
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.84% [1]   9.38% [2] 9.84% [1] 9.84% [1] 9.84% [1] 9.84% [1] 9.38% [2] 9.38% [2] 9.38% [2] 9.38% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[11]   $ 0.1 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[11]   $ 0.1 [6],[7],[12]                
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.84% [1]   11.38% [2] 11.84% [1] 11.84% [1] 11.84% [1] 11.84% [1] 11.38% [2] 11.38% [2] 11.38% [2] 11.38% [2]
Total first lien senior secured loans $ 73.0 [4]   $ 73.0 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 62.1 [4]   62.8 [7]                
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.0   19.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 19.0   19.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 19.0   19.0                
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.1 [4]   $ 3.1 [7]                
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.42% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 60.4 [3],[4]   $ 60.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 60.4 [3],[4]   $ 60.5 [6],[7]                
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.41% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.41% [2] 11.41% [2] 11.41% [2] 11.41% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 7.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 7.8 [6],[7]                
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.42% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: HCI Equity, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   0.0                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: HCI Equity, LLC, Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [5],[11]   0.0 [8],[12]                
Investment, Identifier [Axis]: HGC Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 7.5   7.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.5   7.5                
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.7   14.8                
Less: funded commitments (2.8)   (2.8)                
Total unfunded commitments 8.9   12.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.9   12.0                
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.8 [4]   $ 2.2 [7]                
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.63% [1]   10.19% [2] 10.63% [1] 10.63% [1] 10.63% [1] 10.63% [1] 10.19% [2] 10.19% [2] 10.19% [2] 10.19% [2]
Total first lien senior secured loans $ 8.9 [3],[4]   $ 5.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.6 [3],[4]   $ 5.7 [6],[7]                
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.38% [1]   9.94% [2] 10.38% [1] 10.38% [1] 10.38% [1] 10.38% [1] 9.94% [2] 9.94% [2] 9.94% [2] 9.94% [2]
Total first lien senior secured loans $ 2.8 [3],[4]   $ 2.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.6 [3],[4]   $ 2.7 [6],[7]                
Investment, Identifier [Axis]: Halcon Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.55% [1]   12.20% [2] 12.55% [1] 12.55% [1] 12.55% [1] 12.55% [1] 12.20% [2] 12.20% [2] 12.20% [2] 12.20% [2]
Total first lien senior secured loans $ 13.1 [4]   $ 13.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 13.1 [4]   13.4 [7]                
Investment, Identifier [Axis]: Halex Holdings, Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   0.0                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Halex Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Hanger, Inc, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.95% [1]   10.43% [2] 10.95% [1] 10.95% [1] 10.95% [1] 10.95% [1] 10.43% [2] 10.43% [2] 10.43% [2] 10.43% [2]
Total first lien senior secured loans $ 54.2 [3],[4]   $ 54.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 52.3 [3],[4]   $ 53.2 [6],[7]                
Investment, Identifier [Axis]: Hanger, Inc, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.45% [1]   13.93% [2] 14.45% [1] 14.45% [1] 14.45% [1] 14.45% [1] 13.93% [2] 13.93% [2] 13.93% [2] 13.93% [2]
Total first lien senior secured loans $ 110.6 [3],[4]   $ 110.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 106.8 [3],[4]   106.8 [6],[7]                
Investment, Identifier [Axis]: Harvey Tool Company, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.5   28.5                
Less: funded commitments (5.2)   0.0                
Total unfunded commitments 23.3   28.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 23.3   $ 28.5                
Investment, Identifier [Axis]: Harvey Tool Company, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.68% [1]   10.64% [2] 10.68% [1] 10.68% [1] 10.68% [1] 10.68% [1] 10.64% [2] 10.64% [2] 10.64% [2] 10.64% [2]
Total first lien senior secured loans $ 1.1 [3],[4]   $ 1.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.1 [3],[4]   1.1 [6],[7]                
Investment, Identifier [Axis]: Harvey Tool Company, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.48%     10.48% 10.48% 10.48% 10.48%        
Total first lien senior secured loans [3],[4] $ 5.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 5.1                    
Investment, Identifier [Axis]: HealthEdge Software, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 33.5   36.2                
Less: funded commitments (2.7)   (0.3)                
Total unfunded commitments 30.8   35.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 30.8   $ 35.9                
Investment, Identifier [Axis]: HealthEdge Software, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.94% [1]   11.74% [2] 11.94% [1] 11.94% [1] 11.94% [1] 11.94% [1] 11.74% [2] 11.74% [2] 11.74% [2] 11.74% [2]
Total first lien senior secured loans $ 87.2 [3],[4]   $ 87.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 87.2 [3],[4]   87.2 [6],[7]                
Investment, Identifier [Axis]: HealthEdge Software, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.94%     11.94% 11.94% 11.94% 11.94%        
Total first lien senior secured loans [3],[4] $ 2.8                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 2.8                    
Investment, Identifier [Axis]: HealthEdge Software, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 14.00%     14.00% 14.00% 14.00% 14.00%        
Total first lien senior secured loans $ 2.4 [3],[4],[13]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [3],[4],[13]   0.0 [15]                
Investment, Identifier [Axis]: Heavy Construction Systems Specialists, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0   4.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.0   4.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.0   $ 4.0                
Investment, Identifier [Axis]: Heavy Construction Systems Specialists, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   95.4                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 2.2   7.1                
Capital structuring service fees 0.0   1.9                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 11.3   42.6                
Fair Value 223.1   209.6                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC, Class A1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 134.4   124.0                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC, Class A2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.2   $ 6.3                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 11.00% [1]   11.00% [2] 11.00% [1] 11.00% [1] 11.00% [1] 11.00% [1] 11.00% [2] 11.00% [2] 11.00% [2] 11.00% [2]
Total first lien senior secured loans $ 81.5 [3],[4]   $ 79.3 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 81.5 [3],[4]   79.3 [7]                
Investment, Identifier [Axis]: Helix Acquisition Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.00%     12.00% 12.00% 12.00% 12.00%        
Total first lien senior secured loans [3],[4] $ 12.6                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 12.2                    
Investment, Identifier [Axis]: Help/Systems Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 7.5   7.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.5   7.5                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 25.5   25.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 25.5   25.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 25.5   $ 25.5                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC 1                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.5                    
Less: funded commitments 0.0                    
Total unfunded commitments 13.5                    
Less: commitments substantially at discretion of the Company 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 13.5                    
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.05% [1]   10.73% [2] 11.05% [1] 11.05% [1] 11.05% [1] 11.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 22.7 [3],[4]   $ 22.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 22.5 [3],[4]   $ 22.6 [6],[7]                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   9.99% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 9.99% [2] 9.99% [2] 9.99% [2] 9.99% [2]
Total first lien senior secured loans $ 14.7 [3],[4]   $ 14.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.4 [3],[4]   $ 14.4 [6],[7]                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.05% [1]   10.73% [2] 11.05% [1] 11.05% [1] 11.05% [1] 11.05% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 12.2 [3],[4]   $ 12.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 12.1 [3],[4]   12.1 [6],[7]                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, Series A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.7 [4]   7.1 [7]                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, Series A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 125.3 [4]   112.9 [7]                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, Series C common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.8 [4]   $ 8.6 [7]                
Investment, Identifier [Axis]: HighTower Holding, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.75% [1]   675.00% [2] 6.75% [1] 6.75% [1] 6.75% [1] 6.75% [1] 675.00% [2] 675.00% [2] 675.00% [2] 675.00% [2]
Total first lien senior secured loans $ 8.1 [4],[5]   $ 8.1 [7],[8],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.8 [4],[5]   6.7 [7],[8],[12]                
Investment, Identifier [Axis]: Highline Aftermarket Acquisition, LLC, Highline Aftermarket SC Acquisition, Inc. and Highline PPC Blocker LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.5   9.5                
Less: funded commitments (0.3)   (1.1)                
Total unfunded commitments 9.2   8.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 9.2   8.4                
Investment, Identifier [Axis]: Highline Aftermarket Acquisition, LLC, Highline Aftermarket SC Acquisition, Inc. and Highline PPC Blocker LLC, Co-invest units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.8 [4]   $ 3.8 [7]                
Investment, Identifier [Axis]: Highline Aftermarket Acquisition, LLC, Highline Aftermarket SC Acquisition, Inc. and Highline PPC Blocker LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.34% [1]   8.88% [2] 9.34% [1] 9.34% [1] 9.34% [1] 9.34% [1] 8.88% [2] 8.88% [2] 8.88% [2] 8.88% [2]
Total first lien senior secured loans $ 9.8 [3],[4],[11]   $ 11.9 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.4 [3],[4],[11]   $ 10.9 [6],[7],[12]                
Investment, Identifier [Axis]: Highline Aftermarket Acquisition, LLC, Highline Aftermarket SC Acquisition, Inc. and Highline PPC Blocker LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.13%         8.13% 8.13% 8.13% 8.13%
Total first lien senior secured loans 0.0 [16]   $ 1.0 [7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [16]   $ 0.9 [7],[14]                
Investment, Identifier [Axis]: Highline Aftermarket Acquisition, LLC, Highline Aftermarket SC Acquisition, Inc. and Highline PPC Blocker LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.03% [1]   12.72% [2] 13.03% [1] 13.03% [1] 13.03% [1] 13.03% [1] 12.72% [2] 12.72% [2] 12.72% [2] 12.72% [2]
Total first lien senior secured loans $ 70.4 [3],[4]   $ 70.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 65.4 [3],[4]   64.0 [6],[7]                
Investment, Identifier [Axis]: Hometown Food Company                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9                
Less: funded commitments 0.0   (0.8)                
Total unfunded commitments 3.9   3.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.9   $ 3.1                
Investment, Identifier [Axis]: Hometown Food Company, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.39%         9.39% 9.39% 9.39% 9.39%
Total first lien senior secured loans [6],[7],[14]     $ 0.8                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7],[14]     $ 0.8                
Investment, Identifier [Axis]: Honor Technology, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.67% [1]   14.38% [2] 14.67% [1] 14.67% [1] 14.67% [1] 14.67% [1] 14.38% [2] 14.38% [2] 14.38% [2] 14.38% [2]
Total first lien senior secured loans $ 2.5 [3],[4]   $ 2.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.3 [3],[4]   2.3 [6],[7]                
Investment, Identifier [Axis]: Honor Technology, Inc., Warrant to purchase up to 133,333 units of Series D-2 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 0.0                    
Investment, Identifier [Axis]: Honor Technology, Inc., Warrant to purchase up to 133,333 units of series D-2 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     0.0                
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.6   22.6                
Less: funded commitments (9.4)   (9.4)                
Total unfunded commitments 13.2   13.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 13.2   13.2                
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.6 [4]   $ 5.5 [7]                
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.49% [1]   10.23% [2] 10.49% [1] 10.49% [1] 10.49% [1] 10.49% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 60.2 [3],[4]   $ 60.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 56.6 [3],[4]   $ 56.1 [6],[7]                
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.23% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 9.4 [3],[4]   $ 9.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 8.8 [3],[4]   8.7 [6],[7]                
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 102.0 [4]   99.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 85.7 [4]   82.6 [7]                
Investment, Identifier [Axis]: IQN Holding Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.8   6.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 6.8   6.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 6.8   $ 6.8                
Investment, Identifier [Axis]: IQN Holding Corp., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.38% [1]   9.65% [2] 10.38% [1] 10.38% [1] 10.38% [1] 10.38% [1] 9.65% [2] 9.65% [2] 9.65% [2] 9.65% [2]
Total first lien senior secured loans $ 0.5 [3],[4]   $ 23.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.5 [3],[4]   $ 23.3 [6],[7]                
Investment, Identifier [Axis]: IQN Holding Corp., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.71%         9.71% 9.71% 9.71% 9.71%
Total first lien senior secured loans [6],[7]     $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     0.4                
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, L.P, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 13.25%     13.25% 13.25% 13.25% 13.25%        
Total first lien senior secured loans $ 3.5 [3],[4],[13]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.5 [3],[4],[13]   0.0 [15]                
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.8                    
Less: funded commitments (3.7)                    
Total unfunded commitments 6.1                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 6.1                    
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 13.1 [4]   $ 12.5 [7]                
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.01% [1]   10.63% [2] 11.01% [1] 11.01% [1] 11.01% [1] 11.01% [1] 10.63% [2] 10.63% [2] 10.63% [2] 10.63% [2]
Total first lien senior secured loans $ 3.5 [3],[4]   $ 3.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.4 [3],[4]   3.5 [6],[7]                
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     9.8                
Less: funded commitments     (0.2)                
Total unfunded commitments     9.6                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     9.6                
Investment, Identifier [Axis]: ITI Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.6   5.7                
Less: funded commitments (7.6)   (2.0)                
Total unfunded commitments 0.0   3.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 3.7                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.58% [1]   10.08% [2] 10.58% [1] 10.58% [1] 10.58% [1] 10.58% [1] 10.08% [2] 10.08% [2] 10.08% [2] 10.08% [2]
Total first lien senior secured loans $ 34.9 [3],[4]   $ 35.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.9 [3],[4]   $ 34.7 [6],[7]                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.50% [1]   12.00% [2] 12.50% [1] 12.50% [1] 12.50% [1] 12.50% [1] 12.00% [2] 12.00% [2] 12.00% [2] 12.00% [2]
Total first lien senior secured loans $ 4.0 [3],[4]   $ 3.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.9 [3],[4]   $ 2.9 [6],[7]                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.50% [1]   9.88% [2] 12.50% [1] 12.50% [1] 12.50% [1] 12.50% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 3.0 [3]   $ 1.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.9 [3]   $ 1.1 [6],[7]                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured revolving loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.45% [1]   12.00% [2] 10.45% [1] 10.45% [1] 10.45% [1] 10.45% [1] 12.00% [2] 12.00% [2] 12.00% [2] 12.00% [2]
Total first lien senior secured loans $ 0.6 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.6 [3],[4]   0.8 [6],[7]                
Investment, Identifier [Axis]: IV Rollover Holdings, LLC, Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: IV Rollover Holdings, LLC, Class X units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.1 [4]   2.1 [7]                
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   3.9                
Sales (cost) 0.0   0.0                
Interest income 0.6   2.4                
Capital structuring service fees 0.0   0.7                
Dividend income 0.1   23.1                
Other income 0.2   0.5                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 3.5   (5.4)                
Fair Value 51.5   47.8                
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation, Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2   0.1                
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation, Class B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.5   $ 1.3                
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.00% [1]   14.00% [2] 14.00% [1] 14.00% [1] 14.00% [1] 14.00% [1] 14.00% [2] 14.00% [2] 14.00% [2] 14.00% [2]
Total first lien senior secured loans $ 16.6 [4]   $ 16.6 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 16.6 [4]   16.6 [7]                
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation, Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.2   $ 29.8                
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 14.30% [1]   13.98% [2] 14.30% [1] 14.30% [1] 14.30% [1] 14.30% [1] 13.98% [2] 13.98% [2] 13.98% [2] 13.98% [2]
Total first lien senior secured loans $ 116.9 [3],[4]   $ 102.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 99.4 [3],[4]   $ 92.4 [6],[7]                
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon 14.30% [1]   12.48% [2] 14.30% [1] 14.30% [1] 14.30% [1] 14.30% [1] 12.48% [2] 12.48% [2] 12.48% [2] 12.48% [2]
Total first lien senior secured loans $ 5.0 [3],[4]   $ 14.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.3 [3],[4]   $ 12.6 [6],[7]                
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon 14.30% [1]   12.48% [2] 14.30% [1] 14.30% [1] 14.30% [1] 14.30% [1] 12.48% [2] 12.48% [2] 12.48% [2] 12.48% [2]
Total first lien senior secured loans $ 1.3 [3],[4]   $ 5.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.1 [3],[4]   $ 4.5 [6],[7]                
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     13.98%         13.98% 13.98% 13.98% 13.98%
Total first lien senior secured loans [6],[7]     $ 1.3                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 1.1                
Investment, Identifier [Axis]: Imprivata, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.06% [1]   10.57% [2] 11.06% [1] 11.06% [1] 11.06% [1] 11.06% [1] 10.57% [2] 10.57% [2] 10.57% [2] 10.57% [2]
Total first lien senior secured loans $ 16.1 [3],[4]   $ 16.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 15.0 [3],[4]   15.1 [6],[7]                
Investment, Identifier [Axis]: Infinity Home Services HoldCo, Inc. and IHS Parent Holdings, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.4   13.0                
Less: funded commitments (0.4)   0.0                
Total unfunded commitments 8.0   13.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.0   13.0                
Investment, Identifier [Axis]: Infinity Home Services HoldCo, Inc. and IHS Parent Holdings, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.5 [4]   $ 9.5 [7]                
Investment, Identifier [Axis]: Infinity Home Services HoldCo, Inc. and IHS Parent Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.73% [1]   11.40% [2] 11.73% [1] 11.73% [1] 11.73% [1] 11.73% [1] 11.40% [2] 11.40% [2] 11.40% [2] 11.40% [2]
Total first lien senior secured loans $ 12.0 [3],[4]   $ 11.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.6 [3],[4]   $ 11.1 [6],[7]                
Investment, Identifier [Axis]: Infinity Home Services HoldCo, Inc. and IHS Parent Holdings, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 13.75%     13.75% 13.75% 13.75% 13.75%        
Total first lien senior secured loans [3],[4] $ 0.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.4                    
Investment, Identifier [Axis]: Inmar, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.84% [1]   12.38% [2] 12.84% [1] 12.84% [1] 12.84% [1] 12.84% [1] 12.38% [2] 12.38% [2] 12.38% [2] 12.38% [2]
Total first lien senior secured loans $ 28.3 [3],[4]   $ 28.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 27.7 [3],[4]   26.6 [6],[7]                
Investment, Identifier [Axis]: Inszone Mid, LLC and INSZ Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.8   17.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 15.8   17.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 15.8   $ 17.2                
Investment, Identifier [Axis]: Inszone Mid, LLC and INSZ Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.33% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.33% [2] 11.33% [2] 11.33% [2] 11.33% [2]
Total first lien senior secured loans $ 19.1 [3],[4]   $ 17.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 18.5 [3],[4]   17.1 [6],[7]                
Investment, Identifier [Axis]: Inszone Mid, LLC and INSZ Holdings, LLC, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8   1.7                
Investment, Identifier [Axis]: Ivy Hill Asset Management, L.P.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 283.1   1,544.2                
Redemptions (cost) 192.0   277.6                
Sales (cost) 0.0   0.0                
Interest income 12.7   22.5                
Capital structuring service fees 0.0   0.0                
Dividend income 57.0   205.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 3.3   (1.0)                
Fair Value 2,295.4   2,201.1                
Investment, Identifier [Axis]: Ivy Hill Asset Management, L.P., Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1,857.4 [5]   $ 1,701.1 [8]                
Investment, Identifier [Axis]: Ivy Hill Asset Management, L.P., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.55% [1]   11.01% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.01% [2] 11.01% [2] 11.01% [2] 11.01% [2]
Total first lien senior secured loans $ 438.0 [3],[5]   $ 500.0 [6],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 438.0 [3],[5]   500.0 [6],[8]                
Investment, Identifier [Axis]: JDC Healthcare Management, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.9   4.8                
Less: funded commitments (4.9)   (4.8)                
Total unfunded commitments 0.0   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: JDC Healthcare Management, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 41.4 [4],[9]   40.9 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.9 [4],[9]   22.1 [7],[10]                
Investment, Identifier [Axis]: JDC Healthcare Management, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 4.9 [4],[9]   4.8 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.3 [4],[9]   2.6 [7],[10]                
Investment, Identifier [Axis]: JWC/KI Holdings, LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.1 [4]   9.0 [7]                
Investment, Identifier [Axis]: Jenny C Acquisition, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 1.6 [4]   1.6 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.6 [4]   $ 1.6 [7]                
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.65%         10.65% 10.65% 10.65% 10.65%
Total first lien senior secured loans [6],[7]     $ 19.2                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     18.8                
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon [1] 11.14%     11.14% 11.14% 11.14% 11.14%        
Total first lien senior secured loans [3],[4] $ 19.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 19.2                    
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.21%     11.21% 11.21% 11.21% 11.21%        
Total first lien senior secured loans [3],[4] $ 4.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 4.0                    
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., Series A convertible preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.1 [4]   5.5 [7]                
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., Warrant to purchase up to 76,491 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.7 [4]   1.3 [7]                
Investment, Identifier [Axis]: Joyce Lane Capital LLC and Joyce Lane Financing SPV LLC (fka Ciena Capital LLC)                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0                
Redemptions (cost)     0.3                
Sales (cost)     0.0                
Interest income     0.1                
Capital structuring service fees     0.0                
Dividend income     0.0                
Other income     0.0                
Net realized gains (losses):     0.5                
Net unrealized gains (losses):     0.1                
Fair Value     0.0                
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.2   9.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.2   9.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.2   9.1                
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.9 [4]   $ 2.3 [7]                
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.16% [1]   9.73% [2] 10.16% [1] 10.16% [1] 10.16% [1] 10.16% [1] 9.73% [2] 9.73% [2] 9.73% [2] 9.73% [2]
Total first lien senior secured loans $ 50.3 [3],[4]   $ 50.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 50.3 [3],[4]   $ 50.4 [6],[7]                
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.16% [1]   9.73% [2] 10.16% [1] 10.16% [1] 10.16% [1] 10.16% [1] 9.73% [2] 9.73% [2] 9.73% [2] 9.73% [2]
Total first lien senior secured loans $ 3.2 [3],[4]   $ 2.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.2 [3],[4]   $ 2.3 [6],[7]                
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.01% [1]   9.54% [2] 10.01% [1] 10.01% [1] 10.01% [1] 10.01% [1] 9.54% [2] 9.54% [2] 9.54% [2] 9.54% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: KBHS Acquisition, LLC (d/b/a Alita Care, LLC)                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0                
Less: funded commitments (4.3)   (3.2)                
Total unfunded commitments 0.7   1.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.7   $ 1.8                
Investment, Identifier [Axis]: KBHS Acquisition, LLC (d/b/a Alita Care, LLC), First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon 9.85% [1]   9.72% [2] 9.85% [1] 9.85% [1] 9.85% [1] 9.85% [1] 9.72% [2] 9.72% [2] 9.72% [2] 9.72% [2]
Total first lien senior secured loans $ 4.2 [3],[4]   $ 3.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.1 [3],[4]   $ 3.1 [6],[7]                
Investment, Identifier [Axis]: KBHS Acquisition, LLC (d/b/a Alita Care, LLC), First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon [1] 12.00%     12.00% 12.00% 12.00% 12.00%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.1                    
Investment, Identifier [Axis]: KNPC HoldCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [1]   9.92% [2] 9.92% [1] 9.92% [1] 9.92% [1] 9.92% [1] 9.92% [2] 9.92% [2] 9.92% [2] 9.92% [2]
Total first lien senior secured loans $ 5.6 [3]   $ 5.6 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.5 [3]   $ 5.5 [6]                
Investment, Identifier [Axis]: KNPC HoldCo, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.42% [1]   11.42% [2] 11.42% [1] 11.42% [1] 11.42% [1] 11.42% [1] 11.42% [2] 11.42% [2] 11.42% [2] 11.42% [2]
Total first lien senior secured loans $ 1.3 [3],[4]   $ 1.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.3 [3],[4]   1.3 [6],[7]                
Investment, Identifier [Axis]: KPS Global LLC and Cool Group LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.4   $ 5.2                
Investment, Identifier [Axis]: KPS Global LLC and Cool Group LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   9.92% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 9.92% [2] 9.92% [2] 9.92% [2] 9.92% [2]
Total first lien senior secured loans $ 11.7 [3],[4]   $ 12.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.7 [3],[4]   $ 12.6 [6],[7]                
Investment, Identifier [Axis]: KPS Global LLC and Cool Group LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   9.92% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 9.92% [2] 9.92% [2] 9.92% [2] 9.92% [2]
Total first lien senior secured loans $ 3.1 [3],[4]   $ 3.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.1 [3],[4]   3.3 [6],[7]                
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 31.2   31.2                
Less: funded commitments (1.3)   0.0                
Total unfunded commitments 29.9   31.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 29.9   $ 31.2                
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.65% [1]   10.33% [2] 10.65% [1] 10.65% [1] 10.65% [1] 10.65% [1] 10.33% [2] 10.33% [2] 10.33% [2] 10.33% [2]
Total first lien senior secured loans $ 167.0 [3],[4]   $ 167.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 162.0 [3],[4]   162.0 [6],[7]                
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [16] 0.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [16] 0.0                    
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc., Perpetual preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] $ 40.0                    
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     $ 40.0                
Investment, Identifier [Axis]: Kellermeyer Bergensons Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.83% [1]   10.41% [2] 10.83% [1] 10.83% [1] 10.83% [1] 10.83% [1] 10.41% [2] 10.41% [2] 10.41% [2] 10.41% [2]
Total first lien senior secured loans $ 56.6 [3],[4]   $ 56.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 49.3 [3],[4]   $ 51.1 [6],[7]                
Investment, Identifier [Axis]: Kellermeyer Bergensons Services, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.83% [1]   10.41% [2] 10.83% [1] 10.83% [1] 10.83% [1] 10.83% [1] 10.41% [2] 10.41% [2] 10.41% [2] 10.41% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.9   8.9                
Less: funded commitments (0.2)   (0.2)                
Total unfunded commitments 8.7   8.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.7   8.7                
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.8 [4]   $ 7.0 [7]                
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.41% [1]   8.98% [2] 9.41% [1] 9.41% [1] 9.41% [1] 9.41% [1] 8.98% [2] 8.98% [2] 8.98% [2] 8.98% [2]
Total first lien senior secured loans $ 40.5 [3],[4]   $ 40.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 40.1 [3],[4]   39.8 [6],[7]                
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [16]   0.0 [15]                
Investment, Identifier [Axis]: KeyStone Sub-debt HoldCo, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]     60.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     58.8                
Investment, Identifier [Axis]: KeyStone Sub-debt HoldCo, LLC, Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]     8.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     7.8                
Investment, Identifier [Axis]: KeyStone Sub-debt HoldCo, LLC, Warrant to purchase up to 24.7581 Class C interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     8.3                
Investment, Identifier [Axis]: LJ Perimeter Buyer, Inc. and LJ Perimeter Co-Invest L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.33%     11.33% 11.33% 11.33% 11.33%        
Total first lien senior secured loans [3],[4] $ 36.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 35.8                    
Investment, Identifier [Axis]: LJ Perimeter Buyer, Inc. and LJ Perimeter Co-Invest L.P., Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 10.4                    
Investment, Identifier [Axis]: LJ Perimeter Buyer, Inc. and LJ Perimeter Co-Invest, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.6   10.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 9.6   10.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 9.6   $ 10.1                
Investment, Identifier [Axis]: LJ Perimeter Buyer, Inc. and LJ Perimeter Co-Invest, L.P. 1                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9                    
Less: funded commitments 0.0                    
Total unfunded commitments 1.9                    
Less: commitments substantially at discretion of the Company 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 1.9                    
Investment, Identifier [Axis]: LJ Perimeter Buyer, Inc. and LJ Perimeter Co-Invest, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.73%         10.73% 10.73% 10.73% 10.73%
Total first lien senior secured loans [6],[7]     $ 35.7                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     34.6                
Investment, Identifier [Axis]: LJ Perimeter Buyer, Inc. and LJ Perimeter Co-Invest, L.P., Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     9.7                
Investment, Identifier [Axis]: LJP Purchaser, Inc. and LJP Topco, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.4   4.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.4   4.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 4.4   4.4                
Investment, Identifier [Axis]: LJP Purchaser, Inc. and LJP Topco, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.2 [4]   $ 5.4 [7]                
Investment, Identifier [Axis]: LJP Purchaser, Inc. and LJP Topco, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.25% [1]   10.44% [2] 11.25% [1] 11.25% [1] 11.25% [1] 11.25% [1] 10.44% [2] 10.44% [2] 10.44% [2] 10.44% [2]
Total first lien senior secured loans $ 8.5 [3],[4]   $ 8.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 8.4 [3],[4]   8.3 [6],[7]                
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.6 [5]   $ 3.0 [8]                
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Senior subordinated loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   10.50% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [2] 10.50% [2] 10.50% [2] 10.50% [2]
Total first lien senior secured loans $ 3.0 [4],[5]   $ 3.0 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.9 [4],[5]   $ 3.0 [7],[8]                
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   10.50% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [2] 10.50% [2] 10.50% [2] 10.50% [2]
Total first lien senior secured loans $ 37.0 [4],[5]   $ 37.0 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 36.3 [4],[5]   36.6 [7],[8]                
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     3.9                
Less: funded commitments     0.0                
Total unfunded commitments     3.9                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 3.9                
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.59%         10.59% 10.59% 10.59% 10.59%
Total first lien senior secured loans [6],[7]     $ 21.2                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 21.6                
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.89%         10.89% 10.89% 10.89% 10.89%
Total first lien senior secured loans [6],[7]     $ 6.7                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 6.8                
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.42%         10.42% 10.42% 10.42% 10.42%
Total first lien senior secured loans [6],[7]     $ 6.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     6.2                
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     15.5                
Investment, Identifier [Axis]: LTG Acquisition, Inc., Class A membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 41.3   41.3                
Less: funded commitments (13.4)   (8.8)                
Total unfunded commitments 27.9   32.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 27.9   32.5                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.4 [4]   $ 4.5 [7]                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.78% [1]   9.98% [2] 10.78% [1] 10.78% [1] 10.78% [1] 10.78% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 40.2 [3],[4]   $ 23.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 38.2 [3],[4]   $ 22.7 [6],[7]                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.88% [1]   8.73% [2] 10.88% [1] 10.88% [1] 10.88% [1] 10.88% [1] 8.73% [2] 8.73% [2] 8.73% [2] 8.73% [2]
Total first lien senior secured loans $ 4.4 [3]   $ 16.7 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.2 [3]   $ 16.0 [6]                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.89% [1]   9.55% [2] 10.89% [1] 10.89% [1] 10.89% [1] 10.89% [1] 9.55% [2] 9.55% [2] 9.55% [2] 9.55% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 4.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 4.2 [6],[7]                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.73%         8.73% 8.73% 8.73% 8.73%
Total first lien senior secured loans [6],[7]     $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 0.1                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   12.25% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 12.25% [2] 12.25% [2] 12.25% [2] 12.25% [2]
Total first lien senior secured loans $ 13.4 [3],[4]   $ 8.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 12.7 [3],[4]   8.4 [6],[7]                
Investment, Identifier [Axis]: Largest Portfolio Company Investment | Senior Direct Lending Program                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 374.0   377.0                
Investment, Identifier [Axis]: LeanTaaS Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 48.6   54.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 48.6   54.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 48.6   $ 54.0                
Investment, Identifier [Axis]: LeanTaas Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.40% [1]   12.08% [2] 12.40% [1] 12.40% [1] 12.40% [1] 12.40% [1] 12.08% [2] 12.08% [2] 12.08% [2] 12.08% [2]
Total first lien senior secured loans $ 37.2 [3],[4]   $ 31.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 37.2 [3],[4]   31.2 [6],[7]                
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC and Leviathan Holdings, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   5.5                
Less: funded commitments (0.2)   (0.7)                
Total unfunded commitments 1.3   4.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.3   $ 4.8                
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC and Leviathan Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.54% [1]   12.54% [2] 12.54% [1] 12.54% [1] 12.54% [1] 12.54% [1] 12.54% [2] 12.54% [2] 12.54% [2] 12.54% [2]
Total first lien senior secured loans $ 16.2 [3],[4]   $ 16.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.7 [3],[4]   $ 15.8 [6],[7]                
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC and Leviathan Holdings, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.54% [1]   12.54% [2] 12.54% [1] 12.54% [1] 12.54% [1] 12.54% [1] 12.54% [2] 12.54% [2] 12.54% [2] 12.54% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.7 [6],[7]                
Investment, Identifier [Axis]: Leviathan Intermediate Holdco, LLC and Leviathan Holdings, L.P., Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.6   2.0                
Investment, Identifier [Axis]: Lew's Intermediate Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.3   2.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.3   $ 2.3                
Investment, Identifier [Axis]: Lew's Intermediate Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.89% [1]   9.40% [2] 9.89% [1] 9.89% [1] 9.89% [1] 9.89% [1] 9.40% [2] 9.40% [2] 9.40% [2] 9.40% [2]
Total first lien senior secured loans $ 1.0 [4]   $ 1.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.9 [4]   0.9 [6],[7]                
Investment, Identifier [Axis]: Lido Advisors, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.8   0.8                
Less: funded commitments (0.6)   (0.4)                
Total unfunded commitments 0.2   0.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.2   $ 0.4                
Investment, Identifier [Axis]: Lido Advisors, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.34% [1]   9.05% [2] 9.34% [1] 9.34% [1] 9.34% [1] 9.34% [1] 9.05% [2] 9.05% [2] 9.05% [2] 9.05% [2]
Total first lien senior secured loans $ 0.6 [3]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.6 [3]   0.4 [6],[7]                
Investment, Identifier [Axis]: LifeStyles Bidco Ltd., Lifestyles Intermediate Holdco Ltd. and LifeStyles Parent, L.P., Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4],[5]   $ 0.0 [7],[8]                
Investment, Identifier [Axis]: LifeStyles Bidco Ltd., Lifestyles Intermediate Holdco Ltd. and LifeStyles Parent, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.65% [1]   11.15% [2] 11.65% [1] 11.65% [1] 11.65% [1] 11.65% [1] 11.15% [2] 11.15% [2] 11.15% [2] 11.15% [2]
Total first lien senior secured loans $ 18.6 [3],[4],[5]   $ 18.6 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 18.2 [3],[4],[5]   18.2 [6],[7],[8]                
Investment, Identifier [Axis]: LifeStyles Bidco Ltd., Lifestyles Intermediate Holdco Ltd. and LifeStyles Parent, L.P., Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.3 [4],[5]   $ 3.2 [7],[8]                
Investment, Identifier [Axis]: Lifescan Global Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.75% [1]   9.74% [2] 10.75% [1] 10.75% [1] 10.75% [1] 10.75% [1] 9.74% [2] 9.74% [2] 9.74% [2] 9.74% [2]
Total first lien senior secured loans $ 14.0 [4],[11]   $ 14.3 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.4 [4],[11]   $ 10.3 [7]                
Investment, Identifier [Axis]: Lifescan Global Corporation, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.25% [1]   13.24% [2] 14.25% [1] 14.25% [1] 14.25% [1] 14.25% [1] 13.24% [2] 13.24% [2] 13.24% [2] 13.24% [2]
Total first lien senior secured loans $ 0.2 [4],[11]   $ 0.2 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [4],[11]   0.2 [7]                
Investment, Identifier [Axis]: Lower ACS, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 25.9   25.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 25.9   25.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 25.9   $ 25.9                
Investment, Identifier [Axis]: Lower ACS, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   10.13% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 0.8 [3],[4]   $ 5.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.8 [3],[4]   $ 5.4 [6],[7]                
Investment, Identifier [Axis]: MB Aerospace Holdings II Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.66% [1]   8.23% [2] 8.66% [1] 8.66% [1] 8.66% [1] 8.66% [1] 8.23% [2] 8.23% [2] 8.23% [2] 8.23% [2]
Total first lien senior secured loans $ 15.2 [3],[4],[11]   $ 14.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 13.4 [3],[4],[11]   $ 12.5 [6],[7]                
Investment, Identifier [Axis]: MB Aerospace Holdings II Corp., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.16% [1]   13.73% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.73% [2] 13.73% [2] 13.73% [2] 13.73% [2]
Total first lien senior secured loans $ 68.4 [3],[4]   $ 68.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 65.7 [3],[4]   $ 63.6 [6],[7]                
Investment, Identifier [Axis]: MB Aerospace Holdings II Corp., Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.16% [1]   13.73% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.73% [2] 13.73% [2] 13.73% [2] 13.73% [2]
Total first lien senior secured loans $ 23.6 [3],[4]   $ 23.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 22.7 [3],[4]   22.0 [6],[7]                
Investment, Identifier [Axis]: ME Equity LLC, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.3 [4]   4.5 [7]                
Investment, Identifier [Axis]: MRI Software LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.9   10.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 7.9   10.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 7.9   $ 10.6                
Investment, Identifier [Axis]: MRI Software LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.23% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 47.0 [3],[4]   $ 47.1 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 45.5 [3],[4]   $ 45.6 [6]                
Investment, Identifier [Axis]: MRI Software LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.23% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 20.0 [3],[4]   $ 17.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.4 [3],[4]   16.8 [6],[7]                
Investment, Identifier [Axis]: MailSouth, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 8.7 [4],[9]   8.7 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.5 [4],[9]   3.9 [7],[10]                
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.0   2.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.0   2.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 2.0   2.0                
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.3 [4]   3.6 [7]                
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P., Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4]   $ 0.0                
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.41% [1]   11.98% [2] 12.41% [1] 12.41% [1] 12.41% [1] 12.41% [1] 11.98% [2] 11.98% [2] 11.98% [2] 11.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 30.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   30.3 [6],[7]                
Investment, Identifier [Axis]: Management Consulting & Research LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     4.0                
Less: funded commitments     0.0                
Total unfunded commitments     4.0                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 4.0                
Investment, Identifier [Axis]: Management Consulting & Research LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.94%         10.94% 10.94% 10.94% 10.94%
Total first lien senior secured loans [6],[7]     $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     1.0                
Investment, Identifier [Axis]: Manna Pro Products, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.0   7.0                
Less: funded commitments (5.1)   (5.1)                
Total unfunded commitments 1.9   1.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.9   $ 1.9                
Investment, Identifier [Axis]: Manna Pro Products, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.81% [1]   10.14% [2] 10.81% [1] 10.81% [1] 10.81% [1] 10.81% [1] 10.14% [2] 10.14% [2] 10.14% [2] 10.14% [2]
Total first lien senior secured loans $ 5.1 [3],[4]   $ 5.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.6 [3],[4]   4.7 [6],[7]                
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.1 [4]   $ 10.2 [7]                
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.29% [1]   10.98% [2] 11.29% [1] 11.29% [1] 11.29% [1] 11.29% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 6.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4]   $ 6.5 [6],[7]                
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.29% [1]   10.91% [2] 11.29% [1] 11.29% [1] 11.29% [1] 11.29% [1] 10.91% [2] 10.91% [2] 10.91% [2] 10.91% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 2.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 2.5 [6],[7]                
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.16% [1]   10.94% [2] 11.16% [1] 11.16% [1] 11.16% [1] 11.16% [1] 10.94% [2] 10.94% [2] 10.94% [2] 10.94% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 2.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 2.1 [6],[7]                
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.28% [1]   10.98% [2] 11.28% [1] 11.28% [1] 11.28% [1] 11.28% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.3 [6],[7]                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.4   6.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 6.4   6.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 6.4   $ 6.9                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.80% [1]   10.80% [2] 11.80% [1] 11.80% [1] 11.80% [1] 11.80% [1] 10.80% [2] 10.80% [2] 10.80% [2] 10.80% [2]
Total first lien senior secured loans $ 1.2 [3],[4]   $ 0.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.2 [3],[4]   $ 0.7 [6],[7]                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.04% [1]   11.04% [2] 11.04% [1] 11.04% [1] 11.04% [1] 11.04% [1] 11.04% [2] 11.04% [2] 11.04% [2] 11.04% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.1 [4]   $ 2.6 [7]                
Investment, Identifier [Axis]: Maverick Acquisition, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.98% [2] 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 27.5 [3],[4]   $ 27.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.5 [3],[4]   25.4 [6],[7]                
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 32.9   32.9                
Less: funded commitments (19.0)   (7.3)                
Total unfunded commitments 13.9   25.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 13.9   25.6                
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP, Class A-1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.9 [4]   33.1 [7]                
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 8.65%     8.65% 8.65% 8.65% 8.65%        
Total first lien senior secured loans $ 9.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.0 [16]   $ 0.0 [15]                
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 7.65%     7.65% 7.65% 7.65% 7.65%        
Total first lien senior secured loans [4],[13] $ 2.6                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4],[13] 2.6                    
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP, Series A preferred stock                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     7.00%         7.00% 7.00% 7.00% 7.00%
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 78.3 [4]   $ 76.6 [7]                
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5                
Less: funded commitments 0.0   (1.9)                
Total unfunded commitments 4.5   2.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.5   $ 2.6                
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.60% [1]   9.43% [2] 10.60% [1] 10.60% [1] 10.60% [1] 10.60% [1] 9.43% [2] 9.43% [2] 9.43% [2] 9.43% [2]
Total first lien senior secured loans $ 84.5 [3],[4],[19]   $ 84.5 [6],[7],[20]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 84.5 [3],[4],[19]   $ 84.5 [6],[7],[20]                
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.60% [1]   10.14% [2] 10.60% [1] 10.60% [1] 10.60% [1] 10.60% [1] 10.14% [2] 10.14% [2] 10.14% [2] 10.14% [2]
Total first lien senior secured loans $ 5.5 [3],[4]   $ 5.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.5 [3],[4]   $ 5.5 [6],[7]                
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured loan, First Out Tranche                      
Schedule of Investments [Line Items]                      
Coupon 2.00%   2.00% 2.00% 2.00% 2.00% 2.00% 2.00% 2.00% 2.00% 2.00%
Total first lien senior secured loans $ 40.9   $ 40.9                
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.12%         10.12% 10.12% 10.12% 10.12%
Total first lien senior secured loans [6],[7]     $ 1.9                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 1.9                
Investment, Identifier [Axis]: McLaren Group Limited, Senior preference shares                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     12.50%         12.50% 12.50% 12.50% 12.50%
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 28.5 [4],[5]   $ 26.2 [7],[8]                
Investment, Identifier [Axis]: McLaren Group Limited, Warrant to purchase up to 13,776 units of ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [4],[5]   0.8 [7],[8]                
Investment, Identifier [Axis]: McLaren Group Limited, Warrant to purchase up to 49,181 units of ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.6 [4],[5]   2.8 [7],[8]                
Investment, Identifier [Axis]: Medline Borrower, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.9   6.9                
Less: funded commitments (0.1)   (0.2)                
Total unfunded commitments 6.8   6.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.8   6.7                
Investment, Identifier [Axis]: Medline Borrower, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [16]   0.0 [15]                
Investment, Identifier [Axis]: Miami Beckham United LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 96.7   94.7                
Investment, Identifier [Axis]: Micromeritics Instrument Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.1   4.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.1   $ 4.1                
Investment, Identifier [Axis]: Micromeritics Instrument Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.65% [1]   9.65% [2] 9.65% [1] 9.65% [1] 9.65% [1] 9.65% [1] 9.65% [2] 9.65% [2] 9.65% [2] 9.65% [2]
Total first lien senior secured loans $ 19.7 [3],[4]   $ 20.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.7 [3],[4]   20.7 [6],[7]                
Investment, Identifier [Axis]: Microstar Logistics LLC, Microstar Global Asset Management LLC, MStar Holding Corporation and Kegstar USA Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.3 [4]   $ 6.6 [7]                
Investment, Identifier [Axis]: Microstar Logistics LLC, Microstar Global Asset Management LLC, MStar Holding Corporation and Kegstar USA Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 15.86% [1]   15.58% [2] 15.86% [1] 15.86% [1] 15.86% [1] 15.86% [1] 15.58% [2] 15.58% [2] 15.58% [2] 15.58% [2]
Total first lien senior secured loans $ 163.7 [3],[4]   $ 159.3 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 163.7 [3],[4]   159.3 [6]                
Investment, Identifier [Axis]: Microstar Logistics LLC, Microstar Global Asset Management LLC, MStar Holding Corporation and Kegstar USA Inc., Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.9 [4]   2.6 [7]                
Investment, Identifier [Axis]: Mimecast Borrowerco, Inc. and Magnesium Co- Invest SCSp                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.1   15.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 15.1   15.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 15.1   $ 15.1                
Investment, Identifier [Axis]: Mimecast Borrowerco, Inc. and Magnesium Co- Invest SCSp 1                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.0                    
Less: funded commitments 0.0                    
Total unfunded commitments 1.0                    
Less: commitments substantially at discretion of the Company 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.0                    
Investment, Identifier [Axis]: Mimecast Borrowerco, Inc. and Magnesium Co-Invest SCSp, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.17% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.17% [2] 10.17% [2] 10.17% [2] 10.17% [2]
Total first lien senior secured loans $ 101.9 [3],[4],[5]   $ 102.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 98.8 [3],[4],[5]   $ 99.1 [6],[7],[8]                
Investment, Identifier [Axis]: Mimecast Borrowerco, Inc. and Magnesium Co-Invest SCSp, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.93% [1]   9.18% [2] 9.93% [1] 9.93% [1] 9.93% [1] 9.93% [1] 9.18% [2] 9.18% [2] 9.18% [2] 9.18% [2]
Total first lien senior secured loans $ 35.4 [3],[4],[5]   $ 34.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 34.4 [3],[4],[5]   33.7 [6],[7],[8]                
Investment, Identifier [Axis]: Mimecast Borrowerco, Inc. and Magnesium Co-Invest SCSp, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 40.0   39.4 [7],[8]                
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.4   31.3                
Less: funded commitments (2.0)   (4.0)                
Total unfunded commitments 26.4   27.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 26.4   $ 27.3                
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.52% [1]   9.88% [2] 10.52% [1] 10.52% [1] 10.52% [1] 10.52% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 35.4 [3],[4]   $ 32.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 33.6 [3],[4]   $ 30.9 [6],[7]                
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.30% [1]   9.88% [2] 10.30% [1] 10.30% [1] 10.30% [1] 10.30% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 4.0 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.9 [3],[4]   3.8 [6],[7],[14]                
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.7 [4]   $ 8.8 [7]                
Investment, Identifier [Axis]: Mitchell International, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.34% [1]   11.23% [2] 11.34% [1] 11.34% [1] 11.34% [1] 11.34% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 98.1 [3],[4],[11]   $ 98.1 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 84.8 [3],[4],[11]   81.0 [6],[7],[12]                
Investment, Identifier [Axis]: Monica Holdco (US) Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.6   3.6                
Less: funded commitments (3.6)   (2.4)                
Total unfunded commitments 0.0   1.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 1.2                
Investment, Identifier [Axis]: Monica Holdco (US) Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.48% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 2.6 [3],[4]   $ 2.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.5 [3],[4]   $ 2.5 [6],[7]                
Investment, Identifier [Axis]: Monica Holdco (US) Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.69% [1]   10.99% [2] 11.69% [1] 11.69% [1] 11.69% [1] 11.69% [1] 10.99% [2] 10.99% [2] 10.99% [2] 10.99% [2]
Total first lien senior secured loans $ 3.6 [3],[4]   $ 2.4 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.5 [3],[4]   2.3 [6],[7],[14]                
Investment, Identifier [Axis]: Monolith Brands Group, Inc., Series A-1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 15.5 [4]   15.5 [7]                
Investment, Identifier [Axis]: Moon Valley Nursery of Arizona Retail, LLC, Moon Valley Nursery Farm Holdings, LLC, Moon Valley Nursery RE Holdings LLC, and Stonecourt IV Partners, LP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 34.9 [3],[4]   42.9                
Investment, Identifier [Axis]: Moonraker AcquisitionCo LLC and Moonraker HoldCo LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.0   19.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 19.0   19.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 19.0   19.0                
Investment, Identifier [Axis]: Moonraker AcquisitionCo LLC and Moonraker HoldCo LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.5   $ 4.5                
Investment, Identifier [Axis]: Moonraker AcquisitionCo LLC and Moonraker HoldCo LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.63% [1]   10.32% [2] 10.63% [1] 10.63% [1] 10.63% [1] 10.63% [1] 10.32% [2] 10.32% [2] 10.32% [2] 10.32% [2]
Total first lien senior secured loans $ 25.0 [3],[4]   $ 25.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 25.0 [3],[4]   $ 24.6 [6],[7]                
Investment, Identifier [Axis]: Movati Athletic (Group) Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 10.91% [1]   10.18% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 4.7 [3],[4],[5]   $ 4.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.7 [3],[4],[5]   4.6 [6],[7],[8]                
Investment, Identifier [Axis]: Murchison Oil and Gas, LLC and Murchison Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.2   27.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 9.2   27.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.2   $ 27.5                
Investment, Identifier [Axis]: Murchison Oil and Gas, LLC and Murchison Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.55% [1]   13.08% [2] 13.55% [1] 13.55% [1] 13.55% [1] 13.55% [1] 13.08% [2] 13.08% [2] 13.08% [2] 13.08% [2]
Total first lien senior secured loans $ 93.8 [3],[4]   $ 75.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 93.8 [3],[4]   75.5 [6],[7]                
Investment, Identifier [Axis]: Murchison Oil and Gas, LLC and Murchison Holdings, LLC, Preferred units                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 8.00%     8.00% 8.00% 8.00% 8.00%        
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 45.7   45.9                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.0   3.0                
Less: funded commitments (0.6)   (0.6)                
Total unfunded commitments 2.4   2.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.4   $ 2.4                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.55% [1]   11.23% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 6.3 [3],[4]   $ 6.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.3 [3],[4]   $ 6.3 [6],[7]                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.55% [1]   11.23% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 2.3 [3],[4]   $ 2.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.3 [3],[4]   $ 2.3 [6],[7]                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.55% [1]   11.23% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 1.3 [3],[4]   $ 1.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.3 [3],[4]   $ 1.3 [6],[7]                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.55% [1]   11.23% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 0.6 [3],[4]   $ 0.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.6 [3],[4]   0.6 [6],[7]                
Investment, Identifier [Axis]: NCWS Intermediate, Inc. and NCWS Holdings LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.1   28.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 28.1   28.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 28.1   28.1                
Investment, Identifier [Axis]: NCWS Intermediate, Inc. and NCWS Holdings LP, Class A-2 common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 19.4 [4]   $ 18.5 [7]                
Investment, Identifier [Axis]: NCWS Intermediate, Inc. and NCWS Holdings LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.84% [1]   10.38% [2] 10.84% [1] 10.84% [1] 10.84% [1] 10.84% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 96.7 [3],[4]   $ 97.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 93.8 [3],[4]   $ 95.1 [6],[7]                
Investment, Identifier [Axis]: NCWS Intermediate, Inc. and NCWS Holdings LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.84% [1]   10.38% [2] 10.84% [1] 10.84% [1] 10.84% [1] 10.84% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.7   12.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 12.7   12.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 12.7   $ 12.7                
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.66% [1]   9.38% [2] 9.66% [1] 9.66% [1] 9.66% [1] 9.66% [1] 9.38% [2] 9.38% [2] 9.38% [2] 9.38% [2]
Total first lien senior secured loans $ 31.9 [3],[4]   $ 32.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 30.0 [3],[4]   $ 30.7 [6],[7]                
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.66% [1]   9.38% [2] 9.66% [1] 9.66% [1] 9.66% [1] 9.66% [1] 9.38% [2] 9.38% [2] 9.38% [2] 9.38% [2]
Total first lien senior secured loans $ 4.7 [3],[4]   $ 4.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.4 [3],[4]   4.5 [6],[7]                
Investment, Identifier [Axis]: NMN Holdings III Corp. and NMN Holdings LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.5   12.5                
Less: funded commitments (6.1)   (3.1)                
Total unfunded commitments 6.4   9.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 6.4   $ 9.4                
Investment, Identifier [Axis]: NMN Holdings III Corp. and NMN Holdings LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.59% [1]   8.13% [2] 8.59% [1] 8.59% [1] 8.59% [1] 8.59% [1] 8.13% [2] 8.13% [2] 8.13% [2] 8.13% [2]
Total first lien senior secured loans $ 5.3 [4],[13]   $ 2.3 [7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.9 [4],[13]   2.1 [7],[14]                
Investment, Identifier [Axis]: NMN Holdings III Corp. and NMN Holdings LP, Partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.3 [4]   2.0 [7]                
Investment, Identifier [Axis]: NSPC Intermediate Corp. and NSPC Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0                    
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.6 [4]   3.6 [7]                
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [4]   0.2 [7]                
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Senior preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.3 [4]   0.3 [7]                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Common stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Senior preferred series A-1 shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     46.5                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Series B preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Series B preferred stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: National College of Business and Technology Inc. & Leeds IV Advisors, Inc., Series C preferred stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: National Intergovernmental Purchasing Alliance Company                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.0   9.0                
Less: funded commitments 0.0   (1.2)                
Total unfunded commitments 9.0   7.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 9.0   $ 7.8                
Investment, Identifier [Axis]: National Intergovernmental Purchasing Alliance Company, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     7.12%         7.12% 7.12% 7.12% 7.12%
Total first lien senior secured loans [7]     $ 1.2                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     1.2                
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0                
Redemptions (cost)     131.0                
Sales (cost)     0.0                
Interest income     0.4                
Capital structuring service fees     0.0                
Dividend income     0.1                
Other income     0.0                
Net realized gains (losses):     19.0                
Net unrealized gains (losses):     (9.4)                
Fair Value     0.0                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   0.6                
Less: funded commitments (0.2)   (0.1)                
Total unfunded commitments 0.4   0.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.4   0.5                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V., Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.4 [4],[5]   $ 7.5 [7],[8]                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.99% [1]   8.66% [2] 6.99% [1] 6.99% [1] 6.99% [1] 6.99% [1] 8.66% [2] 8.66% [2] 8.66% [2] 8.66% [2]
Total first lien senior secured loans $ 4.9 [3],[4],[5]   $ 14.9 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.7 [3],[4],[5]   $ 14.6 [6],[7],[8]                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.08% [1]   6.11% [2] 9.08% [1] 9.08% [1] 9.08% [1] 9.08% [1] 6.11% [2] 6.11% [2] 6.11% [2] 6.11% [2]
Total first lien senior secured loans $ 14.8 [4],[5]   $ 4.8 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.5 [4],[5]   $ 4.7 [7],[8]                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.99% [1]   6.11% [2] 6.99% [1] 6.99% [1] 6.99% [1] 6.99% [1] 6.11% [2] 6.11% [2] 6.11% [2] 6.11% [2]
Total first lien senior secured loans $ 1.5 [4],[5]   $ 1.5 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.5 [4],[5]   $ 1.5 [7],[8]                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.09% [1]   8.66% [2] 9.09% [1] 9.09% [1] 9.09% [1] 9.09% [1] 8.66% [2] 8.66% [2] 8.66% [2] 8.66% [2]
Total first lien senior secured loans $ 0.2 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4],[5]   0.1 [6],[7],[8]                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.6   12.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 12.6   12.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 12.6   $ 12.6                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.74% [1]   8.82% [2] 9.74% [1] 9.74% [1] 9.74% [1] 9.74% [1] 8.82% [2] 8.82% [2] 8.82% [2] 8.82% [2]
Total first lien senior secured loans $ 99.3 [3],[4]   $ 99.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 89.1 [3],[4]   $ 88.4 [6],[7]                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.49% [1]   8.57% [2] 9.49% [1] 9.49% [1] 9.49% [1] 9.49% [1] 8.57% [2] 8.57% [2] 8.57% [2] 8.57% [2]
Total first lien senior secured loans $ 74.0 [3],[4]   $ 74.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 64.4 [3],[4]   $ 65.9 [6],[7]                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.27% [1]   6.25% [2] 7.27% [1] 7.27% [1] 7.27% [1] 7.27% [1] 6.25% [2] 6.25% [2] 6.25% [2] 6.25% [2]
Total first lien senior secured loans $ 16.4 [4]   $ 16.2 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 13.9 [4]   $ 14.4 [7]                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P., First lien senior secured notes                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.29% [1]   929.00% [2] 9.29% [1] 9.29% [1] 9.29% [1] 9.29% [1] 929.00% [2] 929.00% [2] 929.00% [2] 929.00% [2]
Total first lien senior secured loans $ 52.8 [4],[11]   $ 52.8 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 49.0 [4],[11]   49.8 [7],[12]                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.0 [4]   $ 4.0 [7]                
Investment, Identifier [Axis]: Neptune Bidco US Inc. and Elliott Metron Co-Investor Aggregator L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.49% [1]   13.57% [2] 14.49% [1] 14.49% [1] 14.49% [1] 14.49% [1] 13.57% [2] 13.57% [2] 13.57% [2] 13.57% [2]
Total first lien senior secured loans $ 221.3 [3],[4]   $ 221.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 201.4 [3],[4]   214.7 [6],[7]                
Investment, Identifier [Axis]: Nest Topco Borrower Inc., KKR Nest Co-Invest L.P., and NBLY 2021-1                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     119.1                
Less: funded commitments     0.0                
Total unfunded commitments     119.1                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     119.1                
Investment, Identifier [Axis]: Nest Topco Borrower Inc., KKR Nest Co-Invest L.P., and NBLY 2021-1, Limited partner interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.2 [4]   $ 10.2 [7]                
Investment, Identifier [Axis]: Nest Topco Borrower Inc., KKR Nest Co-Invest L.P., and NBLY 2021-1, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.46% [1]   13.26% [2] 13.46% [1] 13.46% [1] 13.46% [1] 13.46% [1] 13.26% [2] 13.26% [2] 13.26% [2] 13.26% [2]
Total first lien senior secured loans $ 119.1 [3],[4]   $ 119.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 117.9 [3],[4]   $ 117.9 [6],[7]                
Investment, Identifier [Axis]: New Era Cap, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.82% [1]   9.94% [2] 10.82% [1] 10.82% [1] 10.82% [1] 10.82% [1] 9.94% [2] 9.94% [2] 9.94% [2] 9.94% [2]
Total first lien senior secured loans $ 27.4 [3],[4]   $ 27.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 27.4 [3],[4]   27.8 [6],[7]                
Investment, Identifier [Axis]: Noble Aerospace, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.6   5.6                
Less: funded commitments (2.2)   (2.2)                
Total unfunded commitments 3.4   3.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.4   3.4                
Investment, Identifier [Axis]: Noble Aerospace, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [15]     0.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4],[16]   0.0 [15]                
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.1   8.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.1   8.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.1   8.1                
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.8 [4]   $ 2.9 [7]                
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.55% [1]   10.23% [2] 10.55% [1] 10.55% [1] 10.55% [1] 10.55% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 19.9 [3],[4]   $ 20.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 19.9 [3],[4]   $ 20.0 [6],[7]                
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.55% [1]   10.08% [2] 10.55% [1] 10.55% [1] 10.55% [1] 10.55% [1] 10.08% [2] 10.08% [2] 10.08% [2] 10.08% [2]
Total first lien senior secured loans $ 2.8 [3],[4]   $ 2.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.8 [3],[4]   2.9 [6],[7]                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P., Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 38.9 [4]   $ 38.8 [7]                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.68% [1]   10.18% [2] 10.68% [1] 10.68% [1] 10.68% [1] 10.68% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 47.4 [3],[4]   $ 47.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 47.4 [3],[4]   $ 47.5 [6],[7]                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.68% [1]   10.18% [2] 10.68% [1] 10.68% [1] 10.68% [1] 10.68% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 2.5 [3],[4]   $ 2.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.5 [3],[4]   $ 2.6 [6],[7]                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.68% [1]   10.18% [2] 10.68% [1] 10.68% [1] 10.68% [1] 10.68% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.68% [1]   10.18% [2] 10.68% [1] 10.68% [1] 10.68% [1] 10.68% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.25%     11.25% 11.25% 11.25% 11.25%        
Total first lien senior secured loans [4] $ 1.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 1.3                    
Investment, Identifier [Axis]: North Haven Fairway Buyer, LLC, Fairway Lawns, LLC and Command Pest Control, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.8   22.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 13.8   22.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 13.8   $ 22.5                
Investment, Identifier [Axis]: North Haven Fairway Buyer, LLC, Fairway Lawns, LLC and Command Pest Control, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.32% [1]   11.05% [2] 11.32% [1] 11.32% [1] 11.32% [1] 11.32% [1] 11.05% [2] 11.05% [2] 11.05% [2] 11.05% [2]
Total first lien senior secured loans $ 11.1 [3],[4]   $ 6.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.7 [3],[4]   6.2 [6],[7]                
Investment, Identifier [Axis]: North Haven Falcon Buyer, LLC and North Haven Falcon Holding Company, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     3.5                
Less: funded commitments     0.0                
Total unfunded commitments     3.5                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     3.5                
Investment, Identifier [Axis]: North Haven Falcon Buyer, LLC and North Haven Falcon Holding Company, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.1   $ 1.8                
Investment, Identifier [Axis]: North Haven Falcon Buyer, LLC and North Haven Falcon Holding Company, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 12.18% [1]   11.19% [2] 12.18% [1] 12.18% [1] 12.18% [1] 12.18% [1] 11.19% [2] 11.19% [2] 11.19% [2] 11.19% [2]
Total first lien senior secured loans $ 25.6 [3],[4]   $ 25.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 24.3 [3],[4]   23.5 [6],[7]                
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.3   5.1                
Less: funded commitments (1.0)   (0.8)                
Total unfunded commitments 3.3   4.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.3   $ 4.3                
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.35% [1]   9.90% [2] 10.35% [1] 10.35% [1] 10.35% [1] 10.35% [1] 9.90% [2] 9.90% [2] 9.90% [2] 9.90% [2]
Total first lien senior secured loans $ 7.7 [3],[4]   $ 6.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.4 [3],[4]   $ 6.7 [6],[7]                
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.37% [1]   9.92% [2] 10.37% [1] 10.37% [1] 10.37% [1] 10.37% [1] 9.92% [2] 9.92% [2] 9.92% [2] 9.92% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.0 [3],[4]   0.8 [6],[7]                
Investment, Identifier [Axis]: Novipax Buyer, L.L.C. and Novipax Parent Holding Company, L.L.C., Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 8.9 [4]   9.2 [7]                
Investment, Identifier [Axis]: Novipax Buyer, L.L.C. and Novipax Parent Holding Company, L.L.C., Class C units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Novipax Buyer, L.L.C. and Novipax Parent Holding Company, L.L.C., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.17% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.17% [2] 11.17% [2] 11.17% [2] 11.17% [2]
Total first lien senior secured loans $ 22.8 [3],[4]   $ 23.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 22.8 [3],[4]   $ 23.5 [6],[7]                
Investment, Identifier [Axis]: Novipax Buyer, L.L.C. and Novipax Parent Holding Company, L.L.C., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.17% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.17% [2] 11.17% [2] 11.17% [2] 11.17% [2]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 6.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4]   $ 6.3 [6],[7]                
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.03% [1]   10.02% [2] 10.03% [1] 10.03% [1] 10.03% [1] 10.03% [1] 10.02% [2] 10.02% [2] 10.02% [2] 10.02% [2]
Total first lien senior secured loans $ 25.7 [3],[4]   $ 25.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 25.7 [3],[4]   $ 25.9 [6],[7]                
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.02% [1]   10.02% [2] 10.02% [1] 10.02% [1] 10.02% [1] 10.02% [1] 10.02% [2] 10.02% [2] 10.02% [2] 10.02% [2]
Total first lien senior secured loans $ 15.2 [3],[4]   $ 15.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.2 [3],[4]   $ 15.2 [6],[7]                
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.03% [1]   10.02% [2] 10.03% [1] 10.03% [1] 10.03% [1] 10.03% [1] 10.02% [2] 10.02% [2] 10.02% [2] 10.02% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.05%     11.05% 11.05% 11.05% 11.05%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.1                    
Investment, Identifier [Axis]: OTG Management, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 13.1 [4]   13.1 [7]                
Investment, Identifier [Axis]: OTG Management, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: OTG Management, LLC, Warrant to purchase up to 7.73% of common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: OUTFRONT Media Inc., Series A convertible perpetual preferred stock                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.00% [1]   700.00% [2] 7.00% [1] 7.00% [1] 7.00% [1] 7.00% [1] 700.00% [2] 700.00% [2] 700.00% [2] 700.00% [2]
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 32.6 [4],[5]   $ 33.6 [7],[8]                
Investment, Identifier [Axis]: Offen, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     5.6                
Less: funded commitments     0.0                
Total unfunded commitments     5.6                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 5.6                
Investment, Identifier [Axis]: Offen, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [1]   8.51% [2] 9.92% [1] 9.92% [1] 9.92% [1] 9.92% [1] 8.51% [2] 8.51% [2] 8.51% [2] 8.51% [2]
Total first lien senior secured loans $ 0.1 [4]   $ 1.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [4]   1.4 [7]                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P. and Asclepius Hodlings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 1.3   8.3                
Redemptions (cost) 0.1   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   3.2                
Capital structuring service fees 0.0   0.3                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (8.5)   (11.7)                
Fair Value 37.5   44.7                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.2   1.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.2   1.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions (0.5)   (1.6)                
Total net adjusted unfunded revolving and delayed draw loan commitments 4.7   0.0                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 52.2 [3]   50.9 [10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 31.4 [3]   38.1 [10]                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 10.2 [3],[4]   8.7 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.1 [3],[4]   6.6 [7],[10]                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: OneDigital Borrower LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5                
Less: funded commitments (0.4)   (0.4)                
Total unfunded commitments 7.1   7.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.1   7.1                
Investment, Identifier [Axis]: OneDigital Borrower LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [15]     0.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4],[16]   0.0 [15]                
Investment, Identifier [Axis]: Opal Fuels LLC and Opal Fuels Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 21.3 [5],[11]   22.3 [8],[12]                
Investment, Identifier [Axis]: Opal Fuels LLC and Opal Fuels Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 29.1 [5]   28.5 [8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 29.1 [5]   $ 28.5 [8]                
Investment, Identifier [Axis]: OpenMarket Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.41% [1]   10.98% 11.41% [1] 11.41% [1] 11.41% [1] 11.41% [1] 10.98% 10.98% 10.98% 10.98%
Total first lien senior secured loans $ 14.9 [3],[4],[5]   $ 51.6 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.8 [3],[4],[5]   $ 51.1 [6],[7],[8]                
Investment, Identifier [Axis]: Osmose Utilities Services, Inc. and Pine Intermediate Holding LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   11.13% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 55.3 [3],[4]   $ 55.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 51.9 [3],[4]   51.4 [6],[7]                
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment II, L.P.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.1                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 1.1   4.2                
Fair Value 16.6   15.5                
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment II, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 16.6 [4],[5]   15.5 [7],[8]                
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment, L.P.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   (0.6)                
Fair Value 0.7   0.7                
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment, L.P. and PCG-Ares Sidecar Investment II, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 50.0   50.0                
Less: funded commitments (12.4)   (12.5)                
Total unfunded commitments 37.6   37.5                
Less: commitments substantially at discretion of the Company (37.6)   (37.5)                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.0   0.0                
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [5]   0.7 [8]                
Investment, Identifier [Axis]: PDDS HoldCo, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.1   2.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.1   2.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.1   $ 2.1                
Investment, Identifier [Axis]: PDDS Holdco, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.54% [1]   12.30% [2] 12.54% [1] 12.54% [1] 12.54% [1] 12.54% [1] 12.30% [2] 12.30% [2] 12.30% [2] 12.30% [2]
Total first lien senior secured loans $ 9.5 [3],[4]   $ 9.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.5 [3],[4]   9.2 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.6   7.6                
Less: funded commitments (3.8)   (6.1)                
Total unfunded commitments 3.8   1.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.8   1.5                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.5 [4]   $ 2.7 [7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.30% [1]   8.73% [2] 9.30% [1] 9.30% [1] 9.30% [1] 9.30% [1] 8.73% [2] 8.73% [2] 8.73% [2] 8.73% [2]
Total first lien senior secured loans $ 52.8 [3],[4]   $ 52.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 52.2 [3],[4]   $ 51.9 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.29% [1]   8.82% [2] 9.29% [1] 9.29% [1] 9.29% [1] 9.29% [1] 8.82% [2] 8.82% [2] 8.82% [2] 8.82% [2]
Total first lien senior secured loans $ 3.8 [3],[4]   $ 6.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.8 [3],[4]   $ 6.0 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Second lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.41% [1]   13.18% [2] 13.41% [1] 13.41% [1] 13.41% [1] 13.41% [1] 13.18% [2] 13.18% [2] 13.18% [2] 13.18% [2]
Total first lien senior secured loans $ 70.1 [3],[4]   $ 70.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 69.4 [3],[4]   $ 68.7 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.41% [1]   13.18% [2] 13.41% [1] 13.41% [1] 13.41% [1] 13.41% [1] 13.18% [2] 13.18% [2] 13.18% [2] 13.18% [2]
Total first lien senior secured loans $ 8.7 [3],[4]   $ 8.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.7 [3],[4]   $ 8.6 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Second lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.41% [1]   13.18% [2] 13.41% [1] 13.41% [1] 13.41% [1] 13.41% [1] 13.18% [2] 13.18% [2] 13.18% [2] 13.18% [2]
Total first lien senior secured loans $ 8.3 [3],[4]   $ 8.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.2 [3],[4]   $ 8.1 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Second lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.41% [1]   13.18% [2] 13.41% [1] 13.41% [1] 13.41% [1] 13.41% [1] 13.18% [2] 13.18% [2] 13.18% [2] 13.18% [2]
Total first lien senior secured loans $ 7.2 [3],[4]   $ 7.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 7.1 [3],[4]   7.1 [6],[7]                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 23.3 [4]   21.2 [7]                
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC, Common unit                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.5 [4]   $ 8.3 [7]                
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.16% [1]   10.73% [2] 11.16% [1] 11.16% [1] 11.16% [1] 11.16% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 14.9 [3],[4]   $ 14.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.9 [3],[4]   $ 14.9 [6],[7]                
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.16% [1]   10.73% [2] 11.16% [1] 11.16% [1] 11.16% [1] 11.16% [1] 10.73% [2] 10.73% [2] 10.73% [2] 10.73% [2]
Total first lien senior secured loans $ 4.5 [3],[4]   $ 4.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.5 [3],[4]   4.5 [6],[7]                
Investment, Identifier [Axis]: PS Operating Company LLC and PS Op Holdings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   6.3                
Redemptions (cost) 0.0   4.6                
Sales (cost) 0.0   0.0                
Interest income 0.5   1.5                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (0.9)   1.0                
Fair Value 26.9   27.7                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.9   5.9                
Less: funded commitments (4.5)   (4.5)                
Total unfunded commitments 1.4   1.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 1.4   1.4                
Investment, Identifier [Axis]: Partnership Capital Growth Investors III, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.0 [4],[5],[11]   3.9 [7],[8],[12]                
Investment, Identifier [Axis]: Pathway Vet Alliance LLC and Jedi Group Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9   1.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.9   1.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 1.9   1.9                
Investment, Identifier [Axis]: Pathway Vet Alliance LLC and Jedi Group Holdings LLC, Class R common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.6 [4]   $ 5.5 [7]                
Investment, Identifier [Axis]: Pathway Vet Alliance LLC and Jedi Group Holdings LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.59% [1]   12.13% [2] 12.59% [1] 12.59% [1] 12.59% [1] 12.59% [1] 12.13% [2] 12.13% [2] 12.13% [2] 12.13% [2]
Total first lien senior secured loans $ 76.3 [3],[4]   $ 76.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 66.4 [3],[4]   65.6 [6],[7]                
Investment, Identifier [Axis]: Patriot Growth Insurance Services, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.2   2.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.2   2.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.2   $ 2.2                
Investment, Identifier [Axis]: Patriot Growth Insurance Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.35% [1]   8.87% [2] 10.35% [1] 10.35% [1] 10.35% [1] 10.35% [1] 8.87% [2] 8.87% [2] 8.87% [2] 8.87% [2]
Total first lien senior secured loans $ 15.9 [3],[4]   $ 16.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 15.3 [3],[4]   15.5 [6],[7]                
Investment, Identifier [Axis]: PayNearMe, Inc., Warrant to purchase up to 195,726 shares of Series E preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value     0.0                
Investment, Identifier [Axis]: Paya, Inc and GTCR-Ultra Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     4.5                
Less: funded commitments     0.0                
Total unfunded commitments     4.5                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     4.5                
Investment, Identifier [Axis]: Paya, Inc and GTCR-Ultra Holdings LLC, Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     2.6                
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.6   20.6                
Less: funded commitments (3.9)   0.0                
Total unfunded commitments 7.7   20.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.7   20.6                
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.7   $ 14.3                
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.87% [1]   10.48% [2] 10.87% [1] 10.87% [1] 10.87% [1] 10.87% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 13.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4]   $ 13.7 [6],[7]                
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.48% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   9.98% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC, First lien senior secured revolving                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.41%     10.41% 10.41% 10.41% 10.41%        
Total first lien senior secured loans [3],[4] $ 3.9                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 3.9                    
Investment, Identifier [Axis]: Pelican Products, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.3   2.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.3   $ 2.3                
Investment, Identifier [Axis]: Pelican Products, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.91% [1]   12.20% [2] 12.91% [1] 12.91% [1] 12.91% [1] 12.91% [1] 12.20% [2] 12.20% [2] 12.20% [2] 12.20% [2]
Total first lien senior secured loans $ 60.0 [3],[4]   $ 60.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 54.6 [3],[4]   55.8 [6],[7]                
Investment, Identifier [Axis]: People Corporation                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 20.2   20.6                
Less: funded commitments (1.3)   (1.3)                
Total unfunded commitments 18.9   19.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 18.9   $ 19.3                
Investment, Identifier [Axis]: People Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.24% [1]   10.91% [2] 11.24% [1] 11.24% [1] 11.24% [1] 11.24% [1] 10.91% [2] 10.91% [2] 10.91% [2] 10.91% [2]
Total first lien senior secured loans $ 26.1 [3],[4],[5]   $ 40.9 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 26.1 [3],[4],[5]   $ 40.5 [6],[7],[8]                
Investment, Identifier [Axis]: People Corporation, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.24% [1]   10.91% [2] 11.24% [1] 11.24% [1] 11.24% [1] 11.24% [1] 10.91% [2] 10.91% [2] 10.91% [2] 10.91% [2]
Total first lien senior secured loans $ 12.7 [3],[4],[5]   $ 12.8 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.7 [3],[4],[5]   $ 12.6 [6],[7],[8]                
Investment, Identifier [Axis]: People Corporation, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.49% [1]   10.17% [2] 10.49% [1] 10.49% [1] 10.49% [1] 10.49% [1] 10.17% [2] 10.17% [2] 10.17% [2] 10.17% [2]
Total first lien senior secured loans $ 8.5 [3],[4],[5]   $ 8.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.3 [3],[4],[5]   $ 7.8 [6],[7],[8]                
Investment, Identifier [Axis]: People Corporation, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.28% [1]   10.99% [2] 11.28% [1] 11.28% [1] 11.28% [1] 11.28% [1] 10.99% [2] 10.99% [2] 10.99% [2] 10.99% [2]
Total first lien senior secured loans $ 1.3 [3],[4],[5]   $ 1.3 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.3 [3],[4],[5]   1.3 [6],[7],[8]                
Investment, Identifier [Axis]: Perforce Software, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.5   0.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.5   0.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.5   $ 0.5                
Investment, Identifier [Axis]: PerkinElmer U.S. LLC and NM Polaris Co-Invest, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.86%     11.86% 11.86% 11.86% 11.86%        
Total first lien senior secured loans [3],[4] $ 17.5                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 17.0                    
Investment, Identifier [Axis]: PerkinElmer U.S. LLC and NM Polaris Co-Invest, L.P., Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 9.8                    
Investment, Identifier [Axis]: PestCo Holdings, LLC and PestCo, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9                    
Less: funded commitments 0.0                    
Total unfunded commitments 0.9                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 0.9                    
Investment, Identifier [Axis]: PestCo Holdings, LLC and PestCo, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.7                    
Investment, Identifier [Axis]: PestCo Holdings, LLC and PestCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.86%     11.86% 11.86% 11.86% 11.86%        
Total first lien senior secured loans [3],[4] $ 1.7                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 1.6                    
Investment, Identifier [Axis]: PetVet Care Centers, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.81% [1]   9.38% [2] 9.81% [1] 9.81% [1] 9.81% [1] 9.81% [1] 9.38% [2] 9.38% [2] 9.38% [2] 9.38% [2]
Total first lien senior secured loans $ 5.3 [3],[4]   $ 5.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.1 [3],[4]   5.0 [6],[7]                
Investment, Identifier [Axis]: Petroleum Service Group LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 17.5   17.5                
Less: funded commitments (3.5)   (4.4)                
Total unfunded commitments 14.0   13.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 14.0   $ 13.1                
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.83% [1]   10.42% [2] 10.83% [1] 10.83% [1] 10.83% [1] 10.83% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 34.4 [3],[4]   $ 34.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 34.4 [3],[4]   $ 34.5 [6],[7]                
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.99% [1]   10.72% [2] 10.99% [1] 10.99% [1] 10.99% [1] 10.99% [1] 10.72% [2] 10.72% [2] 10.72% [2] 10.72% [2]
Total first lien senior secured loans $ 11.4 [3],[4]   $ 11.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.4 [3],[4]   $ 11.6 [6],[7]                
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 9.75%     9.75% 9.75% 9.75% 9.75%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.1                    
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.06% [1]   9.71% [2] 11.06% [1] 11.06% [1] 11.06% [1] 11.06% [1] 9.71% [2] 9.71% [2] 9.71% [2] 9.71% [2]
Total first lien senior secured loans $ 1.6 [3],[4],[13]   $ 2.5 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.6 [3],[4],[13]   2.5 [6],[7],[14]                
Investment, Identifier [Axis]: Petrus Buyer, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.7   2.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.7   2.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.7   $ 2.7                
Investment, Identifier [Axis]: Petrus Buyer, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.18%   10.70% [2] 11.18% 11.18% 11.18% 11.18% 10.70% [2] 10.70% [2] 10.70% [2] 10.70% [2]
Total first lien senior secured loans $ 5.1   $ 5.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.9   4.9 [6],[7]                
Investment, Identifier [Axis]: Petvisor Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 31.8   37.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 31.8   37.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 31.8   $ 37.6                
Investment, Identifier [Axis]: Petvisor Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.69% [1]   10.21% [2] 10.69% [1] 10.69% [1] 10.69% [1] 10.69% [1] 10.21% [2] 10.21% [2] 10.21% [2] 10.21% [2]
Total first lien senior secured loans $ 6.0 [3],[4]   $ 21.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.0 [3],[4]   21.5 [6],[7]                
Investment, Identifier [Axis]: Ping Identity Holding Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2   0.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.2   0.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.2   $ 0.2                
Investment, Identifier [Axis]: Ping Identity Holding Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.76% [1]   11.32% [2] 11.76% [1] 11.76% [1] 11.76% [1] 11.76% [1] 11.32% [2] 11.32% [2] 11.32% [2] 11.32% [2]
Total first lien senior secured loans $ 11.3 [3],[4]   $ 11.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 11.0 [3],[4]   11.0 [6],[7]                
Investment, Identifier [Axis]: Piper Jaffray Merchant Banking Fund I, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.5 [5],[11]   0.5 [8],[12]                
Investment, Identifier [Axis]: Plaskolite PPC Intermediate II LLC and Plaskolite PPC Blocker LLC, Co-Invest units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.4 [4]   $ 0.5 [7]                
Investment, Identifier [Axis]: Plaskolite PPC Intermediate II LLC and Plaskolite PPC Blocker LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.83% [1]   8.41% [2] 8.83% [1] 8.83% [1] 8.83% [1] 8.83% [1] 8.41% [2] 8.41% [2] 8.41% [2] 8.41% [2]
Total first lien senior secured loans $ 22.5 [3],[4]   $ 22.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 19.9 [3],[4]   $ 20.1 [6],[7]                
Investment, Identifier [Axis]: Plaskolite PPC Intermediate II LLC and Plaskolite PPC Blocker LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.11% [1]   11.98% [2] 12.11% [1] 12.11% [1] 12.11% [1] 12.11% [1] 11.98% [2] 11.98% [2] 11.98% [2] 11.98% [2]
Total first lien senior secured loans $ 55.0 [3],[4]   $ 55.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 48.9 [3],[4]   48.9 [6],[7]                
Investment, Identifier [Axis]: Pluralsight, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.3   0.3                
Less: funded commitments (0.2)   (0.2)                
Total unfunded commitments 0.1   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.1   $ 0.1                
Investment, Identifier [Axis]: Pluralsight, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.78% [1]   11.83% [2] 12.78% [1] 12.78% [1] 12.78% [1] 12.78% [1] 11.83% [2] 11.83% [2] 11.83% [2] 11.83% [2]
Total first lien senior secured loans $ 106.2 [3],[4]   $ 106.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 104.0 [3],[4]   $ 104.0 [6],[7]                
Investment, Identifier [Axis]: Pluralsight, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.78% [1]   12.36% [2] 12.78% [1] 12.78% [1] 12.78% [1] 12.78% [1] 12.36% [2] 12.36% [2] 12.36% [2] 12.36% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Polymer Solutions Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.92%         8.92% 8.92% 8.92% 8.92%
Total first lien senior secured loans [6],[7]     $ 0.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     0.0                
Investment, Identifier [Axis]: Poplicus Incorporated, Warrant to purchase up to 2,402,991 shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: PosiGen, Inc., Warrant to purchase up to 1,112,022 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: PosiGen, Inc., Warrant to purchase up to 101,555 shares of series D-1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: Potomac Intermediate Holdings II LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   6.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (9.3)   (42.4)                
Fair Value 134.0   143.2                
Investment, Identifier [Axis]: Potomac Intermediate Holdings II LLC, Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 134.0   143.2                
Investment, Identifier [Axis]: Precinmac (US) Holdings Inc., Trimaster Manufacturing Inc. and Blade Group Holdings, LP., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 27.9 [4]   $ 26.5 [7]                
Investment, Identifier [Axis]: Precinmac (US) Holdings Inc., Trimaster Manufacturing Inc. and Blade Group Holdings, LP., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.42% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 11.6 [3],[4],[5]   $ 11.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.4 [3],[4],[5]   $ 11.4 [6],[7],[8]                
Investment, Identifier [Axis]: Precinmac (US) Holdings Inc., Trimaster Manufacturing Inc. and Blade Group Holdings, LP., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.42% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.42% [2] 10.42% [2] 10.42% [2] 10.42% [2]
Total first lien senior secured loans $ 4.0 [3],[4],[5]   $ 4.0 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.9 [3],[4],[5]   3.9 [6],[7],[8]                
Investment, Identifier [Axis]: Precision Concepts International LLC and Precision Concepts Canada Corporation                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.2   19.2                
Less: funded commitments (8.2)   (6.2)                
Total unfunded commitments 11.0   13.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 11.0   $ 13.0                
Investment, Identifier [Axis]: Precision Concepts International LLC and Precision Concepts Canada Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   10.18% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 14.6 [3],[4],[5]   $ 14.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.6 [3],[4],[5]   $ 14.7 [6],[7],[8]                
Investment, Identifier [Axis]: Precision Concepts International LLC and Precision Concepts Canada Corporation, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.75% [1]   10.43% [2] 10.75% [1] 10.75% [1] 10.75% [1] 10.75% [1] 10.43% [2] 10.43% [2] 10.43% [2] 10.43% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investment, Identifier [Axis]: Precision Concepts International LLC and Precision Concepts Canada Corporation, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [1]   10.18% [2] 10.50% [1] 10.50% [1] 10.50% [1] 10.50% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 0.1 [6],[7],[8]                
Investment, Identifier [Axis]: Precision Concepts International LLC and Precision Concepts Canada Corporation, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.48% [1]   10.18% [2] 10.48% [1] 10.48% [1] 10.48% [1] 10.48% [1] 10.18% [2] 10.18% [2] 10.18% [2] 10.18% [2]
Total first lien senior secured loans $ 8.2 [3],[4],[5]   $ 6.2 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 8.2 [3],[4],[5]   6.2 [6],[7],[8]                
Investment, Identifier [Axis]: Premier Specialties, Inc. and RMCF V CIV XLIV, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.0   11.0                
Less: funded commitments (2.3)   (2.3)                
Total unfunded commitments 8.7   8.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 8.7   $ 8.7                
Investment, Identifier [Axis]: Premier Specialties, Inc. and RMCF V CIV XLIV, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.84% [1]   10.38% [2] 10.84% [1] 10.84% [1] 10.84% [1] 10.84% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 27.2 [3],[4]   $ 27.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 25.3 [3],[4]   $ 25.6 [6],[7]                
Investment, Identifier [Axis]: Premier Specialties, Inc. and RMCF V CIV XLIV, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.84% [1]   10.38% [2] 10.84% [1] 10.84% [1] 10.84% [1] 10.84% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 2.3 [3],[4]   $ 2.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.1 [3],[4]   2.2 [6],[7]                
Investment, Identifier [Axis]: Premier Specialties, Inc. and RMCF V CIV XLIV, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.0 [4]   2.8 [7]                
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 36.0   36.0                
Less: funded commitments (0.6)   (0.6)                
Total unfunded commitments 35.4   35.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 35.4   35.4                
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.8 [4]   $ 12.8 [7]                
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.91% [1]   7.92% [2] 8.91% [1] 8.91% [1] 8.91% [1] 8.91% [1] 7.92% [2] 7.92% [2] 7.92% [2] 7.92% [2]
Total first lien senior secured loans $ 8.5 [3],[4]   $ 8.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 8.0 [3],[4]   8.1 [6],[7]                
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [16]   $ 0.0 [15]                
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.66% [1]   11.67% [2] 12.66% [1] 12.66% [1] 12.66% [1] 12.66% [1] 11.67% [2] 11.67% [2] 11.67% [2] 11.67% [2]
Total first lien senior secured loans $ 67.1 [4]   $ 67.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 63.7 [4]   64.4 [7]                
Investment, Identifier [Axis]: Prime Buyer, L.L.C.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.9   15.9                
Less: funded commitments (0.7)   (2.7)                
Total unfunded commitments 15.2   13.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 15.2   $ 13.2                
Investment, Identifier [Axis]: Prime Buyer, L.L.C., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.16% [1]   9.88% [2] 10.16% [1] 10.16% [1] 10.16% [1] 10.16% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 0.7 [3],[4]   $ 2.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.6 [3],[4]   2.6 [6],[7]                
Investment, Identifier [Axis]: Primrose Holding Corporation                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0                
Redemptions (cost)     0.0                
Sales (cost)     4.6                
Interest income     0.0                
Capital structuring service fees     0.0                
Dividend income     0.0                
Other income     0.0                
Net realized gains (losses):     28.9                
Net unrealized gains (losses):     (22.4)                
Fair Value     $ 0.0                
Investment, Identifier [Axis]: Priority Holdings, LLC and Priority Technology Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.70% [1]   10.48% [2] 10.70% [1] 10.70% [1] 10.70% [1] 10.70% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.7 [3],[4],[5]   $ 0.7 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.7 [3],[4],[5]   $ 0.7 [6],[7],[8]                
Investment, Identifier [Axis]: Priority Holdings, LLC and Priority Technology Holdings, Inc., Senior preferred stock                      
Schedule of Investments [Line Items]                      
Coupon 17.19% [1]   16.73% [2] 17.19% [1] 17.19% [1] 17.19% [1] 17.19% [1] 16.73% [2] 16.73% [2] 16.73% [2] 16.73% [2]
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 74.5 [3],[4],[5]   $ 73.2 [7],[8]                
Investment, Identifier [Axis]: Priority Holdings, LLC and Priority Technology Holdings, Inc., Warrant to purchase up to 527,226 units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.9 [4],[5]   2.8 [7],[8],[12]                
Investment, Identifier [Axis]: Pritchard Industries, LLC and LJ Pritchard TopCo Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     3.3                
Less: funded commitments     0.0                
Total unfunded commitments     3.3                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     3.3                
Investment, Identifier [Axis]: Pritchard Industries, LLC and LJ Pritchard TopCo Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.5 [4]   $ 8.4 [7]                
Investment, Identifier [Axis]: Pritchard Industries, LLC and LJ Pritchard TopCo Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.52% [1]   10.47% [2] 10.52% [1] 10.52% [1] 10.52% [1] 10.52% [1] 10.47% [2] 10.47% [2] 10.47% [2] 10.47% [2]
Total first lien senior secured loans $ 68.2 [3],[4]   $ 65.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 65.5 [3],[4]   63.1 [6],[7]                
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   2.5                
Redemptions (cost) 0.4   0.3                
Sales (cost) 0.0   0.0                
Interest income 2.4   7.0                
Capital structuring service fees 0.0   0.1                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 10.9   33.6                
Fair Value 109.1   97.3                
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 45.2 [4]   $ 34.3 [7]                
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon 13.36% [1]   12.85% [2] 13.36% [1] 13.36% [1] 13.36% [1] 13.36% [1] 12.85% [2] 12.85% [2] 12.85% [2] 12.85% [2]
Total first lien senior secured loans $ 40.1 [3],[4]   $ 39.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 40.1 [3],[4]   $ 39.1 [6],[7]                
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon 12.36% [1]   11.85% [2] 12.36% [1] 12.36% [1] 12.36% [1] 12.36% [1] 11.85% [2] 11.85% [2] 11.85% [2] 11.85% [2]
Total first lien senior secured loans $ 15.3 [3],[4]   $ 15.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.3 [3],[4]   $ 15.4 [6],[7]                
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon 12.41% [1]   11.88% [2] 12.41% [1] 12.41% [1] 12.41% [1] 12.41% [1] 11.88% [2] 11.88% [2] 11.88% [2] 11.88% [2]
Total first lien senior secured loans $ 7.6 [3],[4]   $ 7.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.6 [3],[4]   $ 7.6 [6],[7]                
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon 12.41% [1]   11.88% [2] 12.41% [1] 12.41% [1] 12.41% [1] 12.41% [1] 11.88% [2] 11.88% [2] 11.88% [2] 11.88% [2]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.9 [3],[4]   0.9 [6],[7]                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     0.1                
Less: funded commitments     0.0                
Total unfunded commitments     0.1                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     0.1                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 17.7 [4]   17.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 17.7 [4]   $ 17.1 [7]                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     14.00%         14.00% 14.00% 14.00% 14.00%
Total first lien senior secured loans 0.2 [4]   $ 0.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [4]   0.1 [7]                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., Series E preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [4]   0.6 [7]                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., Warrant to purchase up to 3,280,444 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.5 [4]   0.8 [7]                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., Warrant to purchase up to 57,322 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [4]   0.2 [7]                
Investment, Identifier [Axis]: ProfitSolv Purchaser, Inc. and PS Co-Invest, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   13.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.1   13.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.1   $ 13.3                
Investment, Identifier [Axis]: ProfitSolv Purchaser, Inc. and PS Co-Invest, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.33% [1]   10.23% [2] 10.33% [1] 10.33% [1] 10.33% [1] 10.33% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 9.9 [3],[4]   $ 5.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.6 [3],[4]   5.4 [6],[7]                
Investment, Identifier [Axis]: ProfitSolv Purchaser, Inc. and PS Co-Invest, L.P., Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.5 [4]   1.5 [7]                
Investment, Identifier [Axis]: Project Alpha Intermediate Holding, Inc. and Qlik Parent, Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 18.1 [4]   14.4 [7]                
Investment, Identifier [Axis]: Project Alpha Intermediate Holding, Inc. and Qlik Parent, Inc., Class B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [4]   $ 0.1 [7]                
Investment, Identifier [Axis]: Project Alpha Intermediate Holding, Inc. and Qlik Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.85% [1]   8.39% [2] 8.85% [1] 8.85% [1] 8.85% [1] 8.85% [1] 8.39% [2] 8.39% [2] 8.39% [2] 8.39% [2]
Total first lien senior secured loans $ 2.8 [4],[11]   $ 2.8 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.8 [4],[11]   2.8 [7],[12]                
Investment, Identifier [Axis]: Project Essential Bidco, Inc. and Project Essential Super Parent, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.1   1.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.1   1.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.1   $ 1.1                
Investment, Identifier [Axis]: Project Essential Bidco, Inc. and Project Essential Super Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.56% [1]   9.99% [2] 10.56% [1] 10.56% [1] 10.56% [1] 10.56% [1] 9.99% [2] 9.99% [2] 9.99% [2] 9.99% [2]
Total first lien senior secured loans $ 36.1 [3],[4]   $ 36.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 35.0 [3],[4]   34.7 [6],[7]                
Investment, Identifier [Axis]: Project Essential Bidco, Inc. and Project Essential Super Parent, Inc., Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 31.4 [4]   30.2 [7]                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.5   5.5                
Less: funded commitments (2.1)   (2.1)                
Total unfunded commitments 3.4   3.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.4   3.4                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.1 [4]   $ 9.3 [7]                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.56% [1]   12.07% [2] 12.56% [1] 12.56% [1] 12.56% [1] 12.56% [1] 12.07% [2] 12.07% [2] 12.07% [2] 12.07% [2]
Total first lien senior secured loans $ 43.5 [3],[4]   $ 43.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 43.5 [3],[4]   $ 43.6 [6],[7]                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.56% [1]   12.07% [2] 12.56% [1] 12.56% [1] 12.56% [1] 12.56% [1] 12.07% [2] 12.07% [2] 12.07% [2] 12.07% [2]
Total first lien senior secured loans $ 12.0 [3],[4]   $ 14.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.0 [3],[4]   $ 14.3 [6],[7]                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.56% [1]   12.07% [2] 12.56% [1] 12.56% [1] 12.56% [1] 12.56% [1] 12.07% [2] 12.07% [2] 12.07% [2] 12.07% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 12.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 12.8 [6],[7]                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     12.07%         12.07% 12.07% 12.07% 12.07%
Total first lien senior secured loans [6],[7]     $ 4.9                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 4.9                
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.56% [1]   12.07% [2] 12.56% [1] 12.56% [1] 12.56% [1] 12.56% [1] 12.07% [2] 12.07% [2] 12.07% [2] 12.07% [2]
Total first lien senior secured loans $ 2.1 [3],[4],[13]   $ 2.1 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.1 [3],[4],[13]   $ 2.1 [6],[7],[14]                
Investment, Identifier [Axis]: Project Ruby Ultimate Parent Corp., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.34% [1]   10.88% [2] 11.34% [1] 11.34% [1] 11.34% [1] 11.34% [1] 10.88% [2] 10.88% [2] 10.88% [2] 10.88% [2]
Total first lien senior secured loans $ 193.1 [3],[4]   $ 193.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 181.5 [3],[4]   181.5 [6],[7]                
Investment, Identifier [Axis]: Proofpoint, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.1   3.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.1   3.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.1   $ 3.1                
Investment, Identifier [Axis]: Proofpoint, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.09% [1]   7.98% [2] 8.09% [1] 8.09% [1] 8.09% [1] 8.09% [1] 7.98% [2] 7.98% [2] 7.98% [2] 7.98% [2]
Total first lien senior secured loans $ 1.0 [3],[4],[11]   $ 1.0 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [3],[4],[11]   $ 0.9 [6],[7],[12]                
Investment, Identifier [Axis]: Proofpoint, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.09% [1]   10.98% [2] 11.09% [1] 11.09% [1] 11.09% [1] 11.09% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 34.6 [3],[4]   $ 34.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 34.6 [3],[4]   34.6 [6],[7]                
Investment, Identifier [Axis]: Pueblo Mechanical and Controls, LLC and OMERS PMC Investment Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.2   3.6                
Less: funded commitments (0.4)   0.0                
Total unfunded commitments 1.8   3.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 1.8   3.6                
Investment, Identifier [Axis]: Pueblo Mechanical and Controls, LLC and OMERS PMC Investment Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.8 [4]   $ 11.0 [7]                
Investment, Identifier [Axis]: Pueblo Mechanical and Controls, LLC and OMERS PMC Investment Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.78% [1]   10.47% [2] 10.78% [1] 10.78% [1] 10.78% [1] 10.78% [1] 10.47% [2] 10.47% [2] 10.47% [2] 10.47% [2]
Total first lien senior secured loans $ 2.8 [3],[4]   $ 1.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.8 [3],[4]   1.4 [6],[7]                
Investment, Identifier [Axis]: Pueblo Mechanical and Controls, LLC and OMERS PMC Investment Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 13.00%     13.00% 13.00% 13.00% 13.00%        
Total first lien senior secured loans [3],[4] $ 0.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.4                    
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     9.8                
Less: funded commitments     (9.8)                
Total unfunded commitments     0.0                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 0.0                
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.85% [1]   11.63% [2] 12.85% [1] 12.85% [1] 12.85% [1] 12.85% [1] 11.63% [2] 11.63% [2] 11.63% [2] 11.63% [2]
Total first lien senior secured loans $ 7.7 [3],[4]   $ 16.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 7.5 [3],[4]   $ 16.9 [6],[7]                
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     11.63%         11.63% 11.63% 11.63% 11.63%
Total first lien senior secured loans [6],[7]     $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 0.1                
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     11.60%         11.60% 11.60% 11.60% 11.60%
Total first lien senior secured loans [6],[7],[14]     $ 9.7                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7],[14]     9.7                
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, Preferred membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.0   0.9                
Investment, Identifier [Axis]: Pyramid-BMC IntermediateCo I, LLC and Pyramid Investors, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.6                    
Less: funded commitments 0.0                    
Total unfunded commitments 1.6                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 1.6                    
Investment, Identifier [Axis]: QF Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.1   2.3                
Less: funded commitments (0.2)   0.0                
Total unfunded commitments 0.9   2.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.9   $ 2.3                
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.16% [1]   11.02% [2] 11.16% [1] 11.16% [1] 11.16% [1] 11.16% [1] 11.02% [2] 11.02% [2] 11.02% [2] 11.02% [2]
Total first lien senior secured loans $ 8.1 [3],[4]   $ 8.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.1 [3],[4]   $ 8.1 [6],[7]                
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.12% [1]   10.43% [2] 11.12% [1] 11.12% [1] 11.12% [1] 11.12% [1] 10.43% [2] 10.43% [2] 10.43% [2] 10.43% [2]
Total first lien senior secured loans $ 4.9 [3],[4]   $ 6.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.9 [3],[4]   $ 6.8 [6],[7]                
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.16% [1]   10.64% [2] 11.16% [1] 11.16% [1] 11.16% [1] 11.16% [1] 10.64% [2] 10.64% [2] 10.64% [2] 10.64% [2]
Total first lien senior secured loans $ 6.8 [3],[4]   $ 3.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.8 [3],[4]   3.7 [6],[7]                
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.06%     11.06% 11.06% 11.06% 11.06%        
Total first lien senior secured loans [3],[4] $ 0.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.2                    
Investment, Identifier [Axis]: Qnnect, LLC and Connector TopCo, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.7   2.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.7   2.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.7   $ 2.8                
Investment, Identifier [Axis]: Qnnect, LLC and Connector TopCo, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.69% [1]   11.11% [2] 11.69% [1] 11.69% [1] 11.69% [1] 11.69% [1] 11.11% [2] 11.11% [2] 11.11% [2] 11.11% [2]
Total first lien senior secured loans $ 10.7 [3],[4]   $ 10.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.4 [3],[4]   10.3 [6],[7]                
Investment, Identifier [Axis]: Qnnect, LLC and Connector TopCo, LP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.9 [4]   9.9 [7]                
Investment, Identifier [Axis]: R2 Acquisition Corp., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [4]   0.1 [7]                
Investment, Identifier [Axis]: RB Holdings InterCo, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.6   5.6                
Less: funded commitments (1.8)   (1.8)                
Total unfunded commitments 3.8   3.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.8   $ 3.8                
Investment, Identifier [Axis]: RB Holdings InterCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.85% [1]   9.32% [2] 9.85% [1] 9.85% [1] 9.85% [1] 9.85% [1] 9.32% [2] 9.32% [2] 9.32% [2] 9.32% [2]
Total first lien senior secured loans $ 11.5 [3],[4]   $ 11.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.3 [3],[4]   $ 11.2 [6],[7]                
Investment, Identifier [Axis]: RB Holdings InterCo, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [1]   9.28% [2] 9.92% [1] 9.92% [1] 9.92% [1] 9.92% [1] 9.28% [2] 9.28% [2] 9.28% [2] 9.28% [2]
Total first lien senior secured loans $ 1.8 [3],[4]   $ 1.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [3],[4]   1.7 [6],[7]                
Investment, Identifier [Axis]: RC V Tecmo Investor LLC, Common member units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 22.8 [4]   22.9 [7]                
Investment, Identifier [Axis]: RD Holdco Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0                
Redemptions (cost)     0.1                
Sales (cost)     0.0                
Interest income     0.0                
Capital structuring service fees     0.0                
Dividend income     0.0                
Other income     0.0                
Net realized gains (losses):     0.0                
Net unrealized gains (losses):     (10.6)                
Fair Value     10.3                
Investment, Identifier [Axis]: RD Holdco Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: RD Holdco Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 25.1   24.2 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 11.6   10.2 [7],[10]                
Investment, Identifier [Axis]: RD Holdco Inc., Warrants to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: RE Community Holdings GP, LLC and RE Community Holdings, LP, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: RE Community Holdings GP, LLC and RE Community Holdings, LP, Limited partnership interest 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0                
Investment, Identifier [Axis]: RF HP SCF Investor, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 26.9 [4],[5]   25.9 [7],[8]                
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.9   2.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.9   2.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 2.9   2.9                
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.5 [4]   $ 5.5 [7]                
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.48% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: RSC Acquisition, Inc. and RSC Insurance Brokerage, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   0.6                
Less: funded commitments (0.3)   0.0                
Total unfunded commitments 0.3   0.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.3   $ 0.6                
Investment, Identifier [Axis]: RSC Acquisition, Inc. and RSC Insurance Brokerage, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.35% [1]   9.79% [2] 10.35% [1] 10.35% [1] 10.35% [1] 10.35% [1] 9.79% [2] 9.79% [2] 9.79% [2] 9.79% [2]
Total first lien senior secured loans $ 32.7 [3],[4]   $ 32.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 31.7 [3],[4]   31.8 [6],[7]                
Investment, Identifier [Axis]: RSC Acquisition, Inc. and RSC Insurance Brokerage, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.68%     10.68% 10.68% 10.68% 10.68%        
Total first lien senior secured loans [3],[4] $ 0.3                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.3                    
Investment, Identifier [Axis]: RTI Surgical, Inc. and Pioneer Surgical Technology, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.9   15.9                
Less: funded commitments (6.1)   (9.8)                
Total unfunded commitments 9.8   6.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.8   $ 6.1                
Investment, Identifier [Axis]: RTI Surgical, Inc. and Pioneer Surgical Technology, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.86% [1]   10.02% [2] 11.86% [1] 11.86% [1] 11.86% [1] 11.86% [1] 10.02% [2] 10.02% [2] 10.02% [2] 10.02% [2]
Total first lien senior secured loans $ 22.4 [3],[4]   $ 22.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 22.4 [3],[4]   $ 22.3 [6],[7]                
Investment, Identifier [Axis]: RTI Surgical, Inc. and Pioneer Surgical Technology, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.53% [1]   11.09% [2] 11.53% [1] 11.53% [1] 11.53% [1] 11.53% [1] 11.09% [2] 11.09% [2] 11.09% [2] 11.09% [2]
Total first lien senior secured loans $ 6.1 [3],[4]   $ 9.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.1 [3],[4]   9.7 [6],[7]                
Investment, Identifier [Axis]: Radius Aerospace, Inc. and Radius Aerospace Europe Limited                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.8   2.8                
Less: funded commitments (0.6)   (0.7)                
Total unfunded commitments 2.2   2.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.2   $ 2.1                
Investment, Identifier [Axis]: Radius Aerospace, Inc. and Radius Aerospace Europe Limited, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.93% [1]   8.68% [2] 9.93% [1] 9.93% [1] 9.93% [1] 9.93% [1] 8.68% [2] 8.68% [2] 8.68% [2] 8.68% [2]
Total first lien senior secured loans $ 0.3 [3],[4],[5]   $ 0.4 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4],[5]   $ 0.4 [6],[7],[8]                
Investment, Identifier [Axis]: Radius Aerospace, Inc. and Radius Aerospace Europe Limited, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.70% [1]   10.08% [2] 10.70% [1] 10.70% [1] 10.70% [1] 10.70% [1] 10.08% [2] 10.08% [2] 10.08% [2] 10.08% [2]
Total first lien senior secured loans $ 0.3 [3],[4],[5]   $ 0.4 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.3 [3],[4],[5]   0.4 [6],[7],[8]                
Investment, Identifier [Axis]: Radwell Parent, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.4   4.4                
Less: funded commitments (0.6)   0.0                
Total unfunded commitments 3.8   4.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.8   $ 4.4                
Investment, Identifier [Axis]: Radwell Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.65% [1]   11.33% [2] 11.65% [1] 11.65% [1] 11.65% [1] 11.65% [1] 11.33% [2] 11.33% [2] 11.33% [2] 11.33% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 19.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   18.9 [6],[7]                
Investment, Identifier [Axis]: Radwell Parent, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.56%     11.56% 11.56% 11.56% 11.56%        
Total first lien senior secured loans [3],[4] $ 0.6                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.6                    
Investment, Identifier [Axis]: Raptor Technologies, LLC, Sycamore Bidco LTD and Rocket Parent, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.4   4.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.4   4.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 4.4   4.4                
Investment, Identifier [Axis]: Raptor Technologies, LLC, Sycamore Bidco LTD and Rocket Parent, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.7   $ 5.9                
Investment, Identifier [Axis]: Raptor Technologies, LLC, Sycamore Bidco LTD and Rocket Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.23% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 8.5 [3],[4],[5]   $ 8.5 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.4 [3],[4],[5]   $ 8.2 [6],[7],[8]                
Investment, Identifier [Axis]: Rawlings Sporting Goods Company, Inc. and Easton Diamond Sports, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.48% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 49.6 [3],[4]   $ 49.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 49.6 [3],[4]   $ 49.7 [6],[7]                
Investment, Identifier [Axis]: Rawlings Sporting Goods Company, Inc. and Easton Diamond Sports, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.48% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: RealPage, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.34% [1]   10.88% [2] 11.34% [1] 11.34% [1] 11.34% [1] 11.34% [1] 10.88% [2] 10.88% [2] 10.88% [2] 10.88% [2]
Total first lien senior secured loans $ 84.1 [3],[4]   $ 84.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 79.9 [3],[4]   82.4 [6],[7]                
Investment, Identifier [Axis]: Reddy Ice LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2   0.2                
Less: funded commitments (0.1)   0.0                
Total unfunded commitments 0.1   0.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.1   $ 0.2                
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.79% [1]   10.24% [2] 10.79% [1] 10.79% [1] 10.79% [1] 10.79% [1] 10.24% [2] 10.24% [2] 10.24% [2] 10.24% [2]
Total first lien senior secured loans $ 61.1 [3],[4]   $ 61.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 59.9 [3],[4]   $ 60.0 [6],[7]                
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.79% [1]   10.24% [2] 10.79% [1] 10.79% [1] 10.79% [1] 10.79% [1] 10.24% [2] 10.24% [2] 10.24% [2] 10.24% [2]
Total first lien senior secured loans $ 4.2 [3],[4]   $ 4.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.1 [3],[4]   $ 4.2 [6],[7]                
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.79% [1]   10.24% [2] 10.79% [1] 10.79% [1] 10.79% [1] 10.79% [1] 10.24% [2] 10.24% [2] 10.24% [2] 10.24% [2]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.9 [3],[4]   0.9 [6],[7]                
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.16%     11.16% 11.16% 11.16% 11.16%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.1                    
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.8   4.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.8   4.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.8   $ 4.5                
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.17% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.17% [2] 11.17% [2] 11.17% [2] 11.17% [2]
Total first lien senior secured loans $ 1.4 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.4 [3],[4]   $ 0.8 [6],[7]                
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.17% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.17% [2] 11.17% [2] 11.17% [2] 11.17% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.17% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.17% [2] 11.17% [2] 11.17% [2] 11.17% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC, Series D units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 42.2   33.9                
Investment, Identifier [Axis]: Reef Lifestyle, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 53.0   37.7                
Less: funded commitments (53.0)   (37.7)                
Total unfunded commitments 0.0   0.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon 14.89% [1]   12.74% [2] 14.89% [1] 14.89% [1] 14.89% [1] 14.89% [1] 12.74% [2] 12.74% [2] 12.74% [2] 12.74% [2]
Total first lien senior secured loans $ 23.3 [3],[4]   $ 23.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 22.2 [3],[4]   $ 22.9 [6],[7]                
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.15%         10.15% 10.15% 10.15% 10.15%
Total first lien senior secured loans 1.6 [3],[4]   $ 1.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.5 [3],[4]   $ 1.3 [6],[7]                
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured revolving loan 1                      
Schedule of Investments [Line Items]                      
Coupon 14.82% [1]   14.50% [2] 14.82% [1] 14.82% [1] 14.82% [1] 14.82% [1] 14.50% [2] 14.50% [2] 14.50% [2] 14.50% [2]
Total first lien senior secured loans $ 50.2 [3],[4],[13]   $ 35.5 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 47.7 [3],[4],[13]   $ 34.4 [6],[7],[14]                
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     14.32%         14.32% 14.32% 14.32% 14.32%
Total first lien senior secured loans 1.4 [3],[4]   $ 1.0 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.4 [3],[4]   1.0 [6],[7],[14]                
Investment, Identifier [Axis]: Regent Education, Inc., Warrant to purchase up to 5,393,194 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Regent Education, Inc., Warrant to purchase up to 987 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Registrar Intermediate, LLC and PSP Registrar Co-Investment Fund, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.0   28.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 28.0   28.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 28.0   $ 28.0                
Investment, Identifier [Axis]: Registrar Intermediate, LLC and PSP Registrar Co-Investment Fund, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.84% [1]   9.38% [2] 9.84% [1] 9.84% [1] 9.84% [1] 9.84% [1] 9.38% [2] 9.38% [2] 9.38% [2] 9.38% [2]
Total first lien senior secured loans $ 2.7 [3],[4]   $ 2.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.7 [3],[4]   2.7 [6],[7]                
Investment, Identifier [Axis]: Registrar Intermediate, LLC and PSP Registrar Co-Investment Fund, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.2 [4]   2.6 [7]                
Investment, Identifier [Axis]: Relativity ODA LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.8   3.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.8   3.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.8   3.8                
Investment, Identifier [Axis]: Relativity ODA LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 22.8 [3],[4]   22.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 22.8 [3],[4]   22.5 [6],[7]                
Investment, Identifier [Axis]: Repairify, Inc. and Repairify Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.3   7.3                
Less: funded commitments (1.2)   0.0                
Total unfunded commitments 6.1   7.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.1   7.3                
Investment, Identifier [Axis]: Repairify, Inc. and Repairify Holdings, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.4 [4]   4.4 [7]                
Investment, Identifier [Axis]: Repairify, Inc. and Repairify Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.03%     10.03% 10.03% 10.03% 10.03%        
Total first lien senior secured loans [3],[4] $ 1.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 1.2                    
Investment, Identifier [Axis]: Revalize, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.9   0.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.9   $ 0.9                
Investment, Identifier [Axis]: Revalize, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.66% [1]   10.48% [2] 10.66% [1] 10.66% [1] 10.66% [1] 10.66% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.7 [3],[4]   $ 0.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [3],[4]   $ 0.6 [6],[7]                
Investment, Identifier [Axis]: Revalize, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.46%         10.46% 10.46% 10.46% 10.46%
Total first lien senior secured loans [7]     $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     0.0                
Investment, Identifier [Axis]: Rialto Management Group, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.3   1.3                
Less: funded commitments (0.3)   (0.2)                
Total unfunded commitments 1.0   1.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.0   $ 1.1                
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% 9.88% 9.88% 9.88%
Total first lien senior secured loans $ 0.3 [3],[4],[5]   $ 0.3 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4],[5]   $ 0.3 [7],[8]                
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 0.1 [7],[8]                
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4],[5]   0.1 [7],[8]                
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [8],[15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [16]   0.0 [8],[15]                
Investment, Identifier [Axis]: Riser Merger Sub, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.4   2.8                
Less: funded commitments (0.4)   0.0                
Total unfunded commitments 1.0   2.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.0   $ 2.8                
Investment, Identifier [Axis]: Riser Merger Sub, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.33%         9.33% 9.33% 9.33% 9.33%
Total first lien senior secured loans [6],[7]     $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     0.7                
Investment, Identifier [Axis]: Riser Merger Sub, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.65%     10.65% 10.65% 10.65% 10.65%        
Total first lien senior secured loans [3],[4] $ 1.5                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 1.5                    
Investment, Identifier [Axis]: Riser Merger Sub, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 9.93%     9.93% 9.93% 9.93% 9.93%        
Total first lien senior secured loans [3],[4] $ 0.7                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.6                    
Investment, Identifier [Axis]: Riser Merger Sub, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.75%     12.75% 12.75% 12.75% 12.75%        
Total first lien senior secured loans [3],[4] $ 0.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.4                    
Investment, Identifier [Axis]: Riverview Power LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     8.9                
Less: funded commitments     0.0                
Total unfunded commitments     8.9                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 8.9                
Investment, Identifier [Axis]: Riverview Power LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.16% [1]   13.73% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.73% [2] 13.73% [2] 13.73% [2] 13.73% [2]
Total first lien senior secured loans $ 42.4 [3],[4]   $ 57.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 42.4 [3],[4]   57.6 [6],[7]                
Investment, Identifier [Axis]: Rodeo AcquisitionCo LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.2   6.2                
Less: funded commitments (1.7)   (1.3)                
Total unfunded commitments 4.5   4.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.5   $ 4.9                
Investment, Identifier [Axis]: Rodeo AcquisitionCo LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.95% [1]   10.38% [2] 10.95% [1] 10.95% [1] 10.95% [1] 10.95% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 16.9 [3],[4]   $ 16.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 16.0 [3],[4]   $ 16.1 [6],[7]                
Investment, Identifier [Axis]: Rodeo AcquisitionCo LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.94% [1]   10.38% [2] 10.94% [1] 10.94% [1] 10.94% [1] 10.94% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 1.7 [3],[4]   $ 1.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.6 [3],[4]   1.2 [6],[7]                
Investment, Identifier [Axis]: Rug Doctor, LLC and RD Holdco Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0                    
Redemptions (cost) 0.0                    
Sales (cost) 0.0                    
Interest income 0.0                    
Capital structuring service fees 0.0                    
Dividend income 0.0                    
Other income 0.0                    
Net realized gains (losses): 0.0                    
Net unrealized gains (losses): 0.9                    
Fair Value 11.6                    
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC)                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   (0.1)                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC), Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC), Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC), Warrant to purchase up to 3,157,895 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: SCI PH Parent, Inc., Series B shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [4]   4.2 [7]                
Investment, Identifier [Axis]: SCIH Salt Holdings Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5                
Less: funded commitments 0.0   (2.6)                
Total unfunded commitments 7.5   4.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.5   $ 4.9                
Investment, Identifier [Axis]: SCIH Salt Holdings Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.15%         8.15% 8.15% 8.15% 8.15%
Total first lien senior secured loans [6],[7],[14]     $ 2.3                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7],[14]     2.2                
Investment, Identifier [Axis]: SCM Insurance Services Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0   4.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.0   4.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 4.0   $ 4.0                
Investment, Identifier [Axis]: SCM Insurance Services Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.27% [1]   11.16% [2] 11.27% [1] 11.27% [1] 11.27% [1] 11.27% [1] 11.16% [2] 11.16% [2] 11.16% [2] 11.16% [2]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 61.1 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4],[5]   $ 61.1 [6],[7],[8]                
Investment, Identifier [Axis]: SE1 Generation, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon 12.25% [1]   12.25% [2] 12.25% [1] 12.25% [1] 12.25% [1] 12.25% [1] 12.25% [2] 12.25% [2] 12.25% [2] 12.25% [2]
Total first lien senior secured loans $ 55.9 [4]   $ 57.5 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 55.9 [4]   57.5 [7]                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.2   15.2                
Less: funded commitments (8.3)   (8.3)                
Total unfunded commitments 6.9   6.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 6.9   $ 6.9                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.30% [1]   9.48% [2] 10.30% [1] 10.30% [1] 10.30% [1] 10.30% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 10.0 [3],[4]   $ 10.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.7 [3],[4]   $ 9.8 [6],[7]                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.30% [1]   9.48% [2] 10.30% [1] 10.30% [1] 10.30% [1] 10.30% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 6.2 [3],[4]   $ 6.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.0 [3],[4]   $ 6.1 [6],[7]                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.30% [1]   9.48% [2] 10.30% [1] 10.30% [1] 10.30% [1] 10.30% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.4 [3],[4]   $ 0.4 [6],[7]                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.30% [1]   9.48% [2] 10.30% [1] 10.30% [1] 10.30% [1] 10.30% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 8.3 [3]   $ 8.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.0 [3]   $ 8.1 [6],[7]                
Investment, Identifier [Axis]: SG Acquisition, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.84% [1]   9.17% [2] 9.84% [1] 9.84% [1] 9.84% [1] 9.84% [1] 9.17% [2] 9.17% [2] 9.17% [2] 9.17% [2]
Total first lien senior secured loans $ 33.8 [3],[4]   $ 33.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 33.5 [3],[4]   33.5 [6],[7]                
Investment, Identifier [Axis]: SHO Holding I Corporation, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 128.6 [4],[9]   124.9 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 70.7 [4],[9]   82.4 [7],[10]                
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     3.8                
Less: funded commitments     0.0                
Total unfunded commitments     3.8                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     3.8                
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc., Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.3 [4]   0.1 [7]                
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc., Series B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   9.3 [7]                
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc., Series D units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 0.7                    
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.8                    
Less: funded commitments 0.0                    
Total unfunded commitments 3.8                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 3.8                    
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.0 [4]   4.8 [7]                
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 84.7 [3],[4]   61.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 80.4 [3],[4]   $ 56.2 [6],[7]                
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     12.19%         12.19% 12.19% 12.19% 12.19%
Total first lien senior secured loans [6],[7]     $ 22.7                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     20.9                
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, Warrant to purchase units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] 4.2                    
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, Warrant to purchase up to 6,118 Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     4.7                
Investment, Identifier [Axis]: SSE Buyer, Inc., Supply Source Enterprises, Inc., Impact Products LLC, The Safety Zone, LLC and SSE Parent, LP, Limited partnership class A-1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0 [7]                
Investment, Identifier [Axis]: SSE Buyer, Inc., Supply Source Enterprises, Inc., Impact Products LLC, The Safety Zone, LLC and SSE Parent, LP, Limited partnership class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [4]   0.0 [7]                
Investment, Identifier [Axis]: SSE Buyer, Inc., Supply Source Enterprises, Inc., Impact Products LLC, The Safety Zone, LLC and SSE Parent, LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 22.5 [3],[4]   21.0 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 11.2 [3],[4]   14.3 [7],[10]                
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.5   3.3                
Less: funded commitments (0.4)   0.0                
Total unfunded commitments 12.1   3.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 12.1   3.3                
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 7.5   $ 4.8                
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.33% [1]   9.93% [2] 11.33% [1] 11.33% [1] 11.33% [1] 11.33% [1] 9.93% [2] 9.93% [2] 9.93% [2] 9.93% [2]
Total first lien senior secured loans $ 2.1 [3],[4]   $ 1.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.1 [3],[4]   1.3 [6],[7]                
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.78%     11.78% 11.78% 11.78% 11.78%        
Total first lien senior secured loans [3],[4] $ 1.6                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 1.6                    
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.36%     10.36% 10.36% 10.36% 10.36%        
Total first lien senior secured loans [3],[4] $ 1.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 1.1                    
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.38%     11.38% 11.38% 11.38% 11.38%        
Total first lien senior secured loans [3],[4] $ 0.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.4                    
Investment, Identifier [Axis]: SVP-Singer Holdings Inc. and SVP-Singer Holdings LP, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4]   $ 4.0 [7]                
Investment, Identifier [Axis]: SVP-Singer Holdings Inc. and SVP-Singer Holdings LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.91% [1]   11.48% [2] 11.91% [1] 11.91% [1] 11.91% [1] 11.91% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 44.3 [3],[4]   $ 44.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 34.2 [3],[4]   $ 36.4 [6],[7]                
Investment, Identifier [Axis]: Safe Home Security, Inc., Security Systems Inc., Safe Home Monitoring, Inc., National Protective Services, Inc., Bright Integrations LLC and Medguard Alert, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.09% [1]   11.63% [2] 12.09% [1] 12.09% [1] 12.09% [1] 12.09% [1] 11.63% [2] 11.63% [2] 11.63% [2] 11.63% [2]
Total first lien senior secured loans $ 47.7 [3],[4]   $ 47.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 47.7 [3],[4]   47.9 [6],[7]                
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.1   10.5                
Less: funded commitments 0.0   (5.9)                
Total unfunded commitments 3.1   4.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.1   $ 4.6                
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.67% [1]   10.14% [2] 10.67% [1] 10.67% [1] 10.67% [1] 10.67% [1] 10.14% [2] 10.14% [2] 10.14% [2] 10.14% [2]
Total first lien senior secured loans $ 0.7 [3],[4]   $ 5.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [3],[4]   $ 5.9 [6],[7]                
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.13%         10.13% 10.13% 10.13% 10.13%
Total first lien senior secured loans [6],[7]     $ 14.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     13.9                
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC, Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 18.3   16.0                
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC, Tender Lawn Care ULC and Landscape Parallel Partners, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.3   4.6                
Less: funded commitments (0.5)   (0.2)                
Total unfunded commitments 2.8   4.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 2.8   4.4                
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC, Tender Lawn Care ULC and Landscape Parallel Partners, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 17.9 [4]   $ 14.7 [7]                
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC, Tender Lawn Care ULC and Landscape Parallel Partners, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.14% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.14% [2] 10.14% [2] 10.14% [2] 10.14% [2]
Total first lien senior secured loans $ 1.9 [3],[4]   $ 0.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.9 [3],[4]   $ 0.6 [6],[7]                
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC, Tender Lawn Care ULC and Landscape Parallel Partners, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.14% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.14% [2] 10.14% [2] 10.14% [2] 10.14% [2]
Total first lien senior secured loans $ 0.5 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.5 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: SelectQuote, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 12.91% [1]   12.42% [2] 12.91% [1] 12.91% [1] 12.91% [1] 12.91% [1] 12.42% [2] 12.42% [2] 12.42% [2] 12.42% [2]
Total first lien senior secured loans $ 22.2 [3],[4]   $ 22.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.5 [3],[4]   19.5 [6],[7]                
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 49.0   317.8                
Redemptions (cost) 41.4   31.1                
Sales (cost) 0.0   0.0                
Interest income 42.4   146.3                
Capital structuring service fees 0.2   16.9                
Dividend income 0.0   0.0                
Other income 1.1   5.5                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (25.8)   (25.3)                
Fair Value 1,230.4   1,248.6                
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [5]   $ 0.0 [8]                
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC, Subordinated certificates                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.19% [1]   12.77% [2] 13.19% [1] 13.19% [1] 13.19% [1] 13.19% [1] 12.77% [2] 12.77% [2] 12.77% [2] 12.77% [2]
Total first lien senior secured loans $ 1,281.7 [5],[16]   $ 1,274.1 [8],[21]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1,230.4 [5],[16]   $ 1,248.6 [8],[21]                
Investment, Identifier [Axis]: Service Logic Acquisition, Inc. and MSHC, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.59%   10.18% [1] 9.59% 9.59% 9.59% 9.59% 10.18% [1] 10.18% [1] 10.18% [1] 10.18% [1]
Total first lien senior secured loans $ 0.1   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1   0.1 [6],[7]                
Investment, Identifier [Axis]: Shermco Intermediate Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0   4.0                
Less: funded commitments (1.6)   (2.7)                
Total unfunded commitments 2.4   1.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.4   $ 1.3                
Investment, Identifier [Axis]: Shermco Intermediate Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.31% [1]   10.82% [2] 11.31% [1] 11.31% [1] 11.31% [1] 11.31% [1] 10.82% [2] 10.82% [2] 10.82% [2] 10.82% [2]
Total first lien senior secured loans $ 1.6 [4]   $ 2.7 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.6 [4]   2.7 [7]                
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 1.6   3.2                
Redemptions (cost) 0.0   4.5                
Sales (cost) 0.0   18.9                
Interest income 0.0   0.8                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.1                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (1.9)   3.0                
Fair Value 5.7   6.0                
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.5   2.5                
Less: funded commitments (1.7)   0.0                
Total unfunded commitments 0.8   2.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.8   2.5                
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.8 [4]   1.8 [7]                
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, Class C preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.8 [4]   $ 1.8 [7]                
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   9.84% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 9.84% [2] 9.84% [2] 9.84% [2] 9.84% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.00%     12.00% 12.00% 12.00% 12.00%        
Total first lien senior secured loans [3],[4] $ 1.7                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 1.7                    
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4]   2.3 [7]                
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0                
Less: funded commitments 0.0   (1.8)                
Total unfunded commitments 5.0   3.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 5.0   3.2                
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.8 [4]   $ 13.9 [7]                
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.45% [1]   10.90% [2] 11.45% [1] 11.45% [1] 11.45% [1] 11.45% [1] 10.90% [2] 10.90% [2] 10.90% [2] 10.90% [2]
Total first lien senior secured loans $ 6.2 [3],[4]   $ 26.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.2 [3],[4]   $ 26.8 [6],[7]                
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.90% [1]   10.90% [2] 10.90% [1] 10.90% [1] 10.90% [1] 10.90% [1] 10.90% [2] 10.90% [2] 10.90% [2] 10.90% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.90% [1]   10.59% [2] 10.90% [1] 10.90% [1] 10.90% [1] 10.90% [1] 10.59% [2] 10.59% [2] 10.59% [2] 10.59% [2]
Total first lien senior secured loans $ 26.7 [3]   $ 1.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 26.7 [3]   1.8 [6],[7]                
Investment, Identifier [Axis]: SilverBow Resources, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 23.2 [4],[5],[11]   28.7 [7]                
Investment, Identifier [Axis]: SiroMed Physician Services, Inc. and SiroMed Equity Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.1   7.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 7.1   7.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.1   7.1                
Investment, Identifier [Axis]: SiroMed Physician Services, Inc. and SiroMed Equity Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [4]   $ 1.2 [7]                
Investment, Identifier [Axis]: SiroMed Physician Services, Inc. and SiroMed Equity Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.91% [1]   9.48% [2] 9.91% [1] 9.91% [1] 9.91% [1] 9.91% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 9.2 [3],[4]   $ 10.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.2 [3],[4]   10.3 [6],[7]                
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.0   2.0                
Less: funded commitments (0.1)   0.0                
Total unfunded commitments 1.9   2.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 1.9   2.0                
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.8 [4]   $ 8.6 [7]                
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.29% [1]   11.29% [2] 11.29% [1] 11.29% [1] 11.29% [1] 11.29% [1] 11.29% [2] 11.29% [2] 11.29% [2] 11.29% [2]
Total first lien senior secured loans $ 11.9 [3],[4]   $ 11.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.9 [3],[4]   11.9 [6],[7]                
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.40%     11.40% 11.40% 11.40% 11.40%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.1                    
Investment, Identifier [Axis]: SocialFlow, Inc., Warrant to purchase shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Sophia, L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.16% [1]   12.73% [2] 13.16% [1] 13.16% [1] 13.16% [1] 13.16% [1] 12.73% [2] 12.73% [2] 12.73% [2] 12.73% [2]
Total first lien senior secured loans $ 105.9 [3],[4]   $ 105.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 102.7 [3],[4]   103.8 [6],[7]                
Investment, Identifier [Axis]: SoundCloud Limited, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [4],[5]   0.7 [7],[8]                
Investment, Identifier [Axis]: Spirit RR Holdings, Inc. and Winterfell Co-Invest SCSp                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.7   1.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.7   1.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.7   $ 1.7                
Investment, Identifier [Axis]: Spirit RR Holdings, Inc. and Winterfell Co-Invest SCSp, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.50% [1]   11.18% [2] 11.50% [1] 11.50% [1] 11.50% [1] 11.50% [1] 11.18% [2] 11.18% [2] 11.18% [2] 11.18% [2]
Total first lien senior secured loans $ 2.6 [3],[4]   $ 2.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.5 [3],[4]   2.5 [6],[7]                
Investment, Identifier [Axis]: Spirit RR Holdings, Inc. and Winterfell Co-Invest SCSp, Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.7 [4]   $ 10.5 [7]                
Investment, Identifier [Axis]: Spring Insurance Solutions, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.66% [1]   11.23% [2] 11.66% [1] 11.66% [1] 11.66% [1] 11.66% [1] 11.23% [2] 11.23% [2] 11.23% [2] 11.23% [2]
Total first lien senior secured loans $ 22.0 [3],[4]   $ 22.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 19.3 [3],[4]   $ 19.6 [6],[7]                
Investment, Identifier [Axis]: Stamps.com Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.13%         10.13% 10.13% 10.13% 10.13%
Total first lien senior secured loans [6],[7]     $ 146.8                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     140.9                
Investment, Identifier [Axis]: Star US Bidco LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.5   8.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.5   8.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.5   8.5                
Investment, Identifier [Axis]: Startec Equity, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.0   0.0                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.0   0.0                
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: Startec Equity, LLC, Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Stealth Holding LLC and UCIT Online Security Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.53% [1]   10.54% [2] 11.53% [1] 11.53% [1] 11.53% [1] 11.53% [1] 10.54% [2] 10.54% [2] 10.54% [2] 10.54% [2]
Total first lien senior secured loans $ 52.8 [3],[4],[5]   $ 51.3 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 52.3 [3],[4],[5]   $ 50.3 [6],[7],[8]                
Investment, Identifier [Axis]: Stealth Holding LLC and UCIT Online Security Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   11.08% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 11.08% [2] 11.08% [2] 11.08% [2] 11.08% [2]
Total first lien senior secured loans $ 5.2 [3],[4],[5]   $ 5.2 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.1 [3],[4],[5]   $ 5.1 [6],[7],[8]                
Investment, Identifier [Axis]: Stealth Holding LLC and UCIT Online Security Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.75% [1]   13.75% [2] 13.75% [1] 13.75% [1] 13.75% [1] 13.75% [1] 13.75% [2] 13.75% [2] 13.75% [2] 13.75% [2]
Total first lien senior secured loans $ 0.8 [3],[4],[5]   $ 2.5 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.8 [3],[4],[5]   2.4 [6],[7],[8]                
Investment, Identifier [Axis]: Storable, Inc. and EQT IX Co-Investment (E) SCSP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.1 [4],[5]   $ 7.0 [7],[8]                
Investment, Identifier [Axis]: Storable, Inc. and EQT IX Co-Investment (E) SCSP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.54% [1]   11.54% [2] 11.54% [1] 11.54% [1] 11.54% [1] 11.54% [1] 11.54% [2] 11.54% [2] 11.54% [2] 11.54% [2]
Total first lien senior secured loans $ 42.8 [3],[4]   $ 42.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 41.5 [3],[4]   $ 41.1 [6],[7]                
Investment, Identifier [Axis]: Storable, Inc. and EQT IX Co-Investment (E) SCSP, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.54% [1]   11.54% [2] 11.54% [1] 11.54% [1] 11.54% [1] 11.54% [1] 11.54% [2] 11.54% [2] 11.54% [2] 11.54% [2]
Total first lien senior secured loans $ 10.3 [3],[4]   $ 10.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.0 [3],[4]   9.9 [6],[7]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class A redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class B redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class C redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class D redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class E redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class F redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class G redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class H redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4],[5]   2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class I redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.4 [4],[5]   $ 2.2 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 3.75% [1]   375.00% [2] 3.75% [1] 3.75% [1] 3.75% [1] 3.75% [1] 375.00% [2] 375.00% [2] 375.00% [2] 375.00% [2]
Total first lien senior secured loans $ 67.0 [4],[5]   $ 66.0 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 67.0 [4],[5]   66.0 [7],[8]                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.2 [4],[5]   0.2 [7],[8]                
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 21.3   21.6                
Less: funded commitments (1.6)   (0.4)                
Total unfunded commitments 19.7   21.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 19.7   21.2                
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.9 [4]   $ 9.3 [7]                
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 52.2 [3],[4]   $ 52.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 50.6 [3],[4]   $ 50.4 [6],[7]                
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 5.3 [3],[4]   $ 5.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.2 [3],[4]   5.2 [6],[7]                
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 12.75%     12.75% 12.75% 12.75% 12.75%        
Total first lien senior secured loans $ 1.2 [3],[4],[13]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.2 [3],[4],[13]   0.0 [15]                
Investment, Identifier [Axis]: Sundance Energy Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0                
Redemptions (cost)     41.0                
Sales (cost)     0.0                
Interest income     0.0                
Capital structuring service fees     0.0                
Dividend income     0.0                
Other income     0.0                
Net realized gains (losses):     (22.6)                
Net unrealized gains (losses):     1.2                
Fair Value     0.0                
Investment, Identifier [Axis]: Sundance Group Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.0   3.0                
Less: funded commitments (0.3)   0.0                
Total unfunded commitments 2.7   3.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.7   $ 3.0                
Investment, Identifier [Axis]: Sundance Group Holdings, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.99% [1]   10.75% [2] 10.99% [1] 10.99% [1] 10.99% [1] 10.99% [1] 10.75% [2] 10.75% [2] 10.75% [2] 10.75% [2]
Total first lien senior secured loans $ 20.1 [3],[4]   $ 20.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 19.9 [3],[4]   $ 19.9 [6],[7]                
Investment, Identifier [Axis]: Sundance Group Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.16% [1]   10.93% [2] 11.16% [1] 11.16% [1] 11.16% [1] 11.16% [1] 10.93% [2] 10.93% [2] 10.93% [2] 10.93% [2]
Total first lien senior secured loans $ 0.8 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.8 [3],[4]   0.8 [6],[7]                
Investment, Identifier [Axis]: Sundance Group Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.18%     11.18% 11.18% 11.18% 11.18%        
Total first lien senior secured loans [3],[4] $ 0.3                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.3                    
Investment, Identifier [Axis]: Sunk Rock Foundry Partners LP, Hatteras Electrical Manufacturing Holding Company and Sigma Electric Manufacturing Corporation, Diecast Beacon                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.0   6.0                
Less: funded commitments (0.3)   (0.6)                
Total unfunded commitments 5.7   5.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 5.7   5.4                
Investment, Identifier [Axis]: Sunk Rock Foundry Partners LP, Hatteras Electrical Manufacturing Holding Company and Sigma Electric Manufacturing Corporation, Diecast Beacon, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [15]     0.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [16]   $ 0.0 [15]                
Investment, Identifier [Axis]: Sunrun Atlas Depositor 2019-2, LLC and Sunrun Atlas Holdings 2019-2, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 3.61% [1]   3.61% [2] 3.61% [1] 3.61% [1] 3.61% [1] 3.61% [1] 3.61% [2] 3.61% [2] 3.61% [2] 3.61% [2]
Total first lien senior secured loans $ 0.1 [4]   $ 0.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [4]   $ 0.1 [7]                
Investment, Identifier [Axis]: Sunrun Atlas Depositor 2019-2, LLC and Sunrun Atlas Holdings 2019-2, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon 11.55% [1]   11.16% [2] 11.55% [1] 11.55% [1] 11.55% [1] 11.55% [1] 11.16% [2] 11.16% [2] 11.16% [2] 11.16% [2]
Total first lien senior secured loans $ 150.3 [3],[4]   $ 147.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 138.3 [3],[4]   136.1 [6],[7]                
Investment, Identifier [Axis]: Sunrun Luna Holdco 2021, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 75.0   75.0                
Less: funded commitments (65.3)   (40.7)                
Total unfunded commitments 9.7   34.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.7   $ 34.3                
Investment, Identifier [Axis]: Sunrun Luna Holdco 2021, LLC, Senior subordinated revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.15% [1]   7.86% [2] 10.15% [1] 10.15% [1] 10.15% [1] 10.15% [1] 7.86% [2] 7.86% [2] 7.86% [2] 7.86% [2]
Total first lien senior secured loans $ 65.3 [4],[5]   $ 24.4 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 64.0 [4],[5]   $ 24.2 [7],[8]                
Investment, Identifier [Axis]: Sunrun Luna Holdco 2021, LLC, Senior subordinated revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     8.95%         8.95% 8.95% 8.95% 8.95%
Total first lien senior secured loans [7],[8]     $ 16.3                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7],[8]     $ 16.1                
Investment, Identifier [Axis]: Sunrun Xanadu Issuer 2019-1, LLC and Sunrun Xanadu Holdings 2019-1, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 3.98% [1]   3.98% [2] 3.98% [1] 3.98% [1] 3.98% [1] 3.98% [1] 3.98% [2] 3.98% [2] 3.98% [2] 3.98% [2]
Total first lien senior secured loans $ 0.3 [4]   $ 0.3 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [4]   $ 0.3 [7]                
Investment, Identifier [Axis]: Sunrun Xanadu Issuer 2019-1, LLC and Sunrun Xanadu Holdings 2019-1, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon 10.00% [1]   10.00% [2] 10.00% [1] 10.00% [1] 10.00% [1] 10.00% [1] 10.00% [2] 10.00% [2] 10.00% [2] 10.00% [2]
Total first lien senior secured loans $ 73.7 [3],[4]   $ 72.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 68.6 [3],[4]   67.3 [6],[7]                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.0   7.0                
Less: funded commitments 0.0   (3.1)                
Total unfunded commitments 7.0   3.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 7.0   $ 3.9                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.28% [1]   8.69% [2] 9.28% [1] 9.28% [1] 9.28% [1] 9.28% [1] 8.69% [2] 8.69% [2] 8.69% [2] 8.69% [2]
Total first lien senior secured loans $ 12.3 [3],[4]   $ 12.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.0 [3],[4]   $ 10.5 [6],[7]                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.25%         10.25% 10.25% 10.25% 10.25%
Total first lien senior secured loans [7]     $ 3.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7]     $ 2.6                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.65% [1]   12.07% [2] 12.65% [1] 12.65% [1] 12.65% [1] 12.65% [1] 12.07% [2] 12.07% [2] 12.07% [2] 12.07% [2]
Total first lien senior secured loans $ 76.2 [3],[4]   $ 76.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 68.6 [3],[4]   64.8 [6],[7]                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., Series C-1 preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 79.0 [4]   73.1 [7]                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., Series C-2 preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 39.6 [4]   36.6 [7]                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., Series C-3 preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 15.4 [4]   14.3 [7]                
Investment, Identifier [Axis]: Synergy HomeCare Franchising, LLC and NP/Synergy Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.2   4.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.2   4.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 4.2   4.2                
Investment, Identifier [Axis]: Synergy HomeCare Franchising, LLC and NP/Synergy Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0   $ 1.0                
Investment, Identifier [Axis]: Synergy HomeCare Franchising, LLC and NP/Synergy Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   10.48% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 13.1 [3],[4]   $ 13.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 13.1 [3],[4]   13.1 [6],[7]                
Investment, Identifier [Axis]: Systems Planning and Analysis Inc.., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.76%     10.76% 10.76% 10.76% 10.76%        
Total first lien senior secured loans [3],[4] $ 1.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 1.0                    
Investment, Identifier [Axis]: Systems Planning and Analysis Inc.., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.10%     11.10% 11.10% 11.10% 11.10%        
Total first lien senior secured loans [3],[4] $ 1.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 1.1                    
Investment, Identifier [Axis]: Systems Planning and Analysis, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0                    
Less: funded commitments (1.1)                    
Total unfunded commitments 2.9                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 2.9                    
Investment, Identifier [Axis]: TA/WEG Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.0   2.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.0   2.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.0   $ 2.0                
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.81% [1]   9.98% [2] 10.81% [1] 10.81% [1] 10.81% [1] 10.81% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [7]                
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.26% [1]   9.41% [2] 11.26% [1] 11.26% [1] 11.26% [1] 11.26% [1] 9.41% [2] 9.41% [2] 9.41% [2] 9.41% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [7]                
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.00% [1]   10.75% [2] 11.00% [1] 11.00% [1] 11.00% [1] 11.00% [1] 10.75% [2] 10.75% [2] 10.75% [2] 10.75% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [7]                
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.10% [1]   10.46% [2] 11.10% [1] 11.10% [1] 11.10% [1] 11.10% [1] 10.46% [2] 10.46% [2] 10.46% [2] 10.46% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [7]                
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2   0.3                
Less: funded commitments 0.0   (0.1)                
Total unfunded commitments 0.2   0.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.2   $ 0.2                
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   9.98% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 6.5 [3],[4]   $ 34.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.5 [3],[4]   $ 34.4 [6],[7]                
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.38% [1]   9.98% [2] 10.38% [1] 10.38% [1] 10.38% [1] 10.38% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 6.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 6.5 [6],[7]                
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   9.57% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 9.57% [2] 9.57% [2] 9.57% [2] 9.57% [2]
Total first lien senior secured loans $ 34.3 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 34.3 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: THG Acquisition, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.9   18.2                
Less: funded commitments (1.0)   0.0                
Total unfunded commitments 13.9   18.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 13.9   $ 18.2                
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   9.88% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 9.88% [2] 9.88% [2] 9.88% [2] 9.88% [2]
Total first lien senior secured loans $ 20.4 [3],[4]   $ 17.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 20.0 [16]   $ 16.7 [6],[7]                
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 14.8 [3],[4]   $ 14.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.7 [3],[4]   $ 14.7 [6],[7]                
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.59% [1]   10.13% [2] 10.59% [1] 10.59% [1] 10.59% [1] 10.59% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.59%     10.59% 10.59% 10.59% 10.59%        
Total first lien senior secured loans [3],[4] $ 1.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 1.0                    
Investment, Identifier [Axis]: Tamarack Intermediate, L.L.C. and Tamarack Parent, L.L.C.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5                
Less: funded commitments (1.2)   (1.3)                
Total unfunded commitments 6.3   6.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.3   6.2                
Investment, Identifier [Axis]: Tamarack Intermediate, L.L.C. and Tamarack Parent, L.L.C., Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.8   $ 5.9                
Investment, Identifier [Axis]: Tamarack Intermediate, L.L.C. and Tamarack Parent, L.L.C., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.76% [1]   9.48% [2] 10.76% [1] 10.76% [1] 10.76% [1] 10.76% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 35.0 [3]   $ 35.1 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 35.0 [3]   $ 35.1 [6]                
Investment, Identifier [Axis]: Tamarack Intermediate, L.L.C. and Tamarack Parent, L.L.C., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.37% [1]   10.17% [2] 10.37% [1] 10.37% [1] 10.37% [1] 10.37% [1] 10.17% [2] 10.17% [2] 10.17% [2] 10.17% [2]
Total first lien senior secured loans $ 1.2 [3],[4]   $ 1.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.2 [3],[4]   1.3 [6],[7]                
Investment, Identifier [Axis]: Taymax Group, L.P., Taymax Group G.P., LLC, PF Salem Canada ULC and TCP Fit Parent, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.7   1.7                
Less: funded commitments (1.1)   (0.8)                
Total unfunded commitments 0.6   0.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 0.6   0.9                
Investment, Identifier [Axis]: Taymax Group, L.P., Taymax Group G.P., LLC, PF Salem Canada ULC and TCP Fit Parent, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.7   $ 4.6                
Investment, Identifier [Axis]: Taymax Group, L.P., Taymax Group G.P., LLC, PF Salem Canada ULC and TCP Fit Parent, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.63% [1]   8.92% [2] 10.63% [1] 10.63% [1] 10.63% [1] 10.63% [1] 8.92% [2] 8.92% [2] 8.92% [2] 8.92% [2]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 1.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3 [3],[4]   $ 1.4 [6],[7]                
Investment, Identifier [Axis]: Taymax Group, L.P., Taymax Group G.P., LLC, PF Salem Canada ULC and TCP Fit Parent, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.64% [1]   9.51% [2] 10.64% [1] 10.64% [1] 10.64% [1] 10.64% [1] 9.51% [2] 9.51% [2] 9.51% [2] 9.51% [2]
Total first lien senior secured loans $ 1.1 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.1 [3],[4]   $ 0.4 [6],[7]                
Investment, Identifier [Axis]: Taymax Group, L.P., Taymax Group G.P., LLC, PF Salem Canada ULC and TCP Fit Parent, L.P., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.67% [1]   10.05% [2] 10.67% [1] 10.67% [1] 10.67% [1] 10.67% [1] 10.05% [2] 10.05% [2] 10.05% [2] 10.05% [2]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 0.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [3],[4]   $ 0.4 [6],[7]                
Investment, Identifier [Axis]: Teasdale Foods, Inc. and Familia Group Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 12.29% [1]   12.29% [2] 12.29% [1] 12.29% [1] 12.29% [1] 12.29% [1] 12.29% [2] 12.29% [2] 12.29% [2] 12.29% [2]
Total first lien senior secured loans $ 76.1 [3],[4]   $ 75.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 68.5 [3],[4]   65.3 [6],[7]                
Investment, Identifier [Axis]: Teasdale Foods, Inc. and Familia Group Holdings Inc., Warrant to purchase up to 57,827 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.5   $ 0.0                
Investment, Identifier [Axis]: Tempus Labs, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   10.49% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 10.49% [2] 10.49% [2] 10.49% [2] 10.49% [2]
Total first lien senior secured loans $ 71.4 [3],[4]   $ 71.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 71.4 [3],[4]   69.6 [6],[7]                
Investment, Identifier [Axis]: TerSera Therapeutics LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.1   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.1   $ 0.1                
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.44% [1]   9.98% [2] 10.44% [1] 10.44% [1] 10.44% [1] 10.44% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 5.0 [3],[4]   $ 5.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.0 [3],[4]   $ 5.0 [6],[7]                
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.44% [1]   9.98% [2] 10.44% [1] 10.44% [1] 10.44% [1] 10.44% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 2.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.0 [3],[4]   $ 2.0 [6],[7]                
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.44% [1]   9.98% [2] 10.44% [1] 10.44% [1] 10.44% [1] 10.44% [1] 9.98% [2] 9.98% [2] 9.98% [2] 9.98% [2]
Total first lien senior secured loans $ 1.8 [3],[4]   $ 1.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.8 [3],[4]   1.8 [6],[7]                
Investment, Identifier [Axis]: The Alaska Club Partners, LLC, Athletic Club Partners LLC and The Alaska Club, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.1   1.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 1.1   1.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 1.1   $ 1.1                
Investment, Identifier [Axis]: The Alaska Club Partners, LLC, Athletic Club Partners LLC and The Alaska Club, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 13.50% [1]   14.00% [2] 13.50% [1] 13.50% [1] 13.50% [1] 13.50% [1] 14.00% [2] 14.00% [2] 14.00% [2] 14.00% [2]
Total first lien senior secured loans $ 12.5 [3],[4]   $ 12.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 12.5 [3],[4]   12.5 [6],[7]                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.6   12.6                
Less: funded commitments (7.5)   (11.5)                
Total unfunded commitments 5.1   1.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 5.1   1.1                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.5   $ 8.5                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, Class C units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] $ 0.6                    
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.15% [1]   9.57% [2] 11.15% [1] 11.15% [1] 11.15% [1] 11.15% [1] 9.57% [2] 9.57% [2] 9.57% [2] 9.57% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.19% [1]   11.08% [2] 11.19% [1] 11.19% [1] 11.19% [1] 11.19% [1] 11.08% [2] 11.08% [2] 11.08% [2] 11.08% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.14% [1]   10.10% [2] 11.14% [1] 11.14% [1] 11.14% [1] 11.14% [1] 10.10% [2] 10.10% [2] 10.10% [2] 10.10% [2]
Total first lien senior secured loans $ 3.3 [3],[4]   $ 8.9 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.3 [3],[4]   $ 8.8 [6],[7]                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.36% [1]   12.50% [2] 11.36% [1] 11.36% [1] 11.36% [1] 11.36% [1] 12.50% [2] 12.50% [2] 12.50% [2] 12.50% [2]
Total first lien senior secured loans $ 2.7 [3],[4]   $ 2.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 2.7 [3],[4]   $ 2.5 [6],[7]                
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, First lien senior secured revolving loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 13.25%     13.25% 13.25% 13.25% 13.25%        
Total first lien senior secured loans [3],[4] $ 1.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 1.4                    
Investment, Identifier [Axis]: The Edelman Financial Center, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 8.59%     8.59% 8.59% 8.59% 8.59%        
Total first lien senior secured loans [3],[4],[5] $ 0.5                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[5] $ 0.5                    
Investment, Identifier [Axis]: The Edelman Financial Center, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.59% [1]   11.13% [2] 11.59% [1] 11.59% [1] 11.59% [1] 11.59% [1] 11.13% [2] 11.13% [2] 11.13% [2] 11.13% [2]
Total first lien senior secured loans $ 15.8 [4],[5]   $ 13.4 [7],[8],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 14.7 [4],[5]   12.0 [7],[8],[12]                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.7                
Less: funded commitments 0.0   (0.1)                
Total unfunded commitments 1.5   1.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 1.5   1.6                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [4],[5]   $ 0.0 [8]                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.53% [1]   10.51% [2] 10.53% [1] 10.53% [1] 10.53% [1] 10.53% [1] 10.51% [2] 10.51% [2] 10.51% [2] 10.51% [2]
Total first lien senior secured loans $ 3.7 [3],[4],[5]   $ 3.5 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.7 [3],[4],[5]   $ 3.4 [7],[8]                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     12.00%         12.00% 12.00% 12.00% 12.00%
Total first lien senior secured loans [7],[8]     $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [7],[8]     0.1                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 3.1 [4],[5]   3.0 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.9 [4],[5]   2.9 [7],[8]                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC, Series A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.3 [4],[5]   4.8 [7],[8]                
Investment, Identifier [Axis]: The NPD Group, L.P., IRI Group Holdings, Inc., Information Resources, Inc. and IRI-NPD Co-Invest Aggregator, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.4   14.4                
Less: funded commitments (2.1)   (1.8)                
Total unfunded commitments 12.3   12.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 12.3   12.6                
Investment, Identifier [Axis]: The NPD Group, L.P., IRI Group Holdings, Inc., Information Resources, Inc. and IRI-NPD Co-Invest Aggregator, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 15.7 [4]   $ 15.7 [7]                
Investment, Identifier [Axis]: The NPD Group, L.P., IRI Group Holdings, Inc., Information Resources, Inc. and IRI-NPD Co-Invest Aggregator, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 10.95% [1]   10.43% [2] 10.95% [1] 10.95% [1] 10.95% [1] 10.95% [1] 10.43% [2] 10.43% [2] 10.43% [2] 10.43% [2]
Total first lien senior secured loans $ 214.5 [3],[4]   $ 213.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 210.2 [3],[4]   $ 209.3 [6],[7]                
Investment, Identifier [Axis]: The NPD Group, L.P., IRI Group Holdings, Inc., Information Resources, Inc. and IRI-NPD Co-Invest Aggregator, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.49% [1]   10.07% [2] 10.49% [1] 10.49% [1] 10.49% [1] 10.49% [1] 10.07% [2] 10.07% [2] 10.07% [2] 10.07% [2]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 1.7 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.0 [3],[4]   1.7 [6],[7],[14]                
Investment, Identifier [Axis]: The Teaching Company Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: The Teaching Company Holdings, Inc., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.4 [4]   2.5 [7]                
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.9   6.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 6.9   6.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 6.9   6.9                
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.2   3.1                
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP, Class A units 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP, Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP, Class B units 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.75% [1]   9.23% [2] 9.75% [1] 9.75% [1] 9.75% [1] 9.75% [1] 9.23% [2] 9.23% [2] 9.23% [2] 9.23% [2]
Total first lien senior secured loans $ 37.3 [3],[4]   $ 37.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 36.6 [3],[4]   $ 36.7 [7]                
Investment, Identifier [Axis]: Therapy Brands Holdings LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.53% [1]   11.10% [2] 11.53% [1] 11.53% [1] 11.53% [1] 11.53% [1] 11.10% [2] 11.10% [2] 11.10% [2] 11.10% [2]
Total first lien senior secured loans $ 29.1 [3],[4]   $ 29.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 27.9 [3],[4]   27.9 [6],[7]                
Investment, Identifier [Axis]: Thermostat Purchaser III, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.7   11.7                
Less: funded commitments (0.2)   0.0                
Total unfunded commitments 11.5   11.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 11.5   $ 11.7                
Investment, Identifier [Axis]: Thermostat Purchaser III, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [16] 0.0                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [16] $ 0.0                    
Investment, Identifier [Axis]: Thermostat Purchaser III, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.20% [1]   11.98% [2] 12.20% [1] 12.20% [1] 12.20% [1] 12.20% [1] 11.98% [2] 11.98% [2] 11.98% [2] 11.98% [2]
Total first lien senior secured loans $ 23.0 [3],[4]   $ 23.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 22.1 [3],[4]   22.1 [6],[7]                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.0   19.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 19.0   19.0                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 19.0   $ 19.0                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P., First lien secured notes                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.50% [1]   650.00% [2] 6.50% [1] 6.50% [1] 6.50% [1] 6.50% [1] 650.00% [2] 650.00% [2] 650.00% [2] 650.00% [2]
Total first lien senior secured loans $ 88.9 [4],[11]   $ 88.9 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 78.4 [4],[11]   $ 74.9 [7],[12]                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.50% [1]   9.18% [2] 9.50% [1] 9.50% [1] 9.50% [1] 9.50% [1] 9.18% [2] 9.18% [2] 9.18% [2] 9.18% [2]
Total first lien senior secured loans $ 10.9 [3],[4],[11]   $ 10.9 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.8 [3],[4],[11]   9.7 [6],[7],[12]                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P., Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.6 [4]   $ 10.7 [7]                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.00% [1]   9.00% [2] 9.00% [1] 9.00% [1] 9.00% [1] 9.00% [1] 9.00% [2] 9.00% [2] 9.00% [2] 9.00% [2]
Total first lien senior secured loans $ 85.3 [3],[4]   $ 85.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 68.2 [3],[4]   69.9 [6],[7]                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P., Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 153.7 [3],[4]   143.1 [7]                
Investment, Identifier [Axis]: Top Five Largest Portfolio Company Investments | Senior Direct Lending Program                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 1,644.0   1,631.0                
Investment, Identifier [Axis]: Totes Isotoner Corporation and Totes Ultimate Holdco, Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   0.0                
Redemptions (cost) 0.0   0.0                
Sales (cost) 0.0   0.0                
Interest income 0.1   0.3                
Capital structuring service fees 0.0   0.0                
Dividend income 0.0   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): 0.1   (0.2)                
Fair Value 3.8   3.7                
Investment, Identifier [Axis]: Totes Isotoner Corporation and Totes Ultimate Holdco, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.3   $ 0.2 [7]                
Investment, Identifier [Axis]: Totes Isotoner Corporation and Totes Ultimate Holdco, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.84% [1]   10.38% [2] 10.84% [1] 10.84% [1] 10.84% [1] 10.84% [1] 10.38% [2] 10.38% [2] 10.38% [2] 10.38% [2]
Total first lien senior secured loans $ 2.2 [3],[4]   $ 2.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.9 [3],[4]   $ 1.9 [6],[7]                
Investment, Identifier [Axis]: Totes Isotoner Corporation and Totes Ultimate Holdco, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.84% [1]   8.38% [2] 8.84% [1] 8.84% [1] 8.84% [1] 8.84% [1] 8.38% [2] 8.38% [2] 8.38% [2] 8.38% [2]
Total first lien senior secured loans $ 1.6 [3],[4]   $ 1.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 1.6 [3],[4]   1.6 [6],[7]                
Investment, Identifier [Axis]: Touchstone Acquisition, Inc. and Touchstone Holding, L.P., Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [4]   2.1 [7]                
Investment, Identifier [Axis]: Trader Corporation and Project Auto Finco Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   3.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.6   3.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.6   $ 3.6                
Investment, Identifier [Axis]: Trader Corporation and Project Auto Finco Corp.., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.68% [1]   11.40% [2] 11.68% [1] 11.68% [1] 11.68% [1] 11.68% [1] 11.40% [2] 11.40% [2] 11.40% [2] 11.40% [2]
Total first lien senior secured loans $ 12.2 [3],[4],[5]   $ 12.2 [6],[7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 11.9 [3],[4],[5]   $ 11.9 [6],[7],[8]                
Investment, Identifier [Axis]: Triton Water Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.66% [1]   8.23% [2] 8.66% [1] 8.66% [1] 8.66% [1] 8.66% [1] 8.23% [2] 8.23% [2] 8.23% [2] 8.23% [2]
Total first lien senior secured loans $ 1.0 [3],[4],[11]   $ 1.0 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.9 [3],[4],[11]   $ 0.9 [6],[7],[12]                
Investment, Identifier [Axis]: Triton Water Holdings, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.25% [1]   625.00% [2] 6.25% [1] 6.25% [1] 6.25% [1] 6.25% [1] 625.00% [2] 625.00% [2] 625.00% [2] 625.00% [2]
Total first lien senior secured loans $ 0.1 [4],[11]   $ 0.1 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [4],[11]   0.1 [7],[12]                
Investment, Identifier [Axis]: Two Six Labs, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.3   10.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 10.3   10.3                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 10.3   10.3                
Investment, Identifier [Axis]: U.S. Anesthesia Partners, Inc. & U.S. Anesthesia Partners Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.7 [4]   $ 12.7 [7]                
Investment, Identifier [Axis]: U.S. Anesthesia Partners, Inc. & U.S. Anesthesia Partners Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.16% [1]   11.62% [2] 12.16% [1] 12.16% [1] 12.16% [1] 12.16% [1] 11.62% [2] 11.62% [2] 11.62% [2] 11.62% [2]
Total first lien senior secured loans $ 147.8 [3],[4]   $ 147.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 141.9 [3],[4]   143.3 [6],[7]                
Investment, Identifier [Axis]: UKG Inc. and H&F Unite Partners, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 25.0   25.0                
Less: funded commitments (11.0)   (10.8)                
Total unfunded commitments 14.0   14.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 14.0   $ 14.2                
Investment, Identifier [Axis]: UKG Inc. and H&F Unite Partners, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.56% [1]   8.06% [2] 8.56% [1] 8.56% [1] 8.56% [1] 8.56% [1] 8.06% [2] 8.06% [2] 8.06% [2] 8.06% [2]
Total first lien senior secured loans $ 10.9 [4],[5],[13]   $ 10.6 [7],[8],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 10.6 [4],[5],[13]   10.6 [7],[8],[14]                
Investment, Identifier [Axis]: UKG Inc. and H&F Unite Partners, L.P., Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 15.4 [4],[5]   14.4 [7],[8]                
Investment, Identifier [Axis]: US Salt Investors, LLC and Emerald Lake Pearl Acquisition-A, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.9   9.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 9.9   9.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 9.9   $ 9.9                
Investment, Identifier [Axis]: US Salt Investors, LLC and Emerald Lake Pearl Acquisition-A, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.34% [1]   10.23% [2] 10.34% [1] 10.34% [1] 10.34% [1] 10.34% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 26.3 [3],[4]   $ 26.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 25.0 [3],[4]   25.3 [6],[7]                
Investment, Identifier [Axis]: US Salt Investors, LLC and Emerald Lake Pearl Acquisition-A, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.5 [4]   0.5 [7]                
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     18.4                
Less: funded commitments     0.0                
Total unfunded commitments     18.4                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     $ 18.4                
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC and Koln Co-Invest Unblocked, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.6                    
Less: funded commitments 0.0                    
Total unfunded commitments 8.6                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 8.6                    
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC and Koln Co-Invest Unblocked, LP, Class A Interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [4] $ 4.6                    
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC and Koln Co-Invest Unblocked, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.64%     11.64% 11.64% 11.64% 11.64%        
Total first lien senior secured loans [3],[4] $ 10.4                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 10.1                    
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.38%         9.38% 9.38% 9.38% 9.38%
Total first lien senior secured loans [6],[7]     $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     1.0                
Investment, Identifier [Axis]: UserZoom Technologies, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 11.63%     11.63% 11.63% 11.63% 11.63%        
Total first lien senior secured loans [3],[4] $ 5.8                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 5.7                    
Investment, Identifier [Axis]: VCP-EDC Co-Invest, LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.2   4.2                
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.6   8.7                
Less: funded commitments (0.2)   0.0                
Total unfunded commitments 7.4   8.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 7.4   8.7                
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 8.2 [4]   $ 8.6 [7]                
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., Class A-2 units 2                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0                    
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.60% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.60% [2] 10.60% [2] 10.60% [2] 10.60% [2]
Total first lien senior secured loans $ 4.2 [3],[13]   $ 6.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.1 [3],[13]   $ 6.0 [6],[7]                
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.06% [1]   10.52% [2] 11.06% [1] 11.06% [1] 11.06% [1] 11.06% [1] 10.52% [2] 10.52% [2] 10.52% [2] 10.52% [2]
Total first lien senior secured loans $ 6.2 [3],[4]   $ 3.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 6.1 [3],[4]   3.1 [6],[7]                
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 13.25%     13.25% 13.25% 13.25% 13.25%        
Total first lien senior secured loans [3],[4] $ 0.2                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] 0.2                    
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost) 0.0   6.0                
Redemptions (cost) 0.0   4.5                
Sales (cost) 0.0   0.0                
Interest income 1.5   5.0                
Capital structuring service fees 0.0   0.2                
Dividend income 6.7   0.0                
Other income 0.0   0.0                
Net realized gains (losses): 0.0   0.0                
Net unrealized gains (losses): (5.4)   33.5                
Fair Value 110.7   116.1                
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 68.0 [4]   $ 73.4 [7]                
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.16% [1]   13.62% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.62% [2] 13.62% [2] 13.62% [2] 13.62% [2]
Total first lien senior secured loans $ 27.3 [3],[4]   $ 27.3 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 27.3 [3],[4]   $ 27.3 [7]                
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.16% [1]   13.62% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.62% [2] 13.62% [2] 13.62% [2] 13.62% [2]
Total first lien senior secured loans $ 9.4 [3],[4]   $ 9.4 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 9.4 [3],[4]   $ 9.4 [7]                
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.16% [1]   13.62% [2] 14.16% [1] 14.16% [1] 14.16% [1] 14.16% [1] 13.62% [2] 13.62% [2] 13.62% [2] 13.62% [2]
Total first lien senior secured loans $ 6.0 [3],[4]   $ 6.0 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.0 [3],[4]   6.0 [7]                
Investment, Identifier [Axis]: VRC Companies, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.4   5.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.4   5.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 5.4   $ 5.4                
Investment, Identifier [Axis]: VRC Companies, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     10.97%         10.97% 10.97% 10.97% 10.97%
Total first lien senior secured loans [6],[7]     $ 0.0                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     $ 0.0                
Investment, Identifier [Axis]: VRC Companies, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon 12.00% [1]   12.00% [2] 12.00% [1] 12.00% [1] 12.00% [1] 12.00% [1] 12.00% [2] 12.00% [2] 12.00% [2] 12.00% [2]
Total first lien senior secured loans $ 5.1 [4]   $ 5.0 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 4.8 [4]   4.7 [7]                
Investment, Identifier [Axis]: VS Buyer, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.1   8.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.1   8.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 8.1   8.1                
Investment, Identifier [Axis]: VSC Investors LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.5 [4],[5],[11]   0.5 [7],[8],[12]                
Investment, Identifier [Axis]: Varsity Brands Holding Co., Inc. and BCPE Hercules Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.0 [4]   $ 1.0 [7]                
Investment, Identifier [Axis]: Varsity Brands Holding Co., Inc. and BCPE Hercules Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.87% [1]   7.88% [2] 9.87% [1] 9.87% [1] 9.87% [1] 9.87% [1] 7.88% [2] 7.88% [2] 7.88% [2] 7.88% [2]
Total first lien senior secured loans $ 14.7 [3],[4],[11]   $ 14.8 [6],[7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 13.7 [3],[4],[11]   $ 14.2 [6],[7],[12]                
Investment, Identifier [Axis]: Varsity Brands Holding Co., Inc. and BCPE Hercules Holdings, LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 15.17% [1]   12.63% [2] 15.17% [1] 15.17% [1] 15.17% [1] 15.17% [1] 12.63% [2] 12.63% [2] 12.63% [2] 12.63% [2]
Total first lien senior secured loans $ 144.1 [3],[4]   $ 122.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 141.3 [3],[4]   $ 121.5 [6],[7]                
Investment, Identifier [Axis]: Varsity Brands Holding Co., Inc. and BCPE Hercules Holdings, LP, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     12.63%         12.63% 12.63% 12.63% 12.63%
Total first lien senior secured loans [6],[7]     $ 21.1                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     20.9                
Investment, Identifier [Axis]: Verista, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.2   8.2                
Less: funded commitments (2.4)   (1.1)                
Total unfunded commitments 5.8   7.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 5.8   $ 7.1                
Investment, Identifier [Axis]: Verista, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.89% [1]   10.19% [2] 10.89% [1] 10.89% [1] 10.89% [1] 10.89% [1] 10.19% [2] 10.19% [2] 10.19% [2] 10.19% [2]
Total first lien senior secured loans $ 0.8 [3],[4]   $ 0.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.8 [3],[4]   $ 0.8 [6],[7]                
Investment, Identifier [Axis]: Verista, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.75% [1]   10.27% [2] 10.75% [1] 10.75% [1] 10.75% [1] 10.75% [1] 10.27% [2] 10.27% [2] 10.27% [2] 10.27% [2]
Total first lien senior secured loans $ 2.4 [3],[4]   $ 1.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.4 [3],[4]   1.1 [6],[7]                
Investment, Identifier [Axis]: Verscend Holding Corp.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.5   22.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 22.5   22.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 22.5   22.5                
Investment, Identifier [Axis]: Vertice Pharma UK Parent Limited, Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.0 [5]   $ 0.0 [8]                
Investment, Identifier [Axis]: Viant Medical Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.59% [1]   8.13% [2] 8.59% [1] 8.59% [1] 8.59% [1] 8.59% [1] 8.13% [2] 8.13% [2] 8.13% [2] 8.13% [2]
Total first lien senior secured loans $ 5.8 [4],[11]   $ 3.2 [7],[12]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.4 [4],[11]   $ 2.8 [7],[12]                
Investment, Identifier [Axis]: Visual Edge Technology, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon 11.96% [1]   11.74% [2] 11.96% [1] 11.96% [1] 11.96% [1] 11.96% [1] 11.74% [2] 11.74% [2] 11.74% [2] 11.74% [2]
Total first lien senior secured loans $ 32.6 [3],[4]   $ 32.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 29.4 [3],[4]   29.3 [6],[7]                
Investment, Identifier [Axis]: Visual Edge Technology, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 108.0 [4],[9]   103.8 [7],[10]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 48.5 [4],[9]   48.8 [7],[10]                
Investment, Identifier [Axis]: Visual Edge Technology, Inc., Warrant to purchase up to 10,358,572 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0   0.0                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 33.8   35.4                
Less: funded commitments (13.7)   (9.6)                
Total unfunded commitments 20.1   25.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 20.1   25.8                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.9   $ 4.4                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 33.0 [3],[4]   $ 33.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 32.3 [3],[4]   $ 32.4 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 14.5 [3],[4]   $ 14.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.2 [3],[4]   $ 14.2 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 10.7 [3],[4]   $ 11.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 10.5 [3],[4]   $ 11.0 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.29% [1]   10.98% [2] 11.29% [1] 11.29% [1] 11.29% [1] 11.29% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 12.9 [3],[4]   $ 10.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.6 [3],[4]   $ 10.5 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 4.5 [3],[4]   $ 4.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.4 [3],[4]   $ 4.4 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 6                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan 7                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.30% [1]   10.98% [2] 11.30% [1] 11.30% [1] 11.30% [1] 11.30% [1] 10.98% [2] 10.98% [2] 10.98% [2] 10.98% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.28% [1]   10.32% [2] 11.28% [1] 11.28% [1] 11.28% [1] 11.28% [1] 10.32% [2] 10.32% [2] 10.32% [2] 10.32% [2]
Total first lien senior secured loans $ 12.7 [3],[4],[13]   $ 8.6 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 12.4 [3],[4],[13]   $ 8.4 [6],[7],[14]                
Investment, Identifier [Axis]: Walnut Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.46% [1]   10.24% [2] 10.46% [1] 10.46% [1] 10.46% [1] 10.46% [1] 10.24% [2] 10.24% [2] 10.24% [2] 10.24% [2]
Total first lien senior secured loans $ 14.6 [3],[4]   $ 14.7 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 14.2 [3],[4]   $ 14.2 [6],[7]                
Investment, Identifier [Axis]: Walnut Parent, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.46% [1]   10.24% [2] 10.46% [1] 10.46% [1] 10.46% [1] 10.46% [1] 10.24% [2] 10.24% [2] 10.24% [2] 10.24% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: Wand Newco 3, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.09% [1]   11.63% [2] 12.09% [1] 12.09% [1] 12.09% [1] 12.09% [1] 11.63% [2] 11.63% [2] 11.63% [2] 11.63% [2]
Total first lien senior secured loans $ 182.6 [4]   $ 182.6 [7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 182.6 [4]   $ 178.9 [7]                
Investment, Identifier [Axis]: Wash Encore Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.85% [1]   9.12% [2] 10.85% [1] 10.85% [1] 10.85% [1] 10.85% [1] 9.12% [2] 9.12% [2] 9.12% [2] 9.12% [2]
Total first lien senior secured loans $ 98.3 [3],[4]   $ 98.5 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 96.3 [3],[4]   96.5 [6],[7]                
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments     0.7                
Less: funded commitments     0.0                
Total unfunded commitments     0.7                
Less: commitments substantially at discretion of the Company     0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions     0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments     0.7                
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.6   $ 3.2                
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.41% [1]   10.23% [2] 10.41% [1] 10.41% [1] 10.41% [1] 10.41% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 21.1 [3],[4]   $ 20.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 21.1 [3],[4]   20.4 [6],[7]                
Investment, Identifier [Axis]: Waverly Advisors, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2   0.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.2   0.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.2   $ 0.2                
Investment, Identifier [Axis]: Waverly Advisors, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   10.23% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 10.23% [2] 10.23% [2] 10.23% [2] 10.23% [2]
Total first lien senior secured loans $ 0.6 [3],[4],[5]   $ 0.6 [7],[8]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.6 [3],[4],[5]   0.6 [7],[8]                
Investment, Identifier [Axis]: WebPT, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9                
Less: funded commitments (0.6)   (0.3)                
Total unfunded commitments 0.3   0.6                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.3   $ 0.6                
Investment, Identifier [Axis]: WebPT, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.74% [1]   11.48% [2] 11.74% [1] 11.74% [1] 11.74% [1] 11.74% [1] 11.48% [2] 11.48% [2] 11.48% [2] 11.48% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 48.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 48.1 [6],[7]                
Investment, Identifier [Axis]: WebPT, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.62% [1]   11.26% [2] 11.62% [1] 11.62% [1] 11.62% [1] 11.62% [1] 11.26% [2] 11.26% [2] 11.26% [2] 11.26% [2]
Total first lien senior secured loans $ 0.6 [3],[4]   $ 0.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.6 [3],[4]   0.3 [6],[7]                
Investment, Identifier [Axis]: Wellness AcquisitionCo, Inc.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.9   3.9                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.9   $ 3.9                
Investment, Identifier [Axis]: Wellness AcquisitionCo, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.49% [1]   9.91% [2] 10.49% [1] 10.49% [1] 10.49% [1] 10.49% [1] 9.91% [2] 9.91% [2] 9.91% [2] 9.91% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1                
Less: funded commitments (0.8)   (1.0)                
Total unfunded commitments 3.3   3.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 3.3   $ 3.1                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   10.48% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 17.9 [3],[4]   $ 18.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 17.8 [3],[4]   $ 17.8 [6],[7]                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   10.48% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.80% [1]   10.48% [2] 10.80% [1] 10.80% [1] 10.80% [1] 10.80% [1] 10.48% [2] 10.48% [2] 10.48% [2] 10.48% [2]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.2 [3],[4]   $ 0.2 [6],[7]                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.75% [1]   10.09% [2] 12.75% [1] 12.75% [1] 12.75% [1] 12.75% [1] 10.09% [2] 10.09% [2] 10.09% [2] 10.09% [2]
Total first lien senior secured loans $ 0.7 [3],[4],[13]   $ 0.8 [6],[7],[14]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.7 [3],[4],[13]   0.8 [6],[7],[14]                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 5.3 [4]   $ 5.1 [7]                
Investment, Identifier [Axis]: Winebow Holdings, Inc. and The Vintner Group, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.09% [1]   10.63% [2] 11.09% [1] 11.09% [1] 11.09% [1] 11.09% [1] 10.63% [2] 10.63% [2] 10.63% [2] 10.63% [2]
Total first lien senior secured loans $ 27.9 [3],[4]   $ 28.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 27.4 [3],[4]   27.5 [6],[7]                
Investment, Identifier [Axis]: WorkWave Intermediate II, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.2   5.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.2   5.2                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 5.2   5.2                
Investment, Identifier [Axis]: WorkWave Intermediate II, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 69.5 [3],[4]   67.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 69.5 [3],[4]   $ 67.4 [6],[7]                
Investment, Identifier [Axis]: WorkWave Intermediate II, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     11.44%         11.44% 11.44% 11.44% 11.44%
Total first lien senior secured loans 18.2 [3],[4]   $ 17.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 18.2 [3],[4]   17.3 [6],[7]                
Investment, Identifier [Axis]: Worldwide Produce Acquisition, LLC and REP WWP Coinvest IV, L.P.                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0                    
Less: funded commitments (0.7)                    
Total unfunded commitments 3.3                    
Less: commitments substantially at discretion of the Company 0.0                    
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 3.3                    
Investment, Identifier [Axis]: Worldwide Produce Acquisition, LLC and REP WWP Coinvest IV, L.P. , Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 1.7                    
Investment, Identifier [Axis]: Worldwide Produce Acquisition, LLC and REP WWP Coinvest IV, L.P. , First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.93%     10.93% 10.93% 10.93% 10.93%        
Total first lien senior secured loans [3],[4] $ 7.5                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 7.3                    
Investment, Identifier [Axis]: Worldwide Produce Acquisition, LLC and REP WWP Coinvest IV, L.P. , First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.94%     10.94% 10.94% 10.94% 10.94%        
Total first lien senior secured loans [3],[4],[13] $ 0.7                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4],[13] 0.6                    
Investment, Identifier [Axis]: Worldwide Produce Acquisition, LLC and REP WWP Coinvest IV, L.P. 1                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2                    
Less: funded commitments 0.0                    
Total unfunded commitments 0.2                    
Less: commitments substantially at discretion of the Company 0.0                    
Total net adjusted unfunded revolving and delayed draw loan commitments 0.2                    
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.6   8.9                
Less: funded commitments (2.2)   (0.2)                
Total unfunded commitments 3.4   8.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 3.4   8.7                
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 3.5 [4]   4.2 [7]                
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.9 [4]   $ 1.1 [7]                
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.13% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 36.9 [3]   $ 37.0 [6]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 36.1 [3]   $ 36.6 [6]                
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.91% [1]   10.13% [2] 10.91% [1] 10.91% [1] 10.91% [1] 10.91% [1] 10.13% [2] 10.13% [2] 10.13% [2] 10.13% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.74% [1]   12.25% [2] 10.74% [1] 10.74% [1] 10.74% [1] 10.74% [1] 12.25% [2] 12.25% [2] 12.25% [2] 12.25% [2]
Total first lien senior secured loans $ 2.2 [3],[4]   $ 0.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 2.2 [3],[4]   0.2 [6],[7]                
Investment, Identifier [Axis]: YE Brands Holdings, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.2   2.2                
Less: funded commitments 0.0   (1.5)                
Total unfunded commitments 2.2   0.7                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 2.2   $ 0.7                
Investment, Identifier [Axis]: YE Brands Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.25% [1]   9.93% [2] 10.25% [1] 10.25% [1] 10.25% [1] 10.25% [1] 9.93% [2] 9.93% [2] 9.93% [2] 9.93% [2]
Total first lien senior secured loans $ 8.1 [3],[4]   $ 8.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 8.1 [3],[4]   $ 8.2 [6],[7]                
Investment, Identifier [Axis]: YE Brands Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.00% [1]   9.68% [2] 10.00% [1] 10.00% [1] 10.00% [1] 10.00% [1] 9.68% [2] 9.68% [2] 9.68% [2] 9.68% [2]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.1 [3],[4]   $ 0.1 [6],[7]                
Investment, Identifier [Axis]: YE Brands Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]     9.47%         9.47% 9.47% 9.47% 9.47%
Total first lien senior secured loans [6],[7]     $ 1.5                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [6],[7]     1.5                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.3   21.5                
Less: funded commitments (0.1)   (0.1)                
Total unfunded commitments 8.2   21.4                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 8.2   $ 21.4                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.85% [1]   9.48% [2] 9.85% [1] 9.85% [1] 9.85% [1] 9.85% [1] 9.48% [2] 9.48% [2] 9.48% [2] 9.48% [2]
Total first lien senior secured loans $ 13.3 [3],[4]   $ 0.1 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 13.3 [3],[4]   0.1 [6],[7]                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 0.0 [16]   0.0 [15]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 0.0 [16]   0.0 [15]                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC, Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 6.7   5.5                
Investment, Identifier [Axis]: ZBS Mechanical Group Co-Invest Fund 2, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 9.1                    
Investment, Identifier [Axis]: ZenDesk, Inc., Zoro TopCo, Inc. and Zoro TopCo, LP                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.8   16.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 12.8   16.8                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 12.8   16.8                
Investment, Identifier [Axis]: ZenDesk, Inc., Zoro TopCo, Inc. and Zoro TopCo, LP, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 3.0 [4]   $ 2.7 [7]                
Investment, Identifier [Axis]: ZenDesk, Inc., Zoro TopCo, Inc. and Zoro TopCo, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.88% [1]   11.04% [2] 11.88% [1] 11.88% [1] 11.88% [1] 11.88% [1] 11.04% [2] 11.04% [2] 11.04% [2] 11.04% [2]
Total first lien senior secured loans $ 42.4 [3],[4]   $ 42.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 41.6 [3],[4]   41.6 [6],[7]                
Investment, Identifier [Axis]: ZenDesk, Inc., Zoro TopCo, Inc. and Zoro TopCo, LP, Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 27.6 [4]   $ 26.8 [7]                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.52% [1]   11.97% [2] 12.52% [1] 12.52% [1] 12.52% [1] 12.52% [1] 11.97% [2] 11.97% [2] 11.97% [2] 11.97% [2]
Total first lien senior secured loans $ 55.8 [3],[4]   $ 55.8 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 55.2 [3],[4]   $ 55.2 [6],[7]                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.52% [1]   11.97% [2] 12.52% [1] 12.52% [1] 12.52% [1] 12.52% [1] 11.97% [2] 11.97% [2] 11.97% [2] 11.97% [2]
Total first lien senior secured loans $ 56.0 [3],[4]   $ 56.0 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 55.4 [3],[4]   $ 55.4 [6],[7]                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.52% [1]   11.97% [2] 12.52% [1] 12.52% [1] 12.52% [1] 12.52% [1] 11.97% [2] 11.97% [2] 11.97% [2] 11.97% [2]
Total first lien senior secured loans $ 24.3 [3],[4]   $ 24.3 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 24.1 [3],[4]   $ 24.1 [6],[7]                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.52% [1]   11.97% [2] 12.52% [1] 12.52% [1] 12.52% [1] 12.52% [1] 11.97% [2] 11.97% [2] 11.97% [2] 11.97% [2]
Total first lien senior secured loans $ 5.4 [3],[4]   $ 5.4 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 5.3 [3],[4]   5.3 [6],[7]                
Investment, Identifier [Axis]: eResearch Technology, Inc. and Astorg VII Co-Invest ERT                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.5   2.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.5   2.5                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments 2.5   2.5                
Investment, Identifier [Axis]: eResearch Technology, Inc. and Astorg VII Co-Invest ERT, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 4.2 [4],[5]   $ 3.7 [7],[8]                
Investment, Identifier [Axis]: eResearch Technology, Inc. and Astorg VII Co-Invest ERT, Second lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.84% [1]   12.07% [2] 12.84% [1] 12.84% [1] 12.84% [1] 12.84% [1] 12.07% [2] 12.07% [2] 12.07% [2] 12.07% [2]
Total first lien senior secured loans $ 30.6 [3],[4]   $ 30.6 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value $ 28.8 [3],[4]   $ 27.2 [6],[7]                
Investment, Identifier [Axis]: eResearch Technology, Inc. and Astorg VII Co-Invest ERT, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.84% [1]   12.38% [2] 12.84% [1] 12.84% [1] 12.84% [1] 12.84% [1] 12.38% [2] 12.38% [2] 12.38% [2] 12.38% [2]
Total first lien senior secured loans $ 17.2 [3],[4]   $ 17.2 [6],[7]                
Investments Activity And Fair Value Table [Abstract]                      
Fair Value 16.1 [3],[4]   15.3 [6],[7]                
Investment, Identifier [Axis]: n2y Holding, LLC                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1                
Less: funded commitments (0.1)   0.0                
Total unfunded commitments 0.0   0.1                
Less: commitments substantially at discretion of the Company 0.0   0.0                
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw loan commitments $ 0.0   $ 0.1                
Investment, Identifier [Axis]: n2y Holding, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1] 10.60%     10.60% 10.60% 10.60% 10.60%        
Total first lien senior secured loans [3],[4] $ 0.1                    
Investments Activity And Fair Value Table [Abstract]                      
Fair Value [3],[4] $ 0.1                    
[1] Investments without an interest rate are non-income producing.
[2] Investments without an interest rate are non-income producing.
[3] Loan includes interest rate floor feature.
[4] These assets are pledged as collateral under the Company’s or the Company’s consolidated subsidiaries’ various revolving credit facilities and, as a result, are not directly available to the creditors of the Company to satisfy any obligations of the Company other than the obligations under each of the respective facilities (see Note 5).
[5] This portfolio company is not a qualifying asset under Section 55(a) of the Investment Company Act. Under the Investment Company Act, the Company may not acquire any non-qualifying asset unless, at the time such acquisition is made, qualifying assets represent at least 70% of the Company's total assets. Pursuant to Section 55(a) of the Investment Company Act, 25% of the Company's total assets are represented by investments at fair value and other assets that are considered "non-qualifying assets" as of March 31, 2023.
[6] Loan includes interest rate floor feature.
[7] These assets are pledged as collateral under the Company’s or the Company’s consolidated subsidiaries’ various revolving credit facilities and, as a result, are not directly available to the creditors of the Company to satisfy any obligations of the Company other than the obligations under each of the respective facilities (see Note 5).
[8] This portfolio company is not a qualifying asset under Section 55(a) of the Investment Company Act. Under the Investment Company Act, the Company may not acquire any non-qualifying asset unless, at the time such acquisition is made, qualifying assets represent at least 70% of the Company's total assets. Pursuant to Section 55(a) of the Investment Company Act, 25% of the Company's total assets are represented by investments at fair value and other assets that are considered "non-qualifying assets" as of December 31, 2022.
[9] Loan was on non-accrual status as of March 31, 2023.
[10] Loan was on non-accrual status as of December 31, 2022.
[11] Other than the investments noted by this footnote, the fair value of the Company’s investments is determined using unobservable inputs that are significant to the overall fair value measurement. See Note 8 to the consolidated financial statements for more information regarding the fair value of the Company’s investments.
[12] Other than the investments noted by this footnote, the fair value of the Company’s investments is determined using unobservable inputs that are significant to the overall fair value measurement. See Note 8 to the consolidated financial statements for more information regarding the fair value of the Company’s investments.
[13] As of March 31, 2023, in addition to the amounts funded by the Company under this first lien senior secured revolving loan, there were also letters of credit issued and outstanding through a financial intermediary under the loan. See Note 7 for further information on letters of credit commitments related to certain portfolio companies.
[14] As of December 31, 2022, in addition to the amounts funded by the Company under this first lien senior secured revolving loan, there were also letters of credit issued and outstanding through a financial intermediary under the loan. See Note 7 for further information on letters of credit commitments related to certain portfolio companies.
[15] As of December 31, 2022, no amounts were funded by the Company under this first lien senior secured revolving loan; however, there were letters of credit issued and outstanding through a financial intermediary under the loan. See Note 7 for further information on letters of credit commitments related to certain portfolio companies.
[16] As of March 31, 2023, no amounts were funded by the Company under this first lien senior secured revolving loan; however, there were letters of credit issued and outstanding through a financial intermediary under the loan. See Note 7 for further information on letters of credit commitments related to certain portfolio companies.
[17] The Company sold a participating interest of approximately $80.4 in aggregate principal amount outstanding of the portfolio company’s first lien senior secured revolving loan. As the transaction did not qualify as a “true sale” in accordance with GAAP, the Company recorded a corresponding $80.4 secured borrowing, at fair value, included in “secured borrowings” in the accompanying consolidated balance sheet. As of March 31, 2023, the interest rate in effect for the secured borrowing was 12.16%.
[18] The Company sold a participating interest of approximately $79.0 in aggregate principal amount outstanding of the portfolio company’s first lien senior secured revolving loan. As the transaction did not qualify as a “true sale” in accordance with U.S. generally accepted accounting principles (“GAAP”), the Company recorded a corresponding $79.0 secured borrowing, at fair value, included in “secured borrowings” in the accompanying consolidated balance sheet. As of December 31, 2022, the interest rate in effect for the secured borrowing was 11.62%.
[19] In addition to the interest earned based on the stated interest rate of this security, the Company is entitled to receive an additional interest amount of 2.00% on $40.9 in aggregate principal amount of a “first out” tranche of the portfolio company’s senior term debt previously syndicated by the Company into “first out” and “last out” tranches, whereby the “first out” tranche will have priority as to the “last out” tranche with respect to payments of principal, interest and any other amounts due thereunder.
[20] In addition to the interest earned based on the stated interest rate of this security, the Company is entitled to receive an additional interest amount of 2.00% on $40.9 in aggregate principal amount of a “first out” tranche of the portfolio company’s senior term debt previously syndicated by the Company into “first out” and “last out” tranches, whereby the “first out” tranche will have priority as to the “last out” tranche with respect to payments of principal, interest and any other amounts due thereunder.
[21] In addition to the interest earned based on the stated contractual interest rate of this security, the certificates entitle the holders thereof to receive a portion of the excess cash flow from the SDLP’s loan portfolio, after expenses, which may result in a return to the Company greater than the contractual stated interest rate.