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CONSOLIDATED SCHEDULE OF INVESTMENTS - (Parenthetical)
€ in Millions, £ in Millions, $ in Millions, $ in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2022
USD ($)
Rate
Sep. 30, 2021
USD ($)
Sep. 30, 2022
USD ($)
Rate
Sep. 30, 2021
USD ($)
Dec. 31, 2021
USD ($)
Rate
Sep. 30, 2022
CAD ($)
Rate
Sep. 30, 2022
EUR (€)
Rate
Sep. 30, 2022
GBP (£)
Rate
Dec. 31, 2021
CAD ($)
Rate
Dec. 31, 2021
EUR (€)
Rate
Dec. 31, 2021
GBP (£)
Rate
Derivative Instruments Table [Abstract]                      
Derivative Asset, Counterparty Name [Extensible Enumeration] Royal Bank of Canada [Member]   Royal Bank of Canada [Member]   Truist Financial Corporation [Member] Royal Bank of Canada [Member] Royal Bank of Canada [Member] Royal Bank of Canada [Member] Truist Financial Corporation [Member] Truist Financial Corporation [Member] Truist Financial Corporation [Member]
Derivatives $ (40.0)   $ (40.0)   $ (12.0)            
Schedule of Investments [Line Items]                      
% of Net Assets 226.18%   226.18%   225.65% 226.18% 226.18% 226.18% 225.65% 225.65% 225.65%
% of Total Assets 97.00%   97.00%   96.00% 97.00% 97.00% 97.00% 96.00% 96.00% 96.00%
% of Total Assets, non-qualifying assets 23.00%   23.00%   16.00% 23.00% 23.00% 23.00% 16.00% 16.00% 16.00%
Coupon | Rate [1]         9.50%       9.50% 9.50% 9.50%
Secured borrowings $ 79.0   $ 79.0   $ 74.0            
Net unrealized gain (loss) for federal tax purposes (500.0)   (500.0)   100.0            
Tax cost basis 21,300.0   21,300.0   19,900.0            
Aggregate gross unrealized loss for federal tax purposes 1,300.0   1,300.0   700.0            
Aggregate gross unrealized gain for federal tax purposes 800.0   800.0   800.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 21,338.5   21,338.5   20,009.5            
Revolving and delayed draw loan commitments                      
Schedule of Investments [Line Items]                      
Other commitment 3,205.0   3,205.0   2,733.0            
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3,205.4   3,205.4   2,732.5            
Less: funded commitments (520.3)   (520.3)   (352.3)            
Total unfunded commitments 2,685.1   2,685.1   2,380.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   (3.9)            
Total net adjusted unfunded revolving and delayed draw commitments 2,685.1   2,685.1   2,376.3            
Private equity commitments                      
Schedule of Investments [Line Items]                      
Other commitment 116.0   116.0   111.0            
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 115.8   115.8   110.9            
Less: funded commitments (65.6)   (65.6)   (67.6)            
Total unfunded commitments 50.2   50.2   43.3            
Less: commitments substantially at discretion of the Company (50.2)   (50.2)   (43.3)            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   0.0   0.0            
Unfunded commitments                      
Schedule of Investments [Line Items]                      
Other commitment 2,685.0   2,685.0   2,381.0            
Unfunded commitments | Senior Direct Lending Program                      
Schedule of Investments [Line Items]                      
Other commitment 311.0   311.0   262.0            
Ares Capital Corporation | Unfunded commitments | Senior Direct Lending Program                      
Schedule of Investments [Line Items]                      
Other commitment 73.0   73.0   62.0            
Subordinated certificates of the SDLP                      
Investments Activity And Fair Value Table [Abstract]                      
Interest income 37.0 $ 33.0 105.0 $ 106.0              
Total investments at fair value $ 1,121.0   $ 1,121.0   $ 987.0            
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%
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%      
Non-controlled affiliate                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     $ 19.9   $ 97.5            
Redemptions (cost)     48.9   64.5            
Sales (cost)     23.5   14.2            
Interest income     8.4   10.3            
Capital structuring service fees     0.1   0.3            
Dividend income $ 0.0 0.0 0.8 0.0 0.6            
Other income 0.0 0.0 0.3 1.0 1.0            
Net realized gains (losses): 29.0 1.0 6.3 58.0 67.5            
Net unrealized gains (losses): 30.0 6.0 61.9 13.0 (15.2)            
Total investments at fair value 357.7   357.7   373.1            
Controlled affiliate                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     1,541.6   757.1            
Redemptions (cost)     407.9   781.7            
Sales (cost)     0.0   57.9            
Interest income     134.9   192.1            
Capital structuring service fees     12.9   22.9            
Dividend income 55.0 23.0 173.0 72.0 100.5            
Other income 2.0 1.0 5.1 3.0 5.1            
Net realized gains (losses): 0.0 40.0 19.1 61.0 61.3            
Net unrealized gains (losses): (18.0) $ (29.0) (10.4) $ 56.0 61.4            
Total investments at fair value $ 3,753.5   $ 3,753.5   $ 2,580.4            
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date July 19, 2022, 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 $ 178.0   $ 178.0                
Derivative Asset, Notional Amount           $ 237          
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 7.0   $ 7.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date July 28, 2022, 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 $ 203.0   $ 203.0                
Derivative Asset, Notional Amount           $ 262          
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 13.0   $ 13.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Royal Bank of Canada, Company Settlement Date July 8, 2022                      
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   $ 2.0                
Derivative Asset, Notional Amount           $ 2          
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 0.0   $ 0.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Truist Financial Corporation, Company Settlement Date January 19, 2022                      
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
Derivative Liability, Notional Amount         $ 163.0            
Derivative Asset, Notional Amount                 $ 209    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset         $ (2.0)            
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Truist Financial Corporation, Company Settlement Date January 28, 2022, 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
Derivative Liability, Notional Amount         $ 240.0            
Derivative Asset, Notional Amount                 $ 309    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset         $ (5.0)            
Open Forward Foreign Currency Contract, Identifier [Axis]: CAD, Truist Financial Corporation, Company Settlement Date January 28, 2022, 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
Derivative Liability, Notional Amount         $ 1.0            
Derivative Asset, Notional Amount                 $ 2    
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset         $ 0.0            
Open Forward Foreign Currency Contract, Identifier [Axis]: EURO, Royal Bank of Canada, Company Settlement Date July 28, 2022                      
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 $ 148.0   $ 148.0                
Derivative Asset, Notional Amount | €             € 123        
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 11.0   $ 11.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: EURO, Truist Financial Corporation, Company Settlement Date January 28, 2022, 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
Derivative Liability, Notional Amount         $ 172.0            
Derivative Asset, Notional Amount | €                   € 153  
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset         $ (2.0)            
Open Forward Foreign Currency Contract, Identifier [Axis]: GBP, Royal Bank of Canada, Company Settlement Date July 28, 2022, 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 $ 137.0   $ 137.0                
Derivative Asset, Notional Amount | £               £ 135      
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 5.0   $ 5.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: GBP, Royal Bank of Canada, Company Settlement Date July 28, 2022, 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 $ 45.0   $ 45.0                
Derivative Asset, Notional Amount | £               £ 72      
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 4.0   $ 4.0                
Open Forward Foreign Currency Contract, Identifier [Axis]: GBP, Truist Financial Corporation, Company Settlement Date January 28, 2022, 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
Derivative Liability, Notional Amount         $ 126.0            
Derivative Asset, Notional Amount | £                     £ 95
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 July 28, 2022                      
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 $ 1.0   $ 1.0                
Derivative Asset, Notional Amount 1.0   1.0                
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset $ 0.0   $ 0.0                
Investment, Identifier [Axis]: 2U, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.87% [2]   8.87% [2]   6.50% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 54.6 [3],[4],[5]   $ 54.6 [3],[4],[5]   $ 55.0 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 54.6 [3],[4],[5]   54.6 [3],[4],[5]   55.0 [6],[7],[8]            
Investment, Identifier [Axis]: A.U.L. Corp. | Revolving and delayed draw loan commitments                      
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            
Less: unavailable commitments due to borrowing base or other covenant restrictions         0.0            
Total net adjusted unfunded revolving and delayed draw commitments         1.2            
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   0.4            
Total investments at fair value 0.4   0.4   0.4            
Investment, Identifier [Axis]: ACAS Equity Holdings Corporation, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.4 [5]   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   58.4            
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   (57.2)            
Net unrealized gains (losses):     0.0   58.4            
Total investments at fair value 0.0   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 7.6 [4],[9]   7.6 [4],[9]   111.4 [7],[10]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [4],[9]   0.0 [4],[9]   0.0 [7],[10]            
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.7   13.7   13.7            
Less: funded commitments (12.8)   (12.8)   (11.9)            
Total unfunded commitments 0.9   0.9   1.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.9   $ 0.9   $ 1.8            
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 7.81% [2]   7.81% [2]   7.50% [1] 7.81% [2] 7.81% [2] 7.81% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 9.0 [3],[4]   $ 9.0 [3],[4]   $ 9.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.7 [3],[4]   $ 8.7 [3],[4]   $ 9.5 [6],[7]            
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 10.00% [2]   10.00% [2]   5.75% [1] 10.00% [2] 10.00% [2] 10.00% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 3.9 [3],[4]   $ 3.9 [3],[4]   $ 2.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.8 [3],[4]   3.8 [3],[4]   2.3 [6],[7]            
Investment, Identifier [Axis]: ADG, LLC and RC IV GEDC Investor LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
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 125.6 [4]   125.6 [4]   115.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 106.8 [4]   106.8 [4]   103.7 [6],[7]            
Investment, Identifier [Axis]: AHR Funding Holdings, Inc. and AHR Parent Holdings, LP, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 9.9   9.9                
Investment, Identifier [Axis]: AHR Funding Holdings, Inc. and AHR Parent Holdings, LP, Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 0.1   0.1                
Investment, Identifier [Axis]: AHR Funding Holdings, Inc. and AHR Parent Holdings, LP, Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 35.5   $ 35.5                
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc. | Revolving and delayed draw loan commitments                      
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 commitments         $ 0.1            
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.35% [2]   6.35% [2]   4.50% [1] 6.35% [2] 6.35% [2] 6.35% [2] 4.50% [1] 4.50% [1] 4.50% [1]
Total first lien senior secured loans $ 1.0 [3],[4],[11]   $ 1.0 [3],[4],[11]   $ 0.9 [6],[7],[12]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9 [3],[4],[11]   0.9 [3],[4],[11]   0.9 [6],[7],[12]            
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.9   28.9                
Less: funded commitments (0.4)   (0.4)                
Total unfunded commitments 28.5   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 commitments 28.5   28.5                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 5.0   $ 5.0                
Investment, Identifier [Axis]: AI Fire Buyer, Inc. and AI Fire Parent LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.67%   8.67%     8.67% 8.67% 8.67%      
Total first lien senior secured loans [3],[4] $ 26.9   $ 26.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 26.9   $ 26.9                
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 [2] 9.17%   9.17%     9.17% 9.17% 9.17%      
Total first lien senior secured loans [3],[4] $ 0.4   $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.4   0.4                
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 [3],[4] 44.0   44.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 44.0   44.0                
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 [3],[4] 9.9   9.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 9.9   9.9                
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 [3],[4] 9.6   9.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 9.6   9.6                
Investment, Identifier [Axis]: AIM Acquisition, LLC | Revolving and delayed draw loan commitments                      
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 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)     0.1   0.1            
Sales (cost)     0.0   0.0            
Interest income     0.7   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):     (3.2)   (1.1)            
Total investments at fair value 21.6   21.6   25.0            
Investment, Identifier [Axis]: APG Intermediate Holdings Corporation and APG Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.1   0.1   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.1   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]                      
Total investments at fair value $ 8.4 [4]   $ 8.4 [4]   $ 11.5 [7]            
Investment, Identifier [Axis]: APG Intermediate Holdings Corporation and APG Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.15% [2]   8.15% [2]   6.75% [1] 8.15% [2] 8.15% [2] 8.15% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 13.3 [3],[4]   $ 13.3 [3],[4]   $ 13.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.2 [3],[4]   13.2 [3],[4]   13.5 [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 [4],[9] 7.4   7.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[9] 3.7   3.7                
Investment, Identifier [Axis]: AQ Sage Buyer, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.2   8.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.2   8.2                
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 commitments 8.2   8.2                
Investment, Identifier [Axis]: AQ Sunshine, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.0   15.0   1.8            
Less: funded commitments (1.4)   (1.4)   (0.3)            
Total unfunded commitments 13.6   13.6   1.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 13.6   $ 13.6   $ 1.5            
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 8.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 8.6            
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.20%   10.20%     10.20% 10.20% 10.20%      
Total first lien senior secured loans [3],[4] $ 19.3   $ 19.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 19.3   $ 19.3                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [2]   10.42% [2]   7.00% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 14.8 [3],[4]   $ 14.8 [3],[4]   $ 13.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.8 [3],[4]   $ 14.8 [3],[4]   $ 13.3 [6],[7]            
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [2]   10.42% [2]   7.00% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 8.5 [3],[4]   $ 8.5 [3],[4]   $ 20.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.5 [3],[4]   $ 8.5 [3],[4]   $ 20.2 [6],[7]            
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.42%   10.42%     10.42% 10.42% 10.42%      
Total first lien senior secured loans [3],[4] $ 5.6   $ 5.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 5.6   $ 5.6                
Investment, Identifier [Axis]: AQ Sunshine, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [2]   10.42% [2]   7.00% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 1.4 [3],[4],[13]   $ 1.4 [3],[4],[13]   $ 0.3 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.4 [3],[4],[13]   1.4 [3],[4],[13]   0.3 [6],[7],[14]            
Investment, Identifier [Axis]: ARES 2007-3R, Subordinated notes                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [5] 20.0   20.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [5] $ 0.1   $ 0.1                
Investment, Identifier [Axis]: ASP Dream Acquisition Co LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.38%   7.38%     7.38% 7.38% 7.38%      
Total first lien senior secured loans [3],[4] $ 0.0   $ 0.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.0   0.0                
Investment, Identifier [Axis]: ASP-r-pac Acquisition CO LLC and ASP-r-pac Holdings LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.2   6.2   6.2            
Less: funded commitments 0.0   0.0   (1.2)            
Total unfunded commitments 6.2   6.2   5.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 6.2   6.2   5.0            
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]                      
Total investments at fair value [4] $ 18.6   $ 18.6                
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 [2] 9.67%   9.67%     9.67% 9.67% 9.67%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
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]                      
Total investments at fair value [7]         $ 19.6            
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 [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7]         $ 46.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 45.8            
Investment, Identifier [Axis]: ASP-r-pac Acquisition Co LLC and ASP-r-pac Holdings LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7]         $ 1.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         1.2            
Investment, Identifier [Axis]: ATI Restoration, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 88.8   88.8   12.5            
Less: funded commitments (1.9)   (1.9)   (11.4)            
Total unfunded commitments 86.9   86.9   1.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 86.9   $ 86.9   $ 1.1            
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.79% [2]   7.79% [2]   6.00% [1] 7.79% [2] 7.79% [2] 7.79% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 33.1 [3],[4]   $ 33.1 [3],[4]   $ 33.3 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 33.1 [3],[4]   $ 33.1 [3],[4]   $ 33.3 [6]            
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.37%   8.37%     8.37% 8.37% 8.37%      
Total first lien senior secured loans [3],[4] $ 3.2   $ 3.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 3.2   $ 3.2                
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.25% [2]   10.25% [2]   6.00% [1] 10.25% [2] 10.25% [2] 10.25% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 1.1 [3],[4],[13]   $ 1.1 [3],[4],[13]   $ 8.1 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.1 [3],[4],[13]   1.1 [3],[4],[13]   $ 8.1 [6],[7],[14]            
Investment, Identifier [Axis]: ATI Restoration, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.25%       7.25% 7.25% 7.25%
Total first lien senior secured loans [6]         $ 2.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         2.5            
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.5   50.5            
Redemptions (cost)     3.0   26.4            
Sales (cost)     0.0   0.0            
Interest income     4.3   4.1            
Capital structuring service fees     0.0   1.6            
Dividend income     0.0   0.0            
Other income     0.0   0.1            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     4.0   5.0            
Total investments at fair value 67.4   67.4   63.9            
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.1   7.1   7.0            
Less: funded commitments (1.6)   (1.6)   (4.0)            
Total unfunded commitments 5.5   5.5   3.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 5.5   5.5   3.0            
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.3 [4]   $ 14.3 [4]   $ 10.4 [7]            
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.68% [2]   12.68% [2]   10.00% [1] 12.68% [2] 12.68% [2] 12.68% [2] 10.00% [1] 10.00% [1] 10.00% [1]
Total first lien senior secured loans $ 51.4 [3],[4]   $ 51.4 [3],[4]   $ 49.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 51.4 [3],[4]   $ 51.4 [3],[4]   $ 49.5 [6],[7]            
Investment, Identifier [Axis]: Absolute Dental Group LLC and Absolute Dental Equity, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 14.25% [2]   14.25% [2]   11.25% [1] 14.25% [2] 14.25% [2] 14.25% [2] 11.25% [1] 11.25% [1] 11.25% [1]
Total first lien senior secured loans $ 1.7 [3],[4]   $ 1.7 [3],[4]   $ 4.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.7 [3],[4]   1.7 [3],[4]   4.0 [6],[7]            
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1   13.7            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.1   0.1   13.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.1   0.1   13.7            
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd., A ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 6.5   $ 6.5                
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd., Class A ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 2.8            
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.69% [2]   13.69% [2]   10.50% [1] 13.69% [2] 13.69% [2] 13.69% [2] 10.50% [1] 10.50% [1] 10.50% [1]
Total first lien senior secured loans $ 46.2 [3],[4],[5]   $ 46.2 [3],[4],[5]   $ 13.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 46.2 [3],[4],[5]   $ 46.2 [3],[4],[5]   $ 13.7 [6],[7]            
Investment, Identifier [Axis]: Abzena Holdings, Inc. and Astro Group Holdings Ltd., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.01% [2]   11.01% [2]   11.50% [1] 11.01% [2] 11.01% [2] 11.01% [2] 11.50% [1] 11.50% [1] 11.50% [1]
Total first lien senior secured loans $ 13.9 [3],[4],[5]   $ 13.9 [3],[4],[5]   $ 30.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.9 [3],[4],[5]   13.9 [3],[4],[5]   30.5 [6],[7]            
Investment, Identifier [Axis]: Accommodations Plus Technologies LLC and Accommodations Plus Technologies Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1   4.1            
Less: funded commitments (4.1)   (4.1)   (4.1)            
Total unfunded commitments 0.0   0.0   0.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   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]                      
Total investments at fair value $ 5.1   $ 5.1   $ 4.0            
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 12.17% [2]   12.17% [2]   10.00% [1] 12.17% [2] 12.17% [2] 12.17% [2] 10.00% [1] 10.00% [1] 10.00% [1]
Total first lien senior secured loans $ 4.1 [3],[4]   $ 4.1 [3],[4]   $ 4.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.1 [3],[4]   $ 4.1 [3],[4]   $ 3.9 [6],[7]            
Investment, Identifier [Axis]: Acrisure, LLC and Acrisure Finance, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.00%   7.00%     7.00% 7.00% 7.00%      
Total first lien senior secured loans [4],[11] $ 0.5   $ 0.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[11] 0.5   0.5                
Investment, Identifier [Axis]: Advarra Holdings, Inc. | Revolving and delayed draw loan commitments                      
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 commitments $ 0.4   $ 0.4                
Investment, Identifier [Axis]: Advarra Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.12%   8.12%     8.12% 8.12% 8.12%      
Total first lien senior secured loans [3],[4] $ 4.1   $ 4.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 4.0   $ 4.0                
Investment, Identifier [Axis]: Aero Operating LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.57% [2]   9.57% [2]   8.00% [1] 9.57% [2] 9.57% [2] 9.57% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 36.3 [3],[4]   $ 36.3 [3],[4]   $ 36.6 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 34.1 [3],[4]   $ 34.1 [3],[4]   $ 36.6 [6]            
Investment, Identifier [Axis]: Aero Operating LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.57% [2]   9.57% [2]   8.00% [1] 9.57% [2] 9.57% [2] 9.57% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 1.2 [3],[4]   $ 1.2 [3],[4]   $ 1.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.1 [3],[4]   1.1 [3],[4]   1.2 [6],[7]            
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 45.6   45.6   9.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 45.6   45.6   9.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 45.6   $ 45.6   $ 9.0            
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6]         $ 64.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         64.0            
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.81%   8.81%     8.81% 8.81% 8.81%      
Total first lien senior secured loans [3],[4] $ 120.9   $ 120.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 118.4   $ 118.4                
Investment, Identifier [Axis]: AffiniPay Midco, LLC and AffiniPay Intermediate Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.33%   8.33%     8.33% 8.33% 8.33%      
Total first lien senior secured loans [3],[4] $ 63.5   $ 63.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 62.2   62.2                
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 55.0 [3],[4]   55.0 [3],[4]   27.5 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 54.4 [3],[4]   $ 54.4 [3],[4]   $ 27.5 [7]            
Investment, Identifier [Axis]: Aimbridge Acquisition Co., Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.06% [2]   10.06% [2]   7.60% [1] 10.06% [2] 10.06% [2] 10.06% [2] 7.60% [1] 7.60% [1] 7.60% [1]
Total first lien senior secured loans $ 22.5 [4]   $ 22.5 [4]   $ 22.5 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 21.6 [4]   21.6 [4]   21.4 [7]            
Investment, Identifier [Axis]: Alcami Corporation and ACM Holdings I, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 29.0   29.0   29.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 29.0   29.0   29.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 29.0   29.0   29.0            
Investment, Identifier [Axis]: Alcami Corporation and ACM Holdings I, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 44.9 [4]   $ 44.9 [4]   $ 19.5 [7]            
Investment, Identifier [Axis]: Alcami Corporation and ACM Holdings I, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.37% [2]   7.37% [2]   4.39% [1] 7.37% [2] 7.37% [2] 7.37% [2] 4.39% [1] 4.39% [1] 4.39% [1]
Total first lien senior secured loans $ 29.0 [4]   $ 29.0 [4]   $ 29.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 29.0 [4]   $ 29.0 [4]   $ 28.0            
Investment, Identifier [Axis]: Alcami Corporation and ACM Holdings I, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.12% [2]   11.12% [2]   8.14% [1] 11.12% [2] 11.12% [2] 11.12% [2] 8.14% [1] 8.14% [1] 8.14% [1]
Total first lien senior secured loans $ 77.5 [4]   $ 77.5 [4]   $ 77.5 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 77.5 [4]   $ 77.5 [4]   69.0 [7]            
Investment, Identifier [Axis]: Alera Group, Inc. | Revolving and delayed draw loan commitments                      
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            
Less: unavailable commitments due to borrowing base or other covenant restrictions         0.0            
Total net adjusted unfunded revolving and delayed draw commitments         $ 1.0            
Investment, Identifier [Axis]: Alera Group, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.05% [2]   9.05% [2]   6.25% [1] 9.05% [2] 9.05% [2] 9.05% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 75.8 [3],[4]   $ 75.8 [3],[4]   $ 96.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 75.0 [3],[4]   75.0 [3],[4]   $ 95.6 [6],[7]            
Investment, Identifier [Axis]: Alteon Health, LLC. First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7]         $ 2.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         2.8            
Investment, Identifier [Axis]: American Residential Services L.L.C. and Aragorn Parent Holdings LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5   4.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.5   4.5   4.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.5   $ 4.5   $ 4.5            
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 12.17% [2]   12.17% [2]   9.50% [1] 12.17% [2] 12.17% [2] 12.17% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 56.4 [3],[4]   $ 56.4 [3],[4]   $ 56.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 56.4 [3],[4]   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]                      
Total investments at fair value 5.5 [4]   5.5 [4]   3.7 [7]            
Investment, Identifier [Axis]: American Seafoods Group LLC and American Seafoods Partners LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [4]   0.2 [4]   0.2 [7]            
Investment, Identifier [Axis]: American Seafoods Group LLC and American Seafoods Partners LLC, Warrant to purchase Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 18.9            
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]                      
Total investments at fair value [4] $ 23.6   $ 23.6                
Investment, Identifier [Axis]: Amryt Pharmaceuticals, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.98%   8.98%     8.98% 8.98% 8.98%      
Total first lien senior secured loans [3],[4],[5] $ 12.7   $ 12.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 12.7   $ 12.7                
Investment, Identifier [Axis]: Amynta Agency Borrower Inc. and Amynta Warranty Borrower Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.62% [2]   7.62% [2]   4.60% [1] 7.62% [2] 7.62% [2] 7.62% [2] 4.60% [1] 4.60% [1] 4.60% [1]
Total first lien senior secured loans $ 2.3 [4]   $ 2.3 [4]   $ 1.0 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.2 [4]   2.2 [4]   1.0 [7]            
Investment, Identifier [Axis]: Anaplan, Inc. | Revolving and delayed draw loan commitments                      
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 commitments $ 1.4   $ 1.4                
Investment, Identifier [Axis]: Anaplan, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.53%   9.53%     9.53% 9.53% 9.53%      
Total first lien senior secured loans [3],[4] $ 21.8   $ 21.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 21.4   21.4                
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.4   3.4   4.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.4   3.4   4.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.4   $ 3.4   $ 4.3            
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans         $ 4.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 4.7            
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 [2] 5.60%   5.60%     5.60% 5.60% 5.60%      
Total first lien senior secured loans [4] $ 4.0   $ 4.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 4.0   $ 4.0                
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 8.81% [2]   8.81% [2]   7.00% [1] 8.81% [2] 8.81% [2] 8.81% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [3],[4]   $ 16.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.0 [3],[4]   1.0 [3],[4]   16.0 [6],[7]            
Investment, Identifier [Axis]: Anaqua Parent Holdings, Inc. & Astorg VII Co-Invest Anaqua, Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.1 [4],[5]   7.1 [4],[5]   7.6 [7],[8]            
Investment, Identifier [Axis]: Apex Clean Energy TopCo, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     9.1   80.5            
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):     46.7   (1.4)            
Total investments at fair value 134.9   134.9   79.1            
Investment, Identifier [Axis]: Apex Clean Energy TopCo, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 134.9   134.9   79.1            
Investment, Identifier [Axis]: Applied Technical Services, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.8   3.8                
Less: funded commitments (0.7)   (0.7)                
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 commitments $ 3.1   $ 3.1                
Investment, Identifier [Axis]: Applied Technical Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.42%   9.42%     9.42% 9.42% 9.42%      
Total first lien senior secured loans [3],[4] $ 0.8   $ 0.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.8   $ 0.8                
Investment, Identifier [Axis]: Applied Technical Services, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.00%   11.00%     11.00% 11.00% 11.00%      
Total first lien senior secured loans [3] $ 0.7   $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 0.7   0.7                
Investment, Identifier [Axis]: Appriss Health, LLC and Appriss Health Intermediate Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.1   0.1   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.1   $ 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 9.93% [2]   9.93% [2]   8.25% [1] 9.93% [2] 9.93% [2] 9.93% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 5.7 [3],[4]   $ 5.7 [3],[4]   $ 13.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 5.7 [3],[4]   5.7 [3],[4]   13.4 [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]                      
Total investments at fair value 37.6 [4]   37.6 [4]   34.6 [7]            
Investment, Identifier [Axis]: Apptio, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.2   4.2   4.2            
Less: funded commitments (1.7)   (1.7)   (1.7)            
Total unfunded commitments 2.5   2.5   2.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.5   $ 2.5   $ 2.5            
Investment, Identifier [Axis]: Apptio, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.46% [2]   8.46% [2]   8.25% [1] 8.46% [2] 8.46% [2] 8.46% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 42.2 [3],[4]   $ 42.2 [3],[4]   $ 62.2 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 41.8 [3],[4]   $ 41.8 [3],[4]   $ 62.2 [6]            
Investment, Identifier [Axis]: Apptio, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.46% [2]   8.46% [2]   8.25% [1] 8.46% [2] 8.46% [2] 8.46% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 1.7 [3],[4]   $ 1.7 [3],[4]   $ 1.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.7 [3],[4]   1.7 [3],[4]   $ 1.7 [6],[7]            
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 61.3   61.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 61.3   61.3                
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 commitments $ 61.3   $ 61.3                
Investment, Identifier [Axis]: Ardonagh Midco 2 plc and Ardonagh Midco 3 plc, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.81% [2]   8.81% [2]   8.21% [1] 8.81% [2] 8.81% [2] 8.81% [2] 8.21% [1] 8.21% [1] 8.21% [1]
Total first lien senior secured loans $ 90.0 [3],[4],[5]   $ 90.0 [3],[4],[5]   $ 69.5 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 89.1 [3],[4],[5]   $ 89.1 [3],[4],[5]   $ 69.5 [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 8.46% [2]   8.46% [2]   7.50% [1] 8.46% [2] 8.46% [2] 8.46% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 69.4 [3],[4],[5]   $ 69.4 [3],[4],[5]   $ 14.5 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 69.4 [3],[4],[5]   $ 69.4 [3],[4],[5]   $ 14.5 [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 [1]         7.75%       7.75% 7.75% 7.75%
Total first lien senior secured loans [6],[7],[8]         $ 7.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 7.5            
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 8.00% [2]   8.00% [2]   6.75% [1] 8.00% [2] 8.00% [2] 8.00% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 6.4 [3],[4],[5]   $ 6.4 [3],[4],[5]   $ 111.2 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.4 [3],[4],[5]   6.4 [3],[4],[5]   111.2 [6],[7],[8]            
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 [4],[5],[13]   1.3 [7],[8],[12]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.4 [4],[5],[13]   1.4 [4],[5],[13]   1.4 [7],[8],[12]            
Investment, Identifier [Axis]: Ares IIIR/IVR CLO Ltd., Subordinated notes                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [8]         20.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [8]         0.0            
Investment, Identifier [Axis]: Argenbright Holdings V, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         1.3            
Less: funded commitments         0.0            
Total unfunded commitments         1.3            
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 commitments         $ 1.3            
Investment, Identifier [Axis]: Argenbright Holdings V, LLC and Amberstone Security Group Limited | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.7   3.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.7   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 commitments $ 3.7   $ 3.7                
Investment, Identifier [Axis]: Argenbright Holdings V, LLC and Amberstone Security Group Limited, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.98%   9.98%     9.98% 9.98% 9.98%      
Total first lien senior secured loans [3],[4],[5] $ 21.0   $ 21.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 21.0   $ 21.0                
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 [2] 9.98%   9.98%     9.98% 9.98% 9.98%      
Total first lien senior secured loans [3],[4],[5] $ 4.4   $ 4.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 4.4   4.4                
Investment, Identifier [Axis]: Argenbright Holdings V, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 21.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         20.9            
Investment, Identifier [Axis]: Arrowhead Holdco Company and Arrowhead GS Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 20.0   20.0   20.0            
Less: funded commitments (15.0)   (15.0)   (5.0)            
Total unfunded commitments 5.0   5.0   15.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 5.0   5.0   15.0            
Investment, Identifier [Axis]: Arrowhead Holdco Company and Arrowhead GS Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 7.0 [4]   $ 7.0 [4]   $ 6.7 [7]            
Investment, Identifier [Axis]: Arrowhead Holdco Company and Arrowhead GS Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.29% [2]   7.29% [2]   5.25% [1] 7.29% [2] 7.29% [2] 7.29% [2] 5.25% [1] 5.25% [1] 5.25% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 27.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 27.2 [6],[7]            
Investment, Identifier [Axis]: Arrowhead Holdco Company and Arrowhead GS Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.62% [2]   7.62% [2]   5.25% [1] 7.62% [2] 7.62% [2] 7.62% [2] 5.25% [1] 5.25% [1] 5.25% [1]
Total first lien senior secured loans $ 13.7 [3],[4],[13]   $ 13.7 [3],[4],[13]   $ 3.7 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.4 [3],[4],[13]   13.4 [3],[4],[13]   3.6 [6],[7],[14]            
Investment, Identifier [Axis]: AthenaHealth Group Inc., Minerva Holdco, Inc. and BCPE Co-Invest (A), LP | Revolving and delayed draw loan commitments                      
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 commitments 9.0   9.0                
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]                      
Total investments at fair value [4] 10.2   10.2                
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]                      
Total investments at fair value [4] 197.4   197.4                
Investment, Identifier [Axis]: AthenaHealth Group Inc., VVC Holding Corp, Virence Intermediate Holding Corp, and Virence Holdings LLC, Class A interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         49.3            
Investment, Identifier [Axis]: Athenahealth, Inc., VVC Holding Corp., Virence Intermediate Holding Corp., and Virence Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         33.1            
Less: funded commitments         0.0            
Total unfunded commitments         33.1            
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 commitments         33.1            
Investment, Identifier [Axis]: Athyrium Buffalo LP | Private equity commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.5   15.5                
Less: funded commitments (7.6)   (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 commitments 0.0   0.0                
Investment, Identifier [Axis]: Athyrium Buffalo LP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 7.7   7.7                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.4   0.4   0.4            
Less: funded commitments (0.1)   (0.1)   0.0            
Total unfunded commitments 0.3   0.3   0.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.3   $ 0.3   $ 0.4            
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.57% [2]   8.57% [2]   6.50% [1] 8.57% [2] 8.57% [2] 8.57% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.2 [6],[7]            
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.57% [2]   8.57% [2]   6.50% [1] 8.57% [2] 8.57% [2] 8.57% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 2.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   2.1 [6],[7]            
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.57%   8.57%     8.57% 8.57% 8.57%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.2   $ 0.2                
Investment, Identifier [Axis]: Atlas Intermediate III, L.L.C., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.49%   8.49%     8.49% 8.49% 8.49%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0   $ 0.6 [7]            
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.67% [2]   8.67% [2]   6.00% [1] 8.67% [2] 8.67% [2] 8.67% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 10.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   10.0 [6],[7]            
Investment, Identifier [Axis]: Automotive Keys Group, LLC and Automotive Keys Investor, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.2 [4]   3.2 [4]   $ 4.5            
Investment, Identifier [Axis]: Aventine Intermediate LLC & Aventine Holdings II LLC | Revolving and delayed draw loan commitments                      
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 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 | Rate 9.04% [2]   9.04% [2]   6.75% [1] 9.04% [2] 9.04% [2] 9.04% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 9.3 [3],[4]   $ 9.3 [3],[4]   $ 6.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.2 [3],[4]   9.2 [3],[4]   $ 6.5 [6],[7]            
Investment, Identifier [Axis]: Aventine Intermediate LLC & Aventine Holdings II LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.25%       10.25% 10.25% 10.25%
Total first lien senior secured loans 37.5 [4]   37.5 [4]   $ 35.6 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 36.4 [4]   $ 36.4 [4]   35.3 [7]            
Investment, Identifier [Axis]: Aventine Intermediate LLC and Aventine Holdings II LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         2.6            
Less: funded commitments         0.0            
Total unfunded commitments         2.6            
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 commitments         2.6            
Investment, Identifier [Axis]: Aventiv Technologies, LLC and Securus Technologies Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.17%   8.17%     8.17% 8.17% 8.17%      
Total first lien senior secured loans [3],[4],[11] $ 9.2   $ 9.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] $ 8.0   $ 8.0                
Investment, Identifier [Axis]: Aventiv Technologies, LLC and Securus Technologies Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.06%   11.06%     11.06% 11.06% 11.06%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
Investment, Identifier [Axis]: Avetta, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.2   4.2   4.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.2   4.2   4.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.2   $ 4.2   $ 4.2            
Investment, Identifier [Axis]: Avetta, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.56% [2]   8.56% [2]   7.25% [1] 8.56% [2] 8.56% [2] 8.56% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 11.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   11.8 [6],[7]            
Investment, Identifier [Axis]: AxiomSL Group, Inc. and Calypso Group, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9   3.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.9   3.9   3.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.9   $ 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 [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 21.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         21.2            
Investment, Identifier [Axis]: AxiomSL Group, Inc. and Calypso Group, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.12%   9.12%     9.12% 9.12% 9.12%      
Total first lien senior secured loans [3],[4] $ 21.2   $ 21.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 21.2   21.2                
Investment, Identifier [Axis]: Axiomatic, LLC, Class A-1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 5.0   5.0                
Investment, Identifier [Axis]: BAART Programs, Inc., MedMark Services, Inc., and Canadian Addiction Treatment Centres LP | Revolving and delayed draw loan commitments                      
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 commitments $ 2.2   $ 2.2                
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 [2] 7.83%   7.83%     7.83% 7.83% 7.83%      
Total first lien senior secured loans [3],[4] $ 6.0   $ 6.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 6.0   6.0                
Investment, Identifier [Axis]: BCC Blueprint Holdings I, LLC and BCC Blueprint Investments, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.8 [4]   $ 3.8 [4]   $ 4.1 [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 9.54% [2]   9.54% [2]   7.00% [1] 9.54% [2] 9.54% [2] 9.54% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 0.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [3],[4]   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 4.9 [4]   4.9 [4]   4.5 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.9 [4]   4.9 [4]   4.5 [7]            
Investment, Identifier [Axis]: BH-Sharp Holdings LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 1.2   $ 1.2                
Investment, Identifier [Axis]: BW Landco LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         0.0            
Redemptions (cost)         0.0            
Sales (cost)         20.9            
Interest income         0.0            
Capital structuring service fees         0.0            
Dividend income         0.0            
Other income         0.0            
Net realized gains (losses):         20.8            
Net unrealized gains (losses):         (16.0)            
Total investments at fair value         $ 0.0            
Investment, Identifier [Axis]: Badger Sportswear Acquisition, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.12% [2]   12.12% [2]   10.25% [1] 12.12% [2] 12.12% [2] 12.12% [2] 10.25% [1] 10.25% [1] 10.25% [1]
Total first lien senior secured loans $ 56.8 [3],[4]   $ 56.8 [3],[4]   $ 56.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 56.8 [3],[4]   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]                      
Total investments at fair value $ 8.0 [4]   $ 8.0 [4]   $ 5.5 [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 10.07% [2]   10.07% [2]   7.50% [1] 10.07% [2] 10.07% [2] 10.07% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 29.5 [3],[4]   $ 29.5 [3],[4]   $ 29.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 28.9 [3],[4]   28.9 [3],[4]   29.4 [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]                      
Total investments at fair value 23.2 [4]   23.2 [4]   22.7 [7]            
Investment, Identifier [Axis]: Bambino Group Holdings, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.2 [4]   $ 1.2 [4]   1.1 [7]            
Investment, Identifier [Axis]: Bamboo Purchaser, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         4.1            
Less: funded commitments         0.0            
Total unfunded commitments         4.1            
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 commitments         $ 4.1            
Investment, Identifier [Axis]: Bamboo Purchaser, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.50% [2]   9.50% [2]   6.75% [1] 9.50% [2] 9.50% [2] 9.50% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 42.9 [3],[4]   $ 42.9 [3],[4]   $ 39.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 42.5 [3],[4]   42.5 [3],[4]   38.6 [6],[7]            
Investment, Identifier [Axis]: Banyan Software Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         33.8            
Less: funded commitments         0.0            
Total unfunded commitments         33.8            
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 commitments         $ 33.8            
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.3   19.3                
Less: funded commitments (0.9)   (0.9)                
Total unfunded commitments 18.4   18.4                
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 commitments $ 18.4   $ 18.4                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.75%       7.75% 7.75% 7.75%
Total first lien senior secured loans [6],[7]         $ 6.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 6.7            
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.17%   10.17%     10.17% 10.17% 10.17%      
Total first lien senior secured loans [3],[4] $ 9.1   $ 9.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 9.1   $ 9.1                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.17% [2]   10.17% [2]   7.75% [1] 10.17% [2] 10.17% [2] 10.17% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [3],[4]   $ 7.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.0 [3],[4]   $ 1.0 [3],[4]   $ 7.7 [6],[7]            
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7]         $ 5.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         5.0            
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.17%   10.17%     10.17% 10.17% 10.17%      
Total first lien senior secured loans [3],[4] $ 0.9   $ 0.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.9   0.9                
Investment, Identifier [Axis]: Banyan Software Holdings, LLC and Banyan Software, LP, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 5.1   5.1                
Investment, Identifier [Axis]: Beacon Pointe Harmony, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.8   6.8   9.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 6.8   6.8   9.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 6.8   $ 6.8   $ 9.0            
Investment, Identifier [Axis]: Beacon Pointe Harmony, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.37% [2]   8.37% [2]   6.00% [1] 8.37% [2] 8.37% [2] 8.37% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 16.6 [3],[4],[5]   $ 16.6 [3],[4],[5]   $ 14.5 [6],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 16.4 [3],[4],[5]   16.4 [3],[4],[5]   14.4 [6],[8]            
Investment, Identifier [Axis]: Bearcat Buyer, Inc. and Bearcat Parent, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         32.8            
Less: funded commitments         0.0            
Total unfunded commitments         32.8            
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 commitments         32.8            
Investment, Identifier [Axis]: Bearcat Buyer, Inc. and Bearcat Parent, Inc., Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 10.8            
Investment, Identifier [Axis]: Bearcat Buyer, Inc. and Bearcat Parent, Inc., Second lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.25%       9.25% 9.25% 9.25%
Total first lien senior secured loans [6],[7]         $ 69.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 69.5            
Investment, Identifier [Axis]: Bearcat Buyer, Inc. and Bearcat Parent, Inc., Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.25%       9.25% 9.25% 9.25%
Total first lien senior secured loans [6],[7]         $ 12.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         12.7            
Investment, Identifier [Axis]: Belfor Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 25.0   25.0   25.0            
Less: funded commitments (11.1)   (11.1)   (4.0)            
Total unfunded commitments 13.9   13.9   21.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 13.9   $ 13.9   $ 21.0            
Investment, Identifier [Axis]: Belfor Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 4.44% [2]   4.44% [2]   5.50% [1] 4.44% [2] 4.44% [2] 4.44% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 4.3 [4],[13]   $ 4.3 [4],[13]   $ 0.0 [7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.3 [4],[13]   $ 4.3 [4],[13]   0.0 [7],[14]            
Investment, Identifier [Axis]: Belfor Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.00%   9.00%     9.00% 9.00% 9.00%      
Total first lien senior secured loans [4],[13] $ 2.8   $ 2.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[13] 2.8   2.8                
Investment, Identifier [Axis]: Benecon Midco II LLC and Locutus Holdco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5   4.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.5   4.5   4.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 4.5   4.5   4.5            
Investment, Identifier [Axis]: Benecon Midco II LLC and Locutus Holdco LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 19.7   19.7   15.5            
Investment, Identifier [Axis]: Benefytt Technologies, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9   5.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.9   0.9   5.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.9   $ 0.9   $ 5.9            
Investment, Identifier [Axis]: Benefytt Technologies, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.09% [2]   12.09% [2]   6.75% [1] 12.09% [2] 12.09% [2] 12.09% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 23.8 [3],[4]   $ 23.8 [3],[4]   $ 23.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 19.5 [3],[4]   $ 19.5 [3],[4]   23.2 [6],[7]            
Investment, Identifier [Axis]: Benefytt Technologies, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.58%   10.58%     10.58% 10.58% 10.58%      
Total first lien senior secured loans [3],[4] $ 5.0   $ 5.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 4.1   4.1                
Investment, Identifier [Axis]: Berner Food & Beverage, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.7   1.7   1.7            
Less: funded commitments (0.9)   (0.9)   (0.7)            
Total unfunded commitments 0.8   0.8   1.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.8   $ 0.8   $ 1.0            
Investment, Identifier [Axis]: Berner Food & Beverage, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.75% [2]   10.75% [2]   8.75% [1] 10.75% [2] 10.75% [2] 10.75% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.9 [3],[4]   $ 0.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9 [3],[4]   0.9 [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 [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7]         $ 0.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.3            
Investment, Identifier [Axis]: Birch Permian, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.50%       9.50% 9.50% 9.50%
Total first lien senior secured loans [6],[7]         $ 75.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         75.7            
Investment, Identifier [Axis]: Blue Angel Buyer 1, LLC and Blue Angel Holdco, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         0.0            
Redemptions (cost)         0.0            
Sales (cost)         9.7            
Interest income         0.0            
Capital structuring service fees         0.0            
Dividend income         0.0            
Other income         0.0            
Net realized gains (losses):         46.3            
Net unrealized gains (losses):         (18.4)            
Total investments at fair value         0.0            
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   0.5            
Net unrealized gains (losses):     (0.2)   0.0            
Total investments at fair value 0.1   0.1   0.2            
Investment, Identifier [Axis]: Blue Wolf Capital Fund II, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [5],[11]   0.1 [5],[11]   0.2 [8],[12]            
Investment, Identifier [Axis]: BlueHalo Financing Holdings, LLC, BlueHalo Global Holdings, LLC, and BlueHalo, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.0   3.0                
Less: funded commitments (1.7)   (1.7)                
Total unfunded commitments 1.3   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 commitments $ 1.3   $ 1.3                
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 [2] 8.34%   8.34%     8.34% 8.34% 8.34%      
Total first lien senior secured loans [3],[4] $ 1.0   $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.0   $ 1.0                
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 [2] 8.55%   8.55%     8.55% 8.55% 8.55%      
Total first lien senior secured loans [3],[4] $ 1.7   $ 1.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.6   1.6                
Investment, Identifier [Axis]: Borrower R365 Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.9   2.9   1.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.9   2.9   1.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.9   $ 2.9   $ 1.5            
Investment, Identifier [Axis]: Borrower R365 Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7]         $ 15.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         15.5            
Investment, Identifier [Axis]: Borrower R365 Holdings LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.68%   9.68%     9.68% 9.68% 9.68%      
Total first lien senior secured loans [3],[4] $ 15.9   $ 15.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 15.9   $ 15.9                
Investment, Identifier [Axis]: Borrower R365 Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.68%   9.68%     9.68% 9.68% 9.68%      
Total first lien senior secured loans [3],[4] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.4   1.4                
Investment, Identifier [Axis]: Bottomline Technologies, Inc. | Revolving and delayed draw loan commitments                      
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 commitments $ 2.3   $ 2.3                
Investment, Identifier [Axis]: Bottomline Technologies, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.35%   8.35%     8.35% 8.35% 8.35%      
Total first lien senior secured loans [3],[4] $ 33.0   $ 33.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 32.4   32.4                
Investment, Identifier [Axis]: Bowhunter Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   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)     3.3   4.6            
Redemptions (cost)     3.0   7.8            
Sales (cost)     0.0   0.0            
Interest income     2.4   3.1            
Capital structuring service fees     0.0   0.0            
Dividend income     0.0   0.2            
Other income     0.2   0.1            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     2.4   (4.4)            
Total investments at fair value 50.4   50.4   47.8            
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.4   4.4   4.4            
Less: funded commitments (2.3)   (2.3)   (1.7)            
Total unfunded commitments 2.1   2.1   2.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.1   2.1   2.7            
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P., Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 9.9 [4]   $ 9.9 [4]   $ 8.8 [7]            
Investment, Identifier [Axis]: Bragg Live Food Products, LLC and SPC Investment Co., L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.67% [2]   10.67% [2]   7.25% [1] 10.67% [2] 10.67% [2] 10.67% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 38.9 [3],[4]   $ 38.9 [3],[4]   $ 39.4 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 38.2 [3],[4]   $ 38.2 [3],[4]   $ 37.4 [6]            
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 9.74% [2]   9.74% [2]   7.25% [1] 9.74% [2] 9.74% [2] 9.74% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 2.3 [3],[4]   $ 2.3 [3],[4]   $ 1.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.3 [3],[4]   $ 2.3 [3],[4]   1.6 [6],[7]            
Investment, Identifier [Axis]: Burgess Point Purchaser Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.41%   8.41%     8.41% 8.41% 8.41%      
Total first lien senior secured loans [3],[4],[11] $ 4.8   $ 4.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] 4.4   4.4                
Investment, Identifier [Axis]: Businessolver.com, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9   18.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.9   3.9   18.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.9   $ 3.9   $ 18.9            
Investment, Identifier [Axis]: Businessolver.com, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.50% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 14.4 [3],[4]   $ 14.4 [3],[4]   $ 70.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 14.2 [3],[4]   14.2 [3],[4]   69.5 [6],[7]            
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.0   12.0   12.0            
Less: funded commitments (3.7)   (3.7)   (3.0)            
Total unfunded commitments 8.3   8.3   9.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 8.3   $ 8.3   $ 9.0            
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   5.63% [1] 8.62% [2] 8.62% [2] 8.62% [2] 5.63% [1] 5.63% [1] 5.63% [1]
Total first lien senior secured loans $ 33.7 [4],[11]   $ 33.7 [4],[11]   $ 34.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 31.1 [4],[11]   31.1 [4],[11]   $ 33.3            
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: CDI Holdings III Corp. and CDI Holdings I Corp. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9   0.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.9   0.9   0.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.9   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]                      
Total investments at fair value $ 4.6 [4]   $ 4.6 [4]   $ 6.1 [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 9.42% [2]   9.42% [2]   6.75% [1] 9.42% [2] 9.42% [2] 9.42% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 3.8 [3],[4]   $ 3.8 [3],[4]   $ 3.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.7 [3],[4]   3.7 [3],[4]   3.8 [6],[7]            
Investment, Identifier [Axis]: CHG PPC Parent LLC & PPC CHG Blocker LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.9 [4]   $ 2.9 [4]   $ 3.0 [7]            
Investment, Identifier [Axis]: CHG PPC Parent LLC & PPC CHG Blocker LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.87% [2]   9.87% [2]   7.25% [1] 9.87% [2] 9.87% [2] 9.87% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 94.6 [3],[4]   $ 94.6 [3],[4]   $ 94.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 89.9 [3],[4]   89.9 [3],[4]   93.7 [6],[7]            
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.2   11.2                
Less: funded commitments (0.9)   (0.9)                
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 commitments 10.3   10.3                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 2.9   $ 2.9                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.02%   8.02%     8.02% 8.02% 8.02%      
Total first lien senior secured loans [3],[4] $ 24.6   $ 24.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 24.1   $ 24.1                
Investment, Identifier [Axis]: CMG HoldCo, LLC and CMG Buyer Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.31%   8.31%     8.31% 8.31% 8.31%      
Total first lien senior secured loans $ 0.9   $ 0.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9   0.9                
Investment, Identifier [Axis]: CMW Parent LLC (fka Black Arrow, Inc.), Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
Investment, Identifier [Axis]: CREST Exeter Street Solar 2004-1, Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [5]   0.0 [5]   0.0 [8]            
Investment, Identifier [Axis]: CST Buyer Company (d/b/a Intoxalock) | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.1   6.1   6.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 6.1   6.1   6.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 6.1   6.1   6.1            
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 30.5   30.5   19.7            
Less: funded commitments 0.0   0.0   (0.4)            
Total unfunded commitments 30.5   30.5   19.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 30.5   30.5   19.3            
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 17.8 [4]   $ 17.8 [4]   $ 15.9 [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 8.87% [2]   8.87% [2]   6.25% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 39.0 [3],[4]   $ 39.0 [3],[4]   $ 39.4 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 39.0 [3],[4]   $ 39.0 [3],[4]   $ 39.4 [6]            
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 8.86% [2]   8.86% [2]   6.75% [1] 8.86% [2] 8.86% [2] 8.86% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 26.6 [3],[4]   $ 26.6 [3],[4]   $ 49.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 26.6 [3],[4]   $ 26.6 [3],[4]   $ 49.2 [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 [2] 8.87%   8.87%     8.87% 8.87% 8.87%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: CVP Holdco, Inc. and OMERS Wildcats Investment Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [6],[7],[14]         $ 0.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   0.4 [6],[7],[14]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.3   15.3   15.1            
Less: funded commitments (12.6)   (12.6)   (11.7)            
Total unfunded commitments 2.7   2.7   3.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.7   $ 2.7   $ 3.4            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.31%   11.31%     11.31% 11.31% 11.31%      
Total first lien senior secured loans [3],[4] $ 31.2   $ 31.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 30.6   $ 30.6                
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.50%       9.50% 9.50% 9.50%
Total first lien senior secured loans [6]         $ 31.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 30.5            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.74% [2]   11.74% [2]   9.50% [1] 11.74% [2] 11.74% [2] 11.74% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 11.9 [3],[4]   $ 11.9 [3],[4]   $ 9.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 11.6 [3],[4]   $ 11.6 [3],[4]   $ 9.5 [6],[7]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.31% [2]   11.31% [2]   9.50% [1] 11.31% [2] 11.31% [2] 11.31% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 9.7 [3],[4]   $ 9.7 [3],[4]   $ 12.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 9.5 [3],[4]   $ 9.5 [3],[4]   11.6 [6],[7]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 12.18%   12.18%     12.18% 12.18% 12.18%      
Total first lien senior secured loans $ 7.8 [3],[4]   $ 7.8 [3],[4]   7.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 7.6 [3],[4]   $ 7.6 [3],[4]   $ 7.6 [6],[7]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.31% [2]   11.31% [2]   9.50% [1] 11.31% [2] 11.31% [2] 11.31% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 5.0 [3],[4]   $ 5.0 [3],[4]   $ 4.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.9 [3],[4]   $ 4.9 [3],[4]   $ 3.9 [6]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.31% [2]   11.31% [2]   9.50% [1] 11.31% [2] 11.31% [2] 11.31% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 11.6 [3],[4],[13]   $ 11.6 [3],[4],[13]   $ 7.9 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 11.4 [3],[4],[13]   $ 11.4 [3],[4],[13]   $ 7.6 [6],[7],[14]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.31% [2]   11.31% [2]   8.75% [1] 11.31% [2] 11.31% [2] 11.31% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.9 [3],[4]   $ 3.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9 [3],[4]   0.9 [3],[4]   $ 2.9 [6]            
Investment, Identifier [Axis]: Cadence Aerospace, LLC, First lien senior secured revolving loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.50%       9.50% 9.50% 9.50%
Total first lien senior secured loans [6],[7]         $ 0.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         0.7            
Investment, Identifier [Axis]: CallMiner, Inc., Warrant to purchase shares of Series 1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
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]                      
Total investments at 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 [2] 11.15%   11.15%     11.15% 11.15% 11.15%      
Total first lien senior secured loans [3],[4] $ 60.6   $ 60.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 60.6   60.6                
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.3   15.3   27.3            
Less: funded commitments (8.8)   (8.8)   (11.2)            
Total unfunded commitments 6.5   6.5   16.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 6.5   6.5   16.1            
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 19.8 [4]   $ 19.8 [4]   $ 14.4 [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 7.87% [2]   7.87% [2]   5.75% [1] 7.87% [2] 7.87% [2] 7.87% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 0.3 [3],[4]   $ 0.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.3 [3],[4]   0.3 [3],[4]   $ 0.3 [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]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7],[14]         $ 2.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0   $ 2.3 [6],[7],[14]            
Investment, Identifier [Axis]: Capstone Acquisition Holdings, Inc. and Capstone Parent Holdings, LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.87% [2]   11.87% [2]   9.75% [1] 11.87% [2] 11.87% [2] 11.87% [2] 9.75% [1] 9.75% [1] 9.75% [1]
Total first lien senior secured loans $ 68.3 [3],[4]   $ 68.3 [3],[4]   $ 68.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 68.3 [3],[4]   68.3 [3],[4]   68.3 [6],[7]            
Investment, Identifier [Axis]: Captive Resources Midco, LLC | Revolving and delayed draw loan commitments                      
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 commitments $ 1.2   $ 1.2                
Investment, Identifier [Axis]: Captive Resources Midco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.53%   8.53%     8.53% 8.53% 8.53%      
Total first lien senior secured loans [3],[4] $ 14.1   $ 14.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 13.8   13.8                
Investment, Identifier [Axis]: Cardinal Parent, Inc. and Packers Software Intermediate Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0   5.0            
Less: funded commitments (2.2)   (2.2)   (0.6)            
Total unfunded commitments 2.8   2.8   4.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.8   $ 2.8   $ 4.4            
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 9.75% [2]   9.75% [2]   6.75% [1] 9.75% [2] 9.75% [2] 9.75% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 2.2 [3],[4]   $ 2.2 [3],[4]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.1 [3],[4]   $ 2.1 [3],[4]   $ 0.6 [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 11.40% [2]   11.40% [2]   8.50% [1] 11.40% [2] 11.40% [2] 11.40% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 64.3 [3],[4]   $ 64.3 [3],[4]   $ 59.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 61.5 [3],[4]   61.5 [3],[4]   59.9 [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]                      
Total investments at fair value 27.9 [4]   27.9 [4]   28.0 [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]                      
Total investments at fair value 9.9 [4]   9.9 [4]   10.1 [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]                      
Total investments at fair value 11.8 [4]   11.8 [4]   13.4 [7]            
Investment, Identifier [Axis]: Cehntric Brands LLC and Centric Brands GP LLC, First lien senior secured loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 71.2   71.2                
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.7   8.7   8.5            
Less: funded commitments (8.7)   (8.7)   (8.3)            
Total unfunded commitments 0.0   0.0   0.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   0.0   $ 0.2            
Investment, Identifier [Axis]: Center for Autism and Related Disorders, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.65%       5.65% 5.65% 5.65%
Total first lien senior secured loans 6.8 [4],[9]   6.8 [4],[9]   $ 6.8 [7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.4 [4],[9]   3.4 [4],[9]   6.2 [7],[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 [4],[9] 0.2   0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[9] 0.1   0.1                
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.6   8.6   7.9            
Less: funded commitments (7.4)   (7.4)   (2.3)            
Total unfunded commitments 1.2   1.2   5.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 1.2   1.2   $ 5.6            
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.00%       10.00% 10.00% 10.00%
Total first lien senior secured loans $ 74.2 [3],[4]   $ 74.2 [3],[4]   $ 67.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 67.3            
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.63% [2]   8.63% [2]   6.50% [1] 8.63% [2] 8.63% [2] 8.63% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 7.4 [3],[4]   $ 7.4 [3],[4]   $ 2.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.1 [3],[4]   7.1 [3],[4]   2.3 [6],[7]            
Investment, Identifier [Axis]: Centric Brands LLC and Centric Brands GP LLC, Membership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.1 [4]   6.1 [4]   11.5 [7]            
Investment, Identifier [Axis]: Chariot Buyer LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.3   12.3   12.3            
Less: funded commitments (3.5)   (3.5)   (2.8)            
Total unfunded commitments 8.8   8.8   9.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 8.8   $ 8.8   $ 9.5            
Investment, Identifier [Axis]: Chariot Buyer LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.62% [2]   6.62% [2]   5.75% [1] 6.62% [2] 6.62% [2] 6.62% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 3.5 [4]   $ 3.5 [4]   $ 0.2 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.1 [4]   $ 3.1 [4]   $ 0.2 [7]            
Investment, Identifier [Axis]: Chariot Buyer LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         3.60%       3.60% 3.60% 3.60%
Total first lien senior secured loans [7]         $ 2.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 2.5            
Investment, Identifier [Axis]: Chariot Buyer LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [2]   10.42% [2]   7.50% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 134.4 [3],[4]   $ 134.4 [3],[4]   $ 134.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 126.3 [3],[4]   $ 126.3 [3],[4]   $ 133.0 [6],[7]            
Investment, Identifier [Axis]: Cheyenne Petroleum Chompany Limited Partnership, CPC 2001 LLC and Mill Shoals LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.00%       10.00% 10.00% 10.00%
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 [2] 12.67%   12.67%     12.67% 12.67% 12.67%      
Total first lien senior secured loans $ 63.1 [3],[4]   $ 63.1 [3],[4]   $ 63.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 63.1 [3],[4]   $ 63.1 [3],[4]   $ 63.1 [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 14.43% [2]   14.43% [2]   11.75% [1] 14.43% [2] 14.43% [2] 14.43% [2] 11.75% [1] 11.75% [1] 11.75% [1]
Total first lien senior secured loans $ 68.2 [3],[4]   $ 68.2 [3],[4]   $ 68.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 65.5 [3],[4]   $ 65.5 [3],[4]   $ 61.4 [6],[7]            
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 14.43% [2]   14.43% [2]   11.75% [1] 14.43% [2] 14.43% [2] 14.43% [2] 11.75% [1] 11.75% [1] 11.75% [1]
Total first lien senior secured loans $ 30.0 [3],[4]   $ 30.0 [3],[4]   $ 15.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 28.8 [3],[4]   $ 28.8 [3],[4]   13.6 [6],[7]            
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] 14.43%   14.43%     14.43% 14.43% 14.43%      
Total first lien senior secured loans $ 20.0 [3],[4]   $ 20.0 [3],[4]   15.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 19.2 [3],[4]   $ 19.2 [3],[4]   $ 13.9 [6],[7]            
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 14.43% [2]   14.43% [2]   11.75% [1] 14.43% [2] 14.43% [2] 14.43% [2] 11.75% [1] 11.75% [1] 11.75% [1]
Total first lien senior secured loans $ 15.5 [3],[4]   $ 15.5 [3],[4]   $ 20.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.8 [3],[4]   $ 14.8 [3],[4]   $ 18.0 [6],[7]            
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 14.43% [2]   14.43% [2]   11.75% [1] 14.43% [2] 14.43% [2] 14.43% [2] 11.75% [1] 11.75% [1] 11.75% [1]
Total first lien senior secured loans $ 15.2 [3],[4]   $ 15.2 [3],[4]   $ 3.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.6 [3],[4]   $ 14.6 [3],[4]   $ 2.7 [6],[7]            
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 14.43% [2]   14.43% [2]   11.75% [1] 14.43% [2] 14.43% [2] 14.43% [2] 11.75% [1] 11.75% [1] 11.75% [1]
Total first lien senior secured loans $ 4.9 [3],[4]   $ 4.9 [3],[4]   $ 4.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.7 [3],[4]   $ 4.7 [3],[4]   4.4 [6],[7]            
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] 14.43%   14.43%     14.43% 14.43% 14.43%      
Total first lien senior secured loans $ 3.0 [3],[4]   $ 3.0 [3],[4]   30.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.9 [3],[4]   2.9 [3],[4]   27.0 [6],[7]            
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., Warrant                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         3.4            
Investment, Identifier [Axis]: Cipriani USA, Inc. and Cipriani Group Holding S.A.R.L., Warrant to purchase up to 718.66 shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 6.9   6.9                
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            
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: CoLTs 2005-1 Ltd., Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [5]   0.0 [5]   0.0 [8]            
Investment, Identifier [Axis]: CoLTs 2005-2 Ltd.                      
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):         0.2            
Net unrealized gains (losses):         0.0            
Total investments at fair value         0.0            
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc. | Revolving and delayed draw loan commitments                      
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 commitments 5.3   5.3                
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         23.7            
Less: funded commitments         (0.6)            
Total unfunded commitments         23.1            
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 commitments         23.1            
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]                      
Total investments at fair value $ 3.5 [4]   $ 3.5 [4]   $ 2.8 [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 8.37% [2]   8.37% [2]   6.00% [1] 8.37% [2] 8.37% [2] 8.37% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 15.8 [3]   $ 15.8 [3]   $ 29.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 15.3 [3]   $ 15.3 [3]   $ 28.8 [6],[7]            
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.37%   8.37%     8.37% 8.37% 8.37%      
Total first lien senior secured loans [3],[4] $ 14.5   $ 14.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 14.1   $ 14.1                
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 8.37% [2]   8.37% [2]   6.00% [1] 8.37% [2] 8.37% [2] 8.37% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 2.5 [3],[4]   $ 2.5 [3],[4]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.4 [3],[4]   2.4 [3],[4]   0.6 [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]                      
Total investments at fair value 0.3 [4]   0.3 [4]   $ 0.3 [7]            
Investment, Identifier [Axis]: Cobalt Buyer Sub, Inc., Cobalt Holdings I, LP, and Cobalt Intermediate I, Inc., Series A preferred shares                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.75%       10.75% 10.75% 10.75%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 67.3 [4]   67.3 [4]   $ 60.2 [6],[7]            
Investment, Identifier [Axis]: Commercial Trailer Leasing, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   0.6   3.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.6   0.6   3.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.6   $ 0.6   $ 3.3            
Investment, Identifier [Axis]: Commercial Trailer Leasing, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.90% [2]   8.90% [2]   7.25% [1] 8.90% [2] 8.90% [2] 8.90% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 66.0 [3],[4]   $ 66.0 [3],[4]   $ 92.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 66.0 [3],[4]   $ 66.0 [3],[4]   $ 92.8 [6],[7]            
Investment, Identifier [Axis]: Commercial Trailer Leasing, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.00% [2]   13.00% [2]   13.00% [1] 13.00% [2] 13.00% [2] 13.00% [2] 13.00% [1] 13.00% [1] 13.00% [1]
Total first lien senior secured loans $ 19.9 [4]   $ 19.9 [4]   $ 19.9 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 19.7 [4]   19.7 [4]   19.9 [7]            
Investment, Identifier [Axis]: Community Brands ParentCo, LLC | Revolving and delayed draw loan commitments                      
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 commitments 7.2   7.2                
Investment, Identifier [Axis]: Community Brands ParentCo, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 7.0   $ 7.0                
Investment, Identifier [Axis]: Community Brands ParentCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.88%   8.88%     8.88% 8.88% 8.88%      
Total first lien senior secured loans [3],[4] $ 10.7   $ 10.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 10.4   10.4                
Investment, Identifier [Axis]: Compex Legal Services, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.6   3.6                
Less: funded commitments (2.0)   (2.0)                
Total unfunded commitments 1.6   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 commitments $ 1.6   $ 1.6                
Investment, Identifier [Axis]: Compex Legal Services, Inc., First lien senior secured revolving 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 [3],[4] $ 2.0   $ 2.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 2.0   2.0                
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9   1.9   1.9            
Less: funded commitments (0.3)   (0.3)   (0.3)            
Total unfunded commitments 1.6   1.6   1.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.6   $ 1.6   $ 1.6            
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.30%   9.30%     9.30% 9.30% 9.30%      
Total first lien senior secured loans [3],[4] $ 0.3   $ 0.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.3   $ 0.3                
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 2.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 2.6            
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [6],[7]         $ 0.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.1            
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 0.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.6            
Investment, Identifier [Axis]: Comprehensive EyeCare Partners, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.30% [2]   9.30% [2]   7.00% [1] 9.30% [2] 9.30% [2] 9.30% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 0.3 [3],[4]   $ 0.3 [3],[4]   $ 0.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.3 [3],[4]   0.3 [3],[4]   0.3 [6],[7]            
Investment, Identifier [Axis]: Concert Golf Partners Holdco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.1   3.1   0.6            
Less: funded commitments (0.4)   (0.4)   (0.1)            
Total unfunded commitments 2.7   2.7   0.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.7   $ 2.7   $ 0.5            
Investment, Identifier [Axis]: Concert Golf Partners Holdco LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.30% [2]   9.30% [2]   5.50% [1] 9.30% [2] 9.30% [2] 9.30% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 0.4 [3],[4]   $ 0.4 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.4 [3],[4]   $ 0.4 [3],[4]   0.1 [6],[7]            
Investment, Identifier [Axis]: Conservice Midco, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.87%   10.87%     10.87% 10.87% 10.87%      
Total first lien senior secured loans [4] $ 0.0   $ 0.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 0.0   0.0                
Investment, Identifier [Axis]: Consilio Midco Limited and Consilio Investment Holdings, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         20.0            
Less: funded commitments         0.0            
Total unfunded commitments         20.0            
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 commitments         20.0            
Investment, Identifier [Axis]: Consilio Midco Limited and Consilio Investment Holdings, L.P., Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         $ 6.0            
Investment, Identifier [Axis]: Consilio Midco Limited and Consilio Investment Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [7],[8]         $ 27.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         $ 27.5            
Investment, Identifier [Axis]: Consilio Midco Limited and Consilio Investment Holdings, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7],[8]         $ 32.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 32.6            
Investment, Identifier [Axis]: Consilio Midco Limited and Consilio Investment Holdings, L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [6],[7],[8]         $ 3.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 3.8            
Investment, Identifier [Axis]: Consilio Midco Limited and Consilio Investment Holdings, L.P., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7],[8]         $ 11.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 11.2            
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.9   13.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 13.9   13.9                
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 commitments 13.9   13.9                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 7.1   $ 7.1                
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 [2] 9.45%   9.45%     9.45% 9.45% 9.45%      
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]                      
Total first lien senior secured loans [3],[4],[5] $ 11.7   $ 11.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 11.5   $ 11.5                
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 [2] 9.42%   9.42%     9.42% 9.42% 9.42%      
Total first lien senior secured loans [3],[4],[5] $ 15.0   $ 15.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 14.7   $ 14.7                
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 [2] 7.55%   7.55%     7.55% 7.55% 7.55%      
Total first lien senior secured loans [4],[5] $ 24.7   $ 24.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 24.2   $ 24.2                
Investment, Identifier [Axis]: Consilio Midco Limited, Compusoft US LLC, and Consilio Investment Holdings, L.P., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.45%   9.45%     9.45% 9.45% 9.45%      
Total first lien senior secured loans [3],[4],[5] $ 60.0   $ 60.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 58.8   58.8                
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]                      
Total investments at fair value [4],[5] $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Continental Acquisition Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [2]   10.42% [2]   7.75% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 36.2 [3],[4]   $ 36.2 [3],[4]   $ 36.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 35.5 [3],[4]   $ 35.5 [3],[4]   $ 36.5 [6],[7]            
Investment, Identifier [Axis]: Continental Acquisition Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.42% [2]   10.42% [2]   7.75% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 5.4 [3],[4]   $ 5.4 [3],[4]   $ 33.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 5.3 [3],[4]   5.3 [3],[4]   $ 33.2 [6],[7]            
Investment, Identifier [Axis]: Continental Cafe, LLC and Infinity Ovation Yacht Charters, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [6],[7]         $ 15.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         15.5            
Investment, Identifier [Axis]: Continental Café, LLC and Infinity Ovation Yacht Charters, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.0   8.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.0   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 commitments $ 8.0   $ 8.0                
Investment, Identifier [Axis]: Continental Café, LLC and Infinity Ovation Yacht Charters, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         8.0            
Less: funded commitments         0.0            
Total unfunded commitments         8.0            
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 commitments         $ 8.0            
Investment, Identifier [Axis]: Continental Café, LLC and Infinity Ovation Yacht Charters, LLC, First lien senior secured 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 [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: Convera International Holdings Limited and Convera International Financial S.A R.L. | Revolving and delayed draw loan commitments                      
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 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 [2] 9.30%   9.30%     9.30% 9.30% 9.30%      
Total first lien senior secured loans [3],[4],[5] $ 63.0   $ 63.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 63.0   $ 63.0                
Investment, Identifier [Axis]: Convey Health Solutions, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.50%       5.50% 5.50% 5.50%
Total first lien senior secured loans [6]         $ 2.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         2.7            
Investment, Identifier [Axis]: Convey Health Solutions, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.87%   7.87%     7.87% 7.87% 7.87%      
Total first lien senior secured loans [3],[4],[5] $ 2.7   $ 2.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 2.7   $ 2.7                
Investment, Identifier [Axis]: Convey Health Solutions, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.87%   7.87%     7.87% 7.87% 7.87%      
Total first lien senior secured loans [3],[4],[5] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 0.1   0.1                
Investment, Identifier [Axis]: CoreLogic, Inc. and T-VIII Celestial Co-Invest LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 38.9   38.9   38.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 38.9   38.9   38.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 38.9   $ 38.9   38.9            
Investment, Identifier [Axis]: CoreLogic, Inc. and T-VIII Celestial Co-Invest LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.63%   6.63%     6.63% 6.63% 6.63%      
Total first lien senior secured loans [3],[4] $ 4.1   $ 4.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 3.3   3.3                
Investment, Identifier [Axis]: CoreLogic, Inc. and T-VIII Celestial Co-Invest LP, Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 62.4 [4]   $ 62.4 [4]   $ 77.9 [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 9.63% [2]   9.63% [2]   7.00% [1] 9.63% [2] 9.63% [2] 9.63% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 155.7 [3],[4]   $ 155.7 [3],[4]   $ 155.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 132.3 [3],[4]   132.3 [3],[4]   155.7 [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]                      
Total investments at fair value [4],[5] $ 0.0   $ 0.0                
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 [2] 8.81%   8.81%     8.81% 8.81% 8.81%      
Total first lien senior secured loans [3],[4],[5] $ 16.5   $ 16.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 16.5   $ 16.5                
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 [2] 7.28%   7.28%     7.28% 7.28% 7.28%      
Total first lien senior secured loans [3],[4],[5] $ 4.4   $ 4.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 4.4   $ 4.4                
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 [2] 9.28%   9.28%     9.28% 9.28% 9.28%      
Total first lien senior secured loans [3],[4],[5] $ 1.1   $ 1.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 1.1   $ 1.1                
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 [2] 7.28%   7.28%     7.28% 7.28% 7.28%      
Total first lien senior secured loans [3],[4],[5] $ 6.3   $ 6.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 6.3   6.3                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc. and Cority Parent, Inc., Preferred equity                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 0.6   0.6                
Investment, Identifier [Axis]: Cority Software Inc., Cority Software (USA) Inc., and Cority Parent, Inc. | Revolving and delayed draw loan commitments                      
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 commitments 6.2   6.2                
Investment, Identifier [Axis]: Cority Software Inc., IQS, Inc. and Cority Parent, Inc. | Revolving and delayed draw loan commitments                      
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 commitments         0.1            
Investment, Identifier [Axis]: Cority Software Inc., IQS, Inc. and Cority Parent, Inc., Common equity                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         $ 0.0            
Investment, Identifier [Axis]: Cority Software Inc., IQS, Inc. and Cority Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6],[8]         $ 6.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[8]         $ 6.3            
Investment, Identifier [Axis]: Cority Software Inc., IQS, Inc. and Cority Parent, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6],[8]         $ 4.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[8]         $ 4.4            
Investment, Identifier [Axis]: Cority Software Inc., IQS, Inc. and Cority Parent, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [6],[7],[8]         $ 1.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         1.1            
Investment, Identifier [Axis]: Cority Software Inc., IQS, Inc. and Cority Parent, Inc., Preferred equity                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         0.6            
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 38.7   38.7   38.7            
Less: funded commitments (22.7)   (22.7)   (0.1)            
Total unfunded commitments 16.0   16.0   38.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 16.0   16.0   38.6            
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., Class A-1 common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 15.1 [4]   $ 15.1 [4]   $ 13.3 [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 6.21% [2]   6.21% [2]   0.00% [1] 6.21% [2] 6.21% [2] 6.21% [2] 0.00% [1] 0.00% [1] 0.00% [1]
Total first lien senior secured loans [4],[13] $ 21.9   $ 21.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 20.2 [4],[13]   $ 20.2 [4],[13]   $ 0.0 [16]            
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.62% [2]   9.62% [2]   7.00% [1] 9.62% [2] 9.62% [2] 9.62% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 137.5 [3],[4]   $ 137.5 [3],[4]   $ 137.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 125.1 [3],[4]   125.1 [3],[4]   135.4 [6]            
Investment, Identifier [Axis]: Cornerstone OnDemand, Inc. and Sunshine Software Holdings, Inc., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 111.4 [4]   111.4 [4]   119.0 [7]            
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC | Revolving and delayed draw loan commitments                      
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 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]                      
Total investments at fair value $ 5.8   $ 5.8                
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.56%   7.56%     7.56% 7.56% 7.56%      
Total first lien senior secured loans [3],[4] $ 8.7   $ 8.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 8.7   $ 8.7                
Investment, Identifier [Axis]: Covaris Intermediate 3, LLC & Covaris Parent, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.37%   8.37%     8.37% 8.37% 8.37%      
Total first lien senior secured loans [3],[4] $ 1.5   $ 1.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.5   1.5                
Investment, Identifier [Axis]: Coyote Buyer, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.3   8.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 8.3   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 commitments $ 8.3   $ 8.3                
Investment, Identifier [Axis]: Coyote Buyer, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.81%   8.81%     8.81% 8.81% 8.81%      
Total first lien senior secured loans [3],[4] $ 0.8   $ 0.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.7   $ 0.7                
Investment, Identifier [Axis]: Coyote Buyer, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.67%   11.67%     11.67% 11.67% 11.67%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
Investment, Identifier [Axis]: Cozzini Bros., Inc. and BH-Sharp Holdings LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         15.0            
Less: funded commitments         0.0            
Total unfunded commitments         15.0            
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 commitments         15.0            
Investment, Identifier [Axis]: Cozzini Bros., Inc. and BH-Sharp Holdings LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 1.4            
Investment, Identifier [Axis]: Cozzini Bros., Inc. and BH-Sharp Holdings LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7]         $ 12.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         11.4            
Investment, Identifier [Axis]: CrossCountry Mortgage, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 56.3   56.3   56.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 56.3   56.3   56.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 56.3   $ 56.3   $ 56.3            
Investment, Identifier [Axis]: CrossCountry Mortgage, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.07% [2]   10.07% [2]   7.50% [1] 10.07% [2] 10.07% [2] 10.07% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 93.8 [3],[4]   $ 93.8 [3],[4]   $ 93.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 92.8 [3],[4]   92.8 [3],[4]   92.8 [6],[7]            
Investment, Identifier [Axis]: Crown CT Parent Inc., Crown CT HoldCo Inc. and Crown CT Management LLC | Revolving and delayed draw loan commitments                      
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 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]                      
Total investments at fair value [4] 2.0   2.0                
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]                      
Total investments at fair value [4] $ 0.3   $ 0.3                
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 [2] 8.67%   8.67%     8.67% 8.67% 8.67%      
Total first lien senior secured loans [3],[4] $ 24.6   $ 24.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 24.6   24.6                
Investment, Identifier [Axis]: Crown Health Care Laundry Services, LLC and Crown Laundry Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         0.0            
Redemptions (cost)         27.2            
Sales (cost)         4.5            
Interest income         (0.5)            
Capital structuring service fees         0.0            
Dividend income         0.0            
Other income         0.9            
Net realized gains (losses):         10.7            
Net unrealized gains (losses):         (8.0)            
Total investments at fair value         0.0            
Investment, Identifier [Axis]: DCert Preferred Holdings, Inc. and Destiny Digital Holdings, L.P., Series A preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         138.1            
Investment, Identifier [Axis]: DCert Preferred Holdings, Inc. and Destiny Digital Holdings, L.P., Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         13.4            
Investment, Identifier [Axis]: DFC Global Facility Borrower III LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 94.7   94.7   103.5            
Less: funded commitments (76.0)   (76.0)   (73.2)            
Total unfunded commitments 18.7   18.7   30.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 18.7   $ 18.7   $ 30.3            
Investment, Identifier [Axis]: DFC Global Facility Borrower III LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.06% [2]   10.06% [2]   8.50% [1] 10.06% [2] 10.06% [2] 10.06% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 152.0 [3],[4],[5],[17]   $ 152.0 [3],[4],[5],[17]   $ 146.4 [6],[7],[8],[18]            
Participating interest sold 79.3   79.3   75.0            
Secured borrowings 79.3   79.3   73.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 152.0 [3],[4],[5],[17]   $ 152.0 [3],[4],[5],[17]   $ 146.4 [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 10.06%   10.06%   8.50% 10.06% 10.06% 10.06% 8.50% 8.50% 8.50%
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.62% [2]   10.62% [2]   8.50% [1] 10.62% [2] 10.62% [2] 10.62% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 165.3 [3]   $ 165.3 [3]   $ 166.7 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 165.3 [3]   $ 165.3 [3]   $ 158.4 [6]            
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.62% [2]   10.62% [2]   8.50% [1] 10.62% [2] 10.62% [2] 10.62% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 6.5 [3],[4]   $ 6.5 [3],[4]   $ 4.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.5 [3],[4]   $ 6.5 [3],[4]   $ 4.1 [6],[7]            
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.62% [2]   10.62% [2]   8.50% [1] 10.62% [2] 10.62% [2] 10.62% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 4.3 [3],[4]   $ 4.3 [3],[4]   $ 5.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.3 [3],[4]   4.3 [3],[4]   $ 4.7 [6]            
Investment, Identifier [Axis]: DFS Holding Company, Inc., First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 0.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         0.6            
Investment, Identifier [Axis]: DRS Holdings III, Inc. and DRS Holdings I, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.8   10.8   10.8            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 10.8   10.8   10.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 10.8   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]                      
Total investments at fair value $ 8.4 [4]   $ 8.4 [4]   $ 11.3 [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 8.87% [2]   8.87% [2]   6.75% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 28.9 [3],[4]   $ 28.9 [3],[4]   $ 29.8 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 28.1 [3],[4]   $ 28.1 [3],[4]   $ 29.8 [6]            
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 8.87% [2]   8.87% [2]   6.75% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 26.7 [3],[4]   $ 26.7 [3],[4]   $ 46.7 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 25.9 [3],[4]   25.9 [3],[4]   46.7 [6]            
Investment, Identifier [Axis]: DS Admiral Bidco, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.1   0.1   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.1   $ 0.1   $ 0.1            
Investment, Identifier [Axis]: DS Admiral Bidco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.56% [2]   8.56% [2]   6.75% [1] 8.56% [2] 8.56% [2] 8.56% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 11.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   11.9 [6],[7]            
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         6.6            
Less: funded commitments         (5.2)            
Total unfunded commitments         1.4            
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 commitments         1.4            
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.5 [4]   6.5 [4]   4.2 [7]            
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc., Class B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [4]   $ 0.0 [4]   $ 0.0 [7]            
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [7],[14]         $ 0.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[14]         $ 0.3            
Investment, Identifier [Axis]: DTI Holdco, Inc. and OPE DTI Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         4.65%       4.65% 4.65% 4.65%
Total first lien senior secured loans [7],[14]         $ 4.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[14]         $ 4.8            
Investment, Identifier [Axis]: Datix Bidco Limited, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.01% [2]   6.01% [2]   4.18% [1] 6.01% [2] 6.01% [2] 6.01% [2] 4.18% [1] 4.18% [1] 4.18% [1]
Total first lien senior secured loans $ 0.1 [4],[5]   $ 0.1 [4],[5]   $ 0.1 [7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [4],[5]   $ 0.0 [4],[5]   0.1 [7],[8]            
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 [2] 9.90%   9.90%     9.90% 9.90% 9.90%      
Total first lien senior secured loans [4] $ 8.8   $ 8.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 8.5   8.5                
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]                      
Total investments at fair value [4] 132.9   132.9                
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]                      
Total investments at fair value [4] 12.4   12.4                
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 16.5   16.5   16.5            
Less: funded commitments (14.1)   (14.1)   (2.4)            
Total unfunded commitments 2.4   2.4   14.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.4   2.4   14.1            
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 9.3 [4]   $ 9.3 [4]   $ 10.0 [7]            
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.17% [2]   10.17% [2]   9.00% [1] 10.17% [2] 10.17% [2] 10.17% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 148.9 [3],[4]   $ 148.9 [3],[4]   $ 148.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 147.3 [3],[4]   $ 147.3 [3],[4]   $ 148.5 [6],[7]            
Investment, Identifier [Axis]: DecoPac, Inc. and KCAKE Holdings Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.67% [2]   9.67% [2]   7.00% [1] 9.67% [2] 9.67% [2] 9.67% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 14.1 [3],[4]   $ 14.1 [3],[4]   $ 2.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 14.0 [3],[4]   14.0 [3],[4]   $ 2.4 [6],[7]            
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.4   11.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 11.4   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 commitments 11.4   11.4                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 2.5   $ 2.5                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Apexco LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.79% [2]   8.79% [2]   7.00% [1] 8.79% [2] 8.79% [2] 8.79% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 1.2 [3],[4]   $ 1.2 [3],[4]   $ 37.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.2 [3],[4]   $ 1.2 [3],[4]   36.9 [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 [2] 8.79%   8.79%     8.79% 8.79% 8.79%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Topco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         5.4            
Less: funded commitments         0.0            
Total unfunded commitments         5.4            
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 commitments         5.4            
Investment, Identifier [Axis]: Denali Holdco LLC and Denali Topco LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         2.5            
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.2   2.2   9.7            
Less: funded commitments (1.2)   (1.2)   0.0            
Total unfunded commitments 1.0   1.0   9.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.0   $ 1.0   $ 9.7            
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.25%       7.25% 7.25% 7.25%
Total first lien senior secured loans [6]         $ 33.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 33.0            
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.13%   9.13%     9.13% 9.13% 9.13%      
Total first lien senior secured loans [3],[4] $ 36.0   $ 36.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 35.3   $ 35.3                
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.13% [2]   9.13% [2]   6.75% [1] 9.13% [2] 9.13% [2] 9.13% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 2.0 [3],[4]   $ 8.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.0 [3],[4]   $ 2.0 [3],[4]   $ 8.9 [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 8.63% [2]   8.63% [2]   6.75% [1] 8.63% [2] 8.63% [2] 8.63% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 11.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 11.4 [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 8.63% [2]   8.63% [2]   7.25% [1] 8.63% [2] 8.63% [2] 8.63% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 2.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 2.0 [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 8.49% [2]   8.49% [2]   0.00% [1] 8.49% [2] 8.49% [2] 8.49% [2] 0.00% [1] 0.00% [1] 0.00% [1]
Total first lien senior secured loans [3],[4],[13] $ 1.1   $ 1.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.1 [3],[4],[13]   1.1 [3],[4],[13]   $ 0.0 [16]            
Investment, Identifier [Axis]: Diligent Corporation and Diligent Preferred Issuer, Inc., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 14.3 [4]   14.3 [4]   13.8 [7]            
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.3   2.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.3   2.3   2.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.3   2.3   2.3            
Investment, Identifier [Axis]: Display Holding Company, Inc., Saldon Holdings, Inc. and Fastsigns Holdings Inc., Common units                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]         600.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.1 [4]   $ 1.1 [4]   $ 1.0 [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 8.77% [2]   8.77% [2]   6.65% [1] 8.77% [2] 8.77% [2] 8.77% [2] 6.65% [1] 6.65% [1] 6.65% [1]
Total first lien senior secured loans $ 15.9 [3],[4]   $ 15.9 [3],[4]   $ 16.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 15.9 [3],[4]   $ 15.9 [3],[4]   $ 16.0 [6]            
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 8.77% [2]   8.77% [2]   6.65% [1] 8.77% [2] 8.77% [2] 8.77% [2] 6.65% [1] 6.65% [1] 6.65% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 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 8.77% [2]   8.77% [2]   6.65% [1] 8.77% [2] 8.77% [2] 8.77% [2] 6.65% [1] 6.65% [1] 6.65% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   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]                      
Total investments at fair value $ 40.6 [4]   $ 40.6 [4]   $ 37.9 [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 11.37% [2]   11.37% [2]   8.35% [1] 11.37% [2] 11.37% [2] 11.37% [2] 8.35% [1] 8.35% [1] 8.35% [1]
Total first lien senior secured loans $ 25.0 [4]   $ 25.0 [4]   $ 25.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 24.5 [4]   24.5 [4]   25.0            
Investment, Identifier [Axis]: Dye & Durham Corporation | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 17.8   17.8   19.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 17.8   17.8   19.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 17.8   $ 17.8   $ 19.5            
Investment, Identifier [Axis]: Dye & Durham Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   6.50% [1] 8.62% [2] 8.62% [2] 8.62% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 39.2 [3],[4],[5]   $ 39.2 [3],[4],[5]   $ 72.0 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 39.2 [3],[4],[5]   39.2 [3],[4],[5]   70.9 [6],[7],[8]            
Investment, Identifier [Axis]: Dynamic NC Aerospace Holdings, LLC and Dynamic NC Investment Holdings, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.1   7.1   7.1            
Less: funded commitments (1.4)   (1.4)   0.0            
Total unfunded commitments 5.7   5.7   7.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 5.7   5.7   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]                      
Total investments at fair value $ 8.3   $ 8.3   $ 8.6            
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 10.17% [2]   10.17% [2]   7.50% [1] 10.17% [2] 10.17% [2] 10.17% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 25.7 [3],[4]   $ 25.7 [3],[4]   $ 25.7 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 25.4 [3],[4]   $ 25.4 [3],[4]   25.4 [6]            
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 [2] 9.06%   9.06%     9.06% 9.06% 9.06%      
Total first lien senior secured loans [3],[4] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.4   1.4                
Investment, Identifier [Axis]: EP Purchaser, LLC and TPG VIII EP Co-Invest II, L.P., Partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 11.6 [4],[5]   $ 11.6 [4],[5]   $ 9.8 [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 10.17% [2]   10.17% [2]   7.00% [1] 10.17% [2] 10.17% [2] 10.17% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 177.9 [3],[4]   $ 177.9 [3],[4]   $ 177.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 174.3 [3],[4]   174.3 [3],[4]   176.1 [6],[7]            
Investment, Identifier [Axis]: EP Wealth Advisors, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.6   1.6   2.8            
Less: funded commitments (0.7)   (0.7)   (0.2)            
Total unfunded commitments 0.9   0.9   2.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.9   $ 0.9   $ 2.6            
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.93% [2]   7.93% [2]   5.50% [1] 7.93% [2] 7.93% [2] 7.93% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 1.5 [3],[4]   $ 1.5 [3],[4]   $ 0.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.5 [3],[4]   $ 1.5 [3],[4]   $ 0.2 [6],[7]            
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.17% [2]   8.17% [2]   6.25% [1] 8.17% [2] 8.17% [2] 8.17% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 0.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 0.3 [6],[7]            
Investment, Identifier [Axis]: EP Wealth Advisors, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.17% [2]   8.17% [2]   5.50% [1] 8.17% [2] 8.17% [2] 8.17% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 0.7 [3],[4]   $ 0.7 [3],[4]   $ 0.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.7 [3],[4]   0.7 [3],[4]   0.2 [6],[7]            
Investment, Identifier [Axis]: EPS NASS Parent, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.5   6.6            
Less: funded commitments (0.6)   (0.6)   (0.9)            
Total unfunded commitments 0.9   0.9   5.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.9   $ 0.9   $ 5.7            
Investment, Identifier [Axis]: EPS NASS Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.42% [2]   9.42% [2]   6.75% [1] 9.42% [2] 9.42% [2] 9.42% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 30.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 30.5 [6],[7]            
Investment, Identifier [Axis]: EPS NASS Parent, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.40% [2]   9.40% [2]   6.75% [1] 9.40% [2] 9.40% [2] 9.40% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.6 [3],[4],[13]   $ 0.6 [3],[4],[13]   $ 0.9 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.6 [3],[4],[13]   0.6 [3],[4],[13]   0.9 [6],[7],[14]            
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     2.3   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):     (2.6)   (0.3)            
Total investments at fair value 2.4   2.4   2.8            
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         2.8            
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC, Class A-1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 2.3   2.3                
Investment, Identifier [Axis]: ESCP PPG Holdings, LLC, Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1   0.1                
Investment, Identifier [Axis]: ESHA Research, LLC and RMCF VI CIV XLVIII, L.P. | Revolving and delayed draw loan commitments                      
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 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 [2] 8.96%   8.96%     8.96% 8.96% 8.96%      
Total first lien senior secured loans [3],[4] $ 6.8   $ 6.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [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]                      
Total investments at fair value 4.8   4.8                
Investment, Identifier [Axis]: Eckler Industries, Inc. and Eckler Purchaser LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     8.2   3.5            
Redemptions (cost)     0.0   0.0            
Sales (cost)     0.0   0.0            
Interest income     0.0   2.5            
Capital structuring service fees     0.0   0.0            
Dividend income     0.0   0.0            
Other income     0.0   0.0            
Net realized gains (losses):     0.1   0.0            
Net unrealized gains (losses):     (29.1)   (8.1)            
Total investments at fair value 2.3   2.3   23.1            
Investment, Identifier [Axis]: Eckler Industries, Inc. and Eckler Purchaser LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 16.4   16.4   6.9            
Less: funded commitments (15.9)   (15.9)   (6.7)            
Total unfunded commitments 0.5   0.5   0.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   (0.2)            
Total net adjusted unfunded revolving and delayed draw commitments 0.5   0.5   0.0            
Investment, Identifier [Axis]: Eckler Industries, Inc. and Eckler Purchaser LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
Investment, Identifier [Axis]: Eckler Industries, Inc. and Eckler Purchaser LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 28.8 [4],[9]   28.8 [4],[9]   26.3 [7],[10]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.5 [4],[9]   1.5 [4],[9]   18.4 [7],[10]            
Investment, Identifier [Axis]: Eckler Industries, Inc. and Eckler Purchaser LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 15.9 [4],[9]   15.9 [4],[9]   6.7 [7],[10]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.8 [4],[9]   0.8 [4],[9]   4.7 [7],[10]            
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc, Preferred equity                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 6.0   6.0                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.1   8.1   4.1            
Less: funded commitments (4.1)   (4.1)   (2.3)            
Total unfunded commitments 4.0   4.0   1.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.0   $ 4.0   $ 1.8            
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6]         $ 62.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         61.9            
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.01%   9.01%     9.01% 9.01% 9.01%      
Total first lien senior secured loans [3],[4] $ 61.5   $ 61.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 60.3   $ 60.3                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.79%   8.79%     8.79% 8.79% 8.79%      
Total first lien senior secured loans $ 5.8 [3],[4]   $ 5.8 [3],[4]   20.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.6 [3],[4]   $ 5.6 [3],[4]   $ 20.5 [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 [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 2.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         2.3            
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured revolving loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.57%   8.57%     8.57% 8.57% 8.57%      
Total first lien senior secured loans [3],[4] $ 3.1   $ 3.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 3.0   $ 3.0                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.75%   10.75%     10.75% 10.75% 10.75%      
Total first lien senior secured loans [3] $ 1.0   $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 1.0   1.0                
Investment, Identifier [Axis]: Elemica Parent, Inc. & EZ Elemica Holdings, Inc., Preferred equity                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 5.5            
Investment, Identifier [Axis]: Elemica Parent, Inc. h& EZ Elemica Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 14.2            
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 17.4   17.4                
Less: funded commitments (1.4)   (1.4)                
Total unfunded commitments 16.0   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 commitments $ 16.0   $ 16.0                
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.43% [2]   9.43% [2]   7.00% [1] 9.43% [2] 9.43% [2] 9.43% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 8.8 [3],[4]   $ 8.8 [3],[4]   $ 8.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.8 [3],[4]   $ 8.8 [3],[4]   $ 8.7 [6],[7]            
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.84% [2]   8.84% [2]   6.50% [1] 8.84% [2] 8.84% [2] 8.84% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 10.3 [3],[4]   $ 10.3 [3],[4]   $ 0.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 10.3 [3],[4]   $ 10.3 [3],[4]   $ 0.3 [6],[7]            
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 5.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         5.2            
Investment, Identifier [Axis]: Elevation Services Parent Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.16%   9.16%     9.16% 9.16% 9.16%      
Total first lien senior secured loans [3],[4],[13] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[13] 1.4   1.4                
Investment, Identifier [Axis]: Emergency Communications Network, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.7   6.7   6.5            
Less: funded commitments (6.7)   (6.7)   0.0            
Total unfunded commitments 0.0   0.0   6.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.0   $ 0.0   $ 6.5            
Investment, Identifier [Axis]: Emergency Communications Network, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.33% [2]   10.33% [2]   8.75% [1] 10.33% [2] 10.33% [2] 10.33% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 47.8 [3],[4]   $ 47.8 [3],[4]   $ 46.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 43.0 [3],[4]   $ 43.0 [3],[4]   42.4 [6],[7]            
Investment, Identifier [Axis]: Emergency Communications Network, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.70%   10.70%     10.70% 10.70% 10.70%      
Total first lien senior secured loans [3],[4] $ 6.7   $ 6.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 6.1   $ 6.1                
Investment, Identifier [Axis]: Ensemble RCM, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.81%   7.81%     7.81% 7.81% 7.81%      
Total first lien senior secured loans [3] $ 2.5   $ 2.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 2.5   2.5                
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.5   14.5   14.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 14.5   14.5   14.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 14.5   $ 14.5   $ 14.5            
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 4.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 4.6            
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.19%   7.19%     7.19% 7.19% 7.19%      
Total first lien senior secured loans [4] $ 5.2   $ 5.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 5.1   $ 5.1                
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.42% [2]   9.42% [2]   5.75% [1] 9.42% [2] 9.42% [2] 9.42% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 6.0 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 6.0 [7]            
Investment, Identifier [Axis]: EpiServer Inc. and Episerver Sweden Holdings AB, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.42% [2]   9.42% [2]   6.50% [1] 9.42% [2] 9.42% [2] 9.42% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   0.1 [6],[7]            
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 39.4   39.4   53.3            
Less: funded commitments (6.2)   (6.2)   (1.0)            
Total unfunded commitments 33.2   33.2   52.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 33.2   33.2   52.3            
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 37.8 [4]   $ 37.8 [4]   $ 34.4 [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 [2] 8.03%   8.03%     8.03% 8.03% 8.03%      
Total first lien senior secured loans [3],[4] $ 78.3   $ 78.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 77.5   $ 77.5                
Investment, Identifier [Axis]: Essential Services Holding Corporation and OMERS Mahomes Investment Holdings LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7]         $ 72.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 72.7            
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 8.03% [2]   8.03% [2]   6.75% [1] 8.03% [2] 8.03% [2] 8.03% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 48.3 [3],[4]   $ 48.3 [3],[4]   $ 80.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 47.8 [3],[4]   $ 47.8 [3],[4]   $ 80.4 [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 [2] 8.07%   8.07%     8.07% 8.07% 8.07%      
Total first lien senior secured loans [3],[4] $ 13.8   $ 13.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 13.7   13.7                
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]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: European Capital UK SME Debt LP                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0   0.0            
Redemptions (cost)     0.8   7.7            
Sales (cost)     0.0   0.0            
Interest income     0.0   0.0            
Capital structuring service fees     0.0   0.0            
Dividend income     0.8   0.4            
Other income     0.0   0.0            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     (2.4)   4.9            
Total investments at fair value 23.7   23.7   26.9            
Investment, Identifier [Axis]: European Capital UK SME Debt LP | Private equity commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 50.3   50.3   60.9            
Less: funded commitments (45.5)   (45.5)   (55.1)            
Total unfunded commitments 4.8   4.8   5.8            
Less: commitments substantially at discretion of the Company (4.8)   (4.8)   (5.8)            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   0.0   0.0            
Investment, Identifier [Axis]: European Capital UK SME Debt LP, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 23.7 [5]   23.7 [5]   26.9 [8],[19]            
Investment, Identifier [Axis]: Everspin Technologies, Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 0.0            
Investment, Identifier [Axis]: Everspin Technologies, Inc., Warrant to purchase up to 18,461 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Evolent Health LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.20%   9.20%     9.20% 9.20% 9.20%      
Total first lien senior secured loans [3],[4],[5] $ 7.8   $ 7.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 7.7   $ 7.7                
Investment, Identifier [Axis]: Excelligence Holdings Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.67% [2]   9.67% [2]   7.00% [1] 9.67% [2] 9.67% [2] 9.67% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 9.1 [3],[4]   $ 9.1 [3],[4]   $ 9.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.1 [3],[4]   9.1 [3],[4]   $ 9.3 [6],[7]            
Investment, Identifier [Axis]: Explorer Investor, Inc | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.3   0.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.3   0.3                
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 commitments $ 0.3   $ 0.3                
Investment, Identifier [Axis]: Explorer Investor, Inc, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.03%   9.03%     9.03% 9.03% 9.03%      
Total first lien senior secured loans [3],[4] $ 1.2   $ 1.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.1   1.1                
Investment, Identifier [Axis]: ExtraHop Networks, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7]         $ 16.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 16.4            
Investment, Identifier [Axis]: ExtraHop Networks, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7]         $ 1.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         1.0            
Investment, Identifier [Axis]: Extrahop Networks, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.6   6.6   8.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 6.6   6.6   8.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 6.6   $ 6.6   8.5            
Investment, Identifier [Axis]: Extrahop Networks, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.17%   11.17%     11.17% 11.17% 11.17%      
Total first lien senior secured loans [3],[4] $ 16.6   $ 16.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 16.6   $ 16.6                
Investment, Identifier [Axis]: Extrahop Networks, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.17%   11.17%     11.17% 11.17% 11.17%      
Total first lien senior secured loans [3],[4] $ 3.0   $ 3.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 3.0   3.0                
Investment, Identifier [Axis]: FL Hawk Intermediate Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.5   0.5   0.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.5   0.5   0.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.5   0.5   0.5            
Investment, Identifier [Axis]: FM:Systems Group, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.5   1.5            
Less: funded commitments 0.0   0.0   (1.5)            
Total unfunded commitments 1.5   1.5   0.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.5   $ 1.5   $ 0.0            
Investment, Identifier [Axis]: FM:Systems Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7]         $ 3.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 3.2            
Investment, Identifier [Axis]: FM:Systems Group, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.13%   9.13%     9.13% 9.13% 9.13%      
Total first lien senior secured loans [3],[4] $ 3.2   $ 3.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 3.2   $ 3.2                
Investment, Identifier [Axis]: FM:Systems Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.05% [2]   9.05% [2]   7.50% [1] 9.05% [2] 9.05% [2] 9.05% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 1.4 [3],[4]   $ 1.4 [3],[4]   $ 1.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.4 [3],[4]   1.4 [3],[4]   $ 1.4 [6],[7]            
Investment, Identifier [Axis]: FM:Systems Group, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7]         $ 1.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         1.5            
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.6   9.6   9.6            
Less: funded commitments (0.5)   (0.5)   (0.5)            
Total unfunded commitments 9.1   9.1   9.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 9.1   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]                      
Total investments at fair value $ 28.2 [4]   $ 28.2 [4]   $ 19.2 [7]            
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.28% [2]   8.28% [2]   5.36% [1] 8.28% [2] 8.28% [2] 8.28% [2] 5.36% [1] 5.36% [1] 5.36% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   $ 0.1 [7]            
Investment, Identifier [Axis]: FS Squared Holding Corp. and FS Squared, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Faraday&Future Inc., FF Inc., Faraday SPE, LLC and Faraday Future Intelligent Electric Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]         80.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         80.3            
Investment, Identifier [Axis]: Faraday&Future Inc., FF Inc., Faraday SPE, LLC and Faraday Future Intelligent Electric Inc., Warrant to purchase shares of Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 1.2            
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]                      
Total investments at fair value [4] 0.2   0.2                
Investment, Identifier [Axis]: Ferrellgas, L.P. and Ferrellgas Partners L.P., Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.9   $ 14.9                
Investment, Identifier [Axis]: Ferrellgas, L.P. and Ferrellgas Partners L.P., Senior preferred units                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.96%   8.96%     8.96% 8.96% 8.96%      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 60.0   $ 60.0                
Investment, Identifier [Axis]: Ferrellgas, L.P., Senior preferred units                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.96%       8.96% 8.96% 8.96%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 55.7            
Investment, Identifier [Axis]: First Insight, Inc., Warrant to purchase units of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: First Insight, Inc., Warrant to purchase up to 122,827 units of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.5   14.5   10.0            
Less: funded commitments (6.2)   (6.2)   (4.9)            
Total unfunded commitments 8.3   8.3   5.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 8.3   $ 8.3   $ 5.1            
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.02% [2]   8.02% [2]   5.50% [1] 8.02% [2] 8.02% [2] 8.02% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 29.7 [3],[4]   $ 29.7 [3],[4]   $ 30.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 29.7 [3],[4]   $ 29.7 [3],[4]   $ 29.3 [6]            
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.02% [2]   8.02% [2]   5.50% [1] 8.02% [2] 8.02% [2] 8.02% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 1.1 [3],[4]   $ 1.1 [3],[4]   $ 1.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.1 [3],[4]   $ 1.1 [3],[4]   $ 1.1 [6]            
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.30% [2]   8.30% [2]   5.50% [1] 8.30% [2] 8.30% [2] 8.30% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 6.1 [3],[4],[13]   $ 6.1 [3],[4],[13]   $ 4.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.1 [3],[4],[13]   6.1 [3],[4],[13]   4.8 [6],[7]            
Investment, Identifier [Axis]: Flinn Scientific, Inc. and WCI-Quantum Holdings, Inc., Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.4 [4]   $ 1.4 [4]   $ 1.1 [7]            
Investment, Identifier [Axis]: Florida Food Products, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.12% [2]   8.12% [2]   5.75% [1] 8.12% [2] 8.12% [2] 8.12% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 14.3 [3],[4]   $ 14.3 [3],[4]   $ 4.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 13.8 [3],[4]   $ 13.8 [3],[4]   $ 4.3 [6],[7]            
Investment, Identifier [Axis]: Florida Food Products, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.03%   8.03%     8.03% 8.03% 8.03%      
Total first lien senior secured loans [3],[4] $ 0.4   $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.4   $ 0.4                
Investment, Identifier [Axis]: Florida Food Products, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.12% [2]   11.12% [2]   8.75% [1] 11.12% [2] 11.12% [2] 11.12% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 71.8 [3],[4]   $ 71.8 [3],[4]   $ 71.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 69.6 [3],[4]   69.6 [3],[4]   71.1 [6],[7]            
Investment, Identifier [Axis]: Flow Control Solutions, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         6.0            
Less: funded commitments         0.0            
Total unfunded commitments         6.0            
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 commitments         $ 6.0            
Investment, Identifier [Axis]: Flow Control Solutions, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6]         $ 10.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         10.8            
Investment, Identifier [Axis]: Forescout Technologies, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.2   14.2   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 14.2   14.2   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 14.2   14.2   0.1            
Investment, Identifier [Axis]: Forescout Technologies, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [6],[7]         18.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 18.5            
Investment, Identifier [Axis]: Forescout Technologies, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [3],[4] 23.2   23.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 23.2   23.2                
Investment, Identifier [Axis]: Forescout Technologies, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [3],[4] 12.3   12.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 12.3   $ 12.3                
Investment, Identifier [Axis]: Foundation Consumer Brands, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.43% [2]   8.43% [2]   7.38% [1] 8.43% [2] 8.43% [2] 8.43% [2] 7.38% [1] 7.38% [1] 7.38% [1]
Total first lien senior secured loans $ 13.0 [3],[4]   $ 13.0 [3],[4]   $ 24.9 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.0 [3],[4]   13.0 [3],[4]   24.8 [6]            
Investment, Identifier [Axis]: Foundation Risk Partners, Corp. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 48.7   48.7   38.1            
Less: funded commitments (1.1)   (1.1)   0.0            
Total unfunded commitments 47.6   47.6   38.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 47.6   $ 47.6   $ 38.1            
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.50% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 133.0 [3],[4]   $ 133.0 [3],[4]   $ 169.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 133.0 [3],[4]   $ 133.0 [3],[4]   167.7 [6],[7]            
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.75%   8.75%     8.75% 8.75% 8.75%      
Total first lien senior secured loans [3],[4] $ 33.2   $ 33.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 33.2   $ 33.2                
Investment, Identifier [Axis]: Foundation Risk Partners, Corp., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.74%   8.74%     8.74% 8.74% 8.74%      
Total first lien senior secured loans [3] $ 1.1   $ 1.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 1.1   1.1                
Investment, Identifier [Axis]: Frontline Technologies Group Holding LLC, Frontline Technologies Blocker Buyer, Inc., Frontline Technologies Holdings, LLC and Frontline Technologies Parent, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.2   7.2   6.7            
Investment, Identifier [Axis]: Frontline Technologies Group Holding LLC, Frontline Technologies Blocker Buyer, Inc., Frontline Technologies Holdings, LLC and Frontline Technologies Parent, LLC, Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.4   $ 8.4   $ 7.9            
Investment, Identifier [Axis]: Frontline Technologies Group Holding LLC, Frontline Technologies Blocker Buyer, Inc., Frontline Technologies Holdings, LLC and Frontline Technologies Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6]         $ 14.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 14.9            
Investment, Identifier [Axis]: Frontline Technologies Group Holding LLC, Frontline Technologies Blocker Buyer, Inc., Frontline Technologies Holdings, LLC and Frontline Technologies Parent, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.00%   11.00%     11.00% 11.00% 11.00%      
Total first lien senior secured loans [3],[4] $ 14.7   $ 14.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 14.7   $ 14.7                
Investment, Identifier [Axis]: Frontline Technologies Group Holding LLC, Frontline Technologies Blocker Buyer, Inc., Frontline Technologies Holdings, LLC and Frontline Technologies Parent, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.00% [2]   11.00% [2]   6.25% [1] 11.00% [2] 11.00% [2] 11.00% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   0.1 [6],[7]            
Investment, Identifier [Axis]: GF Parent LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: GF Parent LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: GF Parent LLC, Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: GHX Ultimate Parent Corporation, Commerce Parent, Inc. and Commerce Topco, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 47.5   47.5   47.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 47.5   47.5   47.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 47.5   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]                      
Total investments at fair value $ 28.5 [4]   $ 28.5 [4]   $ 32.2 [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 9.63% [2]   9.63% [2]   7.50% [1] 9.63% [2] 9.63% [2] 9.63% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 114.1 [3],[4]   $ 114.1 [3],[4]   $ 114.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 110.7 [3],[4]   110.7 [3],[4]   114.0 [6],[7]            
Investment, Identifier [Axis]: GI Ranger Intermediate LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.0   11.0   9.0            
Less: funded commitments (0.4)   (0.4)   0.0            
Total unfunded commitments 10.6   10.6   9.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 10.6   $ 10.6   $ 9.0            
Investment, Identifier [Axis]: GI Ranger Intermediate LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.70% [2]   9.70% [2]   6.75% [1] 9.70% [2] 9.70% [2] 9.70% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 40.2 [3],[4]   $ 40.2 [3],[4]   $ 35.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 39.8 [3],[4]   $ 39.8 [3],[4]   34.8 [6],[7]            
Investment, Identifier [Axis]: GI Ranger Intermediate LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.70%   9.70%     9.70% 9.70% 9.70%      
Total first lien senior secured loans [3],[4] $ 0.4   $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.4   0.4                
Investment, Identifier [Axis]: GNZ Energy Bidco Limited and Galileo Co-Investment | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.8   2.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.8   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 commitments 2.8   2.8                
Investment, Identifier [Axis]: GNZ Energy Bidco Limited and Galileo Co-investment Trust I, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 9.9   $ 9.9                
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 [2] 10.65%   10.65%     10.65% 10.65% 10.65%      
Total first lien senior secured loans [3],[4],[5] $ 27.3   $ 27.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 26.8   26.8                
Investment, Identifier [Axis]: GPM Investments, LLC and ARKO Corp., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 25.5   25.5   18.3            
Investment, Identifier [Axis]: GPM Investments, LLC and ARKO Corp., Warrant to purchase common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         1.9            
Investment, Identifier [Axis]: GPM Investments, LLC and ARKO Corp., Warrant to purchase up to 1,088,780 units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 1.9   1.9                
Investment, Identifier [Axis]: GSV PracticeTek Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 13.6   13.6                
Investment, Identifier [Axis]: Galway Borrower LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.2   14.2   23.3            
Less: funded commitments (0.4)   (0.4)   (0.4)            
Total unfunded commitments 13.8   13.8   22.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 13.8   $ 13.8   $ 22.9            
Investment, Identifier [Axis]: Galway Borrower LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.92% [2]   8.92% [2]   6.00% [1] 8.92% [2] 8.92% [2] 8.92% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 31.7 [3],[4]   $ 31.7 [3],[4]   $ 59.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 31.0 [3],[4]   $ 31.0 [3],[4]   $ 58.5 [6],[7]            
Investment, Identifier [Axis]: Galway Borrower LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.92%   8.92%     8.92% 8.92% 8.92%      
Total first lien senior secured loans [3] $ 4.2   $ 4.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 4.1   4.1                
Investment, Identifier [Axis]: Galway Borrower LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Garden Fresh Restaurant Corp. and GFRC Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         7.5            
Less: funded commitments         (7.5)            
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 commitments         0.0            
Investment, Identifier [Axis]: Garden Fresh Restaurant Corp. and GFRC Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7],[10]         21.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[10]         0.0            
Investment, Identifier [Axis]: Garden Fresh Restaurant Corp. and GFRC Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7],[10]         7.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[10]         0.0            
Investment, Identifier [Axis]: Gehl Foods, LLC and GF Parent LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Gehl Foods, LLC and GF Parent LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Gehl Foods, LLC and GF Parent LLC, Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.5   1.5   1.5            
Less: funded commitments (1.5)   (1.5)   (1.5)            
Total unfunded commitments 0.0   0.0   0.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   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]                      
Total investments at fair value $ 1.4 [4]   $ 1.4 [4]   $ 0.9 [7]            
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.25%       5.25% 5.25% 5.25%
Total first lien senior secured loans [6],[7]         $ 9.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 9.0            
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.42%   8.42%     8.42% 8.42% 8.42%      
Total first lien senior secured loans [3],[4] $ 9.0   $ 9.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 9.0   $ 9.0                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.92% [2]   7.92% [2]   4.22% [1] 7.92% [2] 7.92% [2] 7.92% [2] 4.22% [1] 4.22% [1] 4.22% [1]
Total first lien senior secured loans $ 0.2 [4]   $ 0.2 [4]   $ 0.2 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.2 [4]   $ 0.2 [4]   $ 0.2 [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 7.92% [2]   7.92% [2]   4.22% [1] 7.92% [2] 7.92% [2] 7.92% [2] 4.22% [1] 4.22% [1] 4.22% [1]
Total first lien senior secured loans $ 1.5 [4]   $ 1.5 [4]   $ 1.5 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.5 [4]   $ 1.5 [4]   $ 1.5 [7]            
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.25%       8.25% 8.25% 8.25%
Total first lien senior secured loans [6],[7]         $ 21.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 20.7            
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Second lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.79%   9.79%     9.79% 9.79% 9.79%      
Total first lien senior secured loans [4] $ 32.4   $ 32.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 32.0   $ 32.0                
Investment, Identifier [Axis]: Genesis Acquisition Co. and Genesis Ultimate Holding Co., Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.79% [2]   9.79% [2]   7.63% [1] 9.79% [2] 9.79% [2] 9.79% [2] 7.63% [1] 7.63% [1] 7.63% [1]
Total first lien senior secured loans $ 21.1 [3],[4]   $ 21.1 [3],[4]   $ 32.4 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 20.9 [3],[4]   $ 20.9 [3],[4]   $ 31.4 [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 9.79% [2]   9.79% [2]   7.70% [1] 9.79% [2] 9.79% [2] 9.79% [2] 7.70% [1] 7.70% [1] 7.70% [1]
Total first lien senior secured loans $ 7.5 [4]   $ 7.5 [4]   $ 7.5 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.4 [4]   7.4 [4]   7.3 [7]            
Investment, Identifier [Axis]: Genomatica, Inc., Warrant to purchase 322,422 shares of Series D preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Genomatica, Inc., Warrant to purchase shares of Series D preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at 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 [2] 7.37%   7.37%     7.37% 7.37% 7.37%      
Total first lien senior secured loans [3],[4],[11] $ 10.8   $ 10.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] $ 9.3   $ 9.3                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.81%   6.81%     6.81% 6.81% 6.81%      
Total first lien senior secured loans [3],[4],[11] $ 25.2   $ 25.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] $ 21.8   $ 21.8                
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.76% [2]   9.76% [2]   7.50% [1] 9.76% [2] 9.76% [2] 9.76% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 95.4 [3],[4]   $ 95.4 [3],[4]   $ 95.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 83.0 [3],[4]   83.0 [3],[4]   94.5 [6],[7]            
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., Warrant to purchase units of common stock 1                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         3.0            
Investment, Identifier [Axis]: Global Medical Response, Inc. and GMR Buyer Corp., Warrant to purchase units of common stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
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]                      
Total investments at fair value [4] 0.0   0.0                
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]                      
Total investments at fair value [4] 2.2   2.2                
Investment, Identifier [Axis]: Global Music Rights, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.3   4.3   4.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.3   4.3   4.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.3   $ 4.3   $ 4.3            
Investment, Identifier [Axis]: Global Music Rights, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.50% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 22.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   22.1 [6],[7]            
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 33.8   33.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 33.8   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 0.0   0.0                
Total net adjusted unfunded revolving and delayed draw commitments $ 33.8   $ 33.8                
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.18%   10.18%     10.18% 10.18% 10.18%      
Total first lien senior secured loans [3],[4] $ 17.7   $ 17.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 17.5   $ 17.5                
Investment, Identifier [Axis]: Gotham Greens Holdings, PBC, Series E-1 preferred stock                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 600.00%   600.00%     600.00% 600.00% 600.00%      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 14.2   $ 14.2                
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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: GraphPAD Software, LLC, Insightful Science Intermediate I, LLC and Insightful Science Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0   5.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 5.0   5.0   5.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 5.0   $ 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 [2] 7.00%   7.00%     7.00% 7.00% 7.00%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.2   $ 0.2                
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 [2] 9.17%   9.17%     9.17% 9.17% 9.17%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.1   $ 0.1                
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 [2] 9.17%   9.17%     9.17% 9.17% 9.17%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.1   $ 0.1                
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 [2] 8.31%   8.31%     8.31% 8.31% 8.31%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
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]                      
Total investments at fair value 57.5   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 [4] 43.5   43.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 41.6   41.6                
Investment, Identifier [Axis]: Green Street Parent, LLC and Green Street Intermediate Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.3   0.3   0.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.3   0.3   0.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.3   $ 0.3   $ 0.3            
Investment, Identifier [Axis]: Green Street Parent, LLC and Green Street Intermediate Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   6.50% [1] 8.62% [2] 8.62% [2] 8.62% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 23.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   23.7 [6],[7]            
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.9   $ 3.9   $ 6.8            
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.21% [2]   6.21% [2]   6.00% [1] 6.21% [2] 6.21% [2] 6.21% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 26.4 [4],[11]   $ 26.4 [4],[11]   $ 75.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 20.5 [4],[11]   $ 20.5 [4],[11]   $ 75.0 [6],[7]            
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.52%   6.52%     6.52% 6.52% 6.52%      
Total first lien senior secured loans [4],[11] $ 3.3   $ 3.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[11] $ 2.6   $ 2.6                
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.52%   7.52%     7.52% 7.52% 7.52%      
Total first lien senior secured loans [3],[4],[11] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] $ 0.1   $ 0.1                
Investment, Identifier [Axis]: H-Food Holdings, LLC and Matterhorn Parent, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.12% [2]   10.12% [2]   7.10% [1] 10.12% [2] 10.12% [2] 10.12% [2] 7.10% [1] 7.10% [1] 7.10% [1]
Total first lien senior secured loans $ 73.0 [4]   $ 73.0 [4]   $ 73.0 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 61.3 [4]   61.3 [4]   73.0 [7]            
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.0   19.0   19.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 19.0   19.0   19.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 19.0   19.0   19.0            
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.5 [4]   $ 2.5 [4]   $ 2.3 [7]            
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.37% [2]   8.37% [2]   6.00% [1] 8.37% [2] 8.37% [2] 8.37% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 60.7 [3],[4]   $ 60.7 [3],[4]   $ 61.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 60.7 [3],[4]   $ 60.7 [3],[4]   $ 61.0 [6]            
Investment, Identifier [Axis]: HAI Acquisition Corporation and Aloha Topco, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.37% [2]   8.37% [2]   6.00% [1] 8.37% [2] 8.37% [2] 8.37% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   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   (0.1)            
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: HCI Equity, LLC, Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [5],[11]   0.0 [5],[11]   0.0 [8],[12]            
Investment, Identifier [Axis]: HGC Holdings, LLC | Revolving and delayed draw loan commitments                      
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 commitments 7.5   7.5                
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.9   15.9   18.1            
Less: funded commitments (2.3)   (2.3)   (0.5)            
Total unfunded commitments 13.6   13.6   17.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 13.6   13.6   17.6            
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.3 [4]   $ 2.3 [4]   $ 2.9 [7]            
Investment, Identifier [Axis]: HH-Stella, Inc. and Bedrock Parent Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.00% [2]   9.00% [2]   6.50% [1] 9.00% [2] 9.00% [2] 9.00% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 4.7 [3],[4]   $ 4.7 [3],[4]   $ 2.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.6 [3],[4]   $ 4.6 [3],[4]   $ 2.6 [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 8.63% [2]   8.63% [2]   6.50% [1] 8.63% [2] 8.63% [2] 8.63% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 2.3 [3],[4]   $ 2.3 [3],[4]   $ 0.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.2 [3],[4]   2.2 [3],[4]   0.5 [6],[7]            
Investment, Identifier [Axis]: Halcon Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.9   2.9   6.8            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.9   2.9   6.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.9   $ 2.9   $ 6.8            
Investment, Identifier [Axis]: Halcon Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.67% [2]   10.67% [2]   7.17% [1] 10.67% [2] 10.67% [2] 10.67% [2] 7.17% [1] 7.17% [1] 7.17% [1]
Total first lien senior secured loans $ 10.5 [4]   $ 10.5 [4]   $ 19.0 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 10.5 [4]   10.5 [4]   18.9 [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            
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: Halex Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: Harvey Tool Company, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.5   28.5   29.5            
Less: funded commitments 0.0   0.0   (5.9)            
Total unfunded commitments 28.5   28.5   23.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 28.5   $ 28.5   $ 23.6            
Investment, Identifier [Axis]: Harvey Tool Company, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.11% [2]   9.11% [2]   6.25% [1] 9.11% [2] 9.11% [2] 9.11% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 23.5 [3],[4]   $ 23.5 [3],[4]   $ 22.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 23.3 [3],[4]   23.3 [3],[4]   $ 22.5 [6],[7]            
Investment, Identifier [Axis]: Harvey Tool Company, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[7],[14]         $ 5.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   5.8 [6],[7],[14]            
Investment, Identifier [Axis]: HealthEdge Sgoftware, Inc., First lien senior secured loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         79.2            
Investment, Identifier [Axis]: HealthEdge Software, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 36.7   36.7   42.3            
Less: funded commitments (0.3)   (0.3)   (0.3)            
Total unfunded commitments 36.4   36.4   42.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 36.4   $ 36.4   $ 42.0            
Investment, Identifier [Axis]: HealthEdge Software, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.48% [2]   10.48% [2]   7.25% [1] 10.48% [2] 10.48% [2] 10.48% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 84.8 [3],[4]   $ 84.8 [3],[4]   $ 79.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 84.8   84.8                
Investment, Identifier [Axis]: HealthEdge Software, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Heavy Construction Systems Specialists, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0   4.0   4.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.0   4.0   4.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.0   $ 4.0   $ 4.0            
Investment, Identifier [Axis]: Heavy Construction Systems Specialists, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.02% [2]   8.02% [2]   6.50% [1] 8.02% [2] 8.02% [2] 8.02% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 40.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   40.5 [6],[7]            
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         41.7            
Redemptions (cost)         8.5            
Sales (cost)         0.0            
Interest income         1.5            
Capital structuring service fees         0.7            
Dividend income         0.4            
Other income         0.0            
Net realized gains (losses):         0.2            
Net unrealized gains (losses):         9.3            
Total investments at fair value         69.4            
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         51.0            
Less: funded commitments         0.0            
Total unfunded commitments         51.0            
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 commitments         51.0            
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     95.4                
Redemptions (cost)     0.0                
Sales (cost)     0.0                
Interest income     5.0                
Capital structuring service fees     1.7                
Dividend income     0.0                
Other income     0.0                
Net realized gains (losses):     0.0                
Net unrealized gains (losses):     32.6                
Total investments at fair value 191.5   191.5                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC | Revolving and delayed draw loan commitments                      
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 commitments 8.5   8.5                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC, Class A1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 81.0   81.0                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC, Class A2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.0   $ 4.0                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC and Heelstone Renewable Energy Investors, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.75%   10.75%     10.75% 10.75% 10.75%      
Total first lien senior secured loans [3],[4] $ 106.5   $ 106.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 106.5   106.5                
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC, Class A1 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 30.4            
Investment, Identifier [Axis]: Heelstone Renewable Energy, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [6],[7]         $ 39.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         39.0            
Investment, Identifier [Axis]: Help/Systems Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         7.5            
Less: funded commitments         0.0            
Total unfunded commitments         7.5            
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 commitments         7.5            
Investment, Identifier [Axis]: Help/Systems Holdings, Inc. | Revolving and delayed draw loan commitments                      
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 commitments 7.5   7.5                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 33.3   33.3   8.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 33.3   33.3   8.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 33.3   $ 33.3   $ 8.0            
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.81% [2]   8.81% [2]   6.75% [1] 8.81% [2] 8.81% [2] 8.81% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 34.6 [3],[4]   $ 34.6 [3],[4]   $ 55.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 34.2 [3],[4]   $ 34.2 [3],[4]   $ 54.5 [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 8.83% [2]   8.83% [2]   6.75% [1] 8.83% [2] 8.83% [2] 8.83% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 12.3 [3],[4]   $ 12.3 [3],[4]   $ 10.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 12.2 [3],[4]   $ 12.2 [3],[4]   10.3 [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 [2] 8.21%   8.21%     8.21% 8.21% 8.21%      
Total first lien senior secured loans [3],[4] $ 6.9   $ 6.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 6.8   6.8                
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, Series A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.0 [4]   7.0 [4]   11.1 [7]            
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, Series A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 102.5 [4]   102.5 [4]   101.2 [7]            
Investment, Identifier [Axis]: High Street Buyer, Inc. and High Street Holdco LLC, Series C common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 7.5 [4]   $ 7.5 [4]   11.9 [7]            
Investment, Identifier [Axis]: HighTower Holding, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.75%   6.75%     6.75% 6.75% 6.75%      
Total first lien senior secured loans [4],[5] $ 8.1   $ 8.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 6.6   6.6                
Investment, Identifier [Axis]: Highline Aftermarket Acquisition, LLC, Highline Aftermarket SC Acquisition, Inc. and Highline PPC Blocker LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.5   9.5   9.5            
Less: funded commitments (1.2)   (1.2)   (5.9)            
Total unfunded commitments 8.3   8.3   3.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 8.3   8.3   3.6            
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]                      
Total investments at fair value $ 3.6 [4]   $ 3.6 [4]   $ 3.5 [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 [2] 7.62%   7.62%     7.62% 7.62% 7.62%      
Total first lien senior secured loans [3],[4],[11] $ 12.0   $ 12.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] $ 10.7   $ 10.7                
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 6.87% [2]   6.87% [2]   3.85% [1] 6.87% [2] 6.87% [2] 6.87% [2] 3.85% [1] 3.85% [1] 3.85% [1]
Total first lien senior secured loans $ 1.0 [4],[13]   $ 1.0 [4],[13]   $ 5.9 [7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.9 [4],[13]   $ 0.9 [4],[13]   $ 5.8 [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 10.24% [2]   10.24% [2]   8.75% [1] 10.24% [2] 10.24% [2] 10.24% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 70.4 [3],[4]   $ 70.4 [3],[4]   $ 70.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 62.6 [3],[4]   62.6 [3],[4]   66.1 [6],[7]            
Investment, Identifier [Axis]: Hometown Food Company | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9   3.9            
Less: funded commitments (0.7)   (0.7)   0.0            
Total unfunded commitments 3.2   3.2   3.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.2   $ 3.2   $ 3.9            
Investment, Identifier [Axis]: Hometown Food Company, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.12%   8.12%     8.12% 8.12% 8.12%      
Total first lien senior secured loans [3],[4],[13] $ 0.7   $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[13] $ 0.7   $ 0.7                
Investment, Identifier [Axis]: Honor Technology, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.63% [2]   12.63% [2]   11.00% [1] 12.63% [2] 12.63% [2] 12.63% [2] 11.00% [1] 11.00% [1] 11.00% [1]
Total first lien senior secured loans $ 2.5 [3],[4]   $ 2.5 [3],[4]   $ 2.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.4 [3],[4]   2.4 [3],[4]   2.5 [6],[7]            
Investment, Identifier [Axis]: Honor Technology, Inc., Warrant to purchase shares of series D-2 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.1            
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]                      
Total investments at fair value [4] 0.0   0.0                
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.6   22.6   22.6            
Less: funded commitments (7.0)   (7.0)   (1.6)            
Total unfunded commitments 15.6   15.6   21.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 15.6   15.6   $ 21.0            
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC and GI Insurity TopCo LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 6.1   $ 6.1                
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 8.64% [2]   8.64% [2]   6.25% [1] 8.64% [2] 8.64% [2] 8.64% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 60.5 [3],[4]   $ 60.5 [3],[4]   $ 105.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 56.3 [3],[4]   $ 56.3 [3],[4]   $ 104.8 [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 9.17% [2]   9.17% [2]   6.25% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 7.0 [3],[4]   $ 7.0 [3],[4]   $ 1.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.5 [3],[4]   6.5 [3],[4]   1.4 [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 97.1 [4]   97.1 [4]   90.2 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 86.4 [4]   86.4 [4]   88.8 [7]            
Investment, Identifier [Axis]: Huskies Parent, Inc., GI Insurity Parent LLC, and GI Insurity Topco LP, Company units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         8.8            
Investment, Identifier [Axis]: IQN Holding Corp. | Revolving and delayed draw loan commitments                      
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 commitments $ 7.2   $ 7.2                
Investment, Identifier [Axis]: IQN Holding Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.41%   8.41%     8.41% 8.41% 8.41%      
Total first lien senior secured loans [3],[4] $ 23.6   $ 23.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 23.3   23.3                
Investment, Identifier [Axis]: IRI Holdings, Inc., IRI Group Holdings, Inc. and IRI Parent, L.P., Class A-1 common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 26.1            
Investment, Identifier [Axis]: IRI Holdings, Inc., IRI Group Holdings, Inc. and IRI Parent, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         4.35%       4.35% 4.35% 4.35%
Total first lien senior secured loans         $ 42.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 42.3            
Investment, Identifier [Axis]: IRI Holdings, Inc., IRI Group Holdings, Inc. and IRI Parent, L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.10%       8.10% 8.10% 8.10%
Total first lien senior secured loans [7]         $ 86.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         86.8            
Investment, Identifier [Axis]: IRI Holdings, Inc., IRI Group Holdings, Inc. and IRI Parent, L.P., Series A-1 preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         66.0            
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.8   12.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 12.8   12.8                
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 commitments 12.8   12.8                
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, LLC , Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 10.0   $ 10.0                
Investment, Identifier [Axis]: ISQ Hawkeye Holdco, Inc. and ISQ Hawkeye Holdings, LLC , First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.31%   9.31%     9.31% 9.31% 9.31%      
Total first lien senior secured loans [3],[4] $ 12.5   $ 12.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 12.3   12.3                
Investment, Identifier [Axis]: ITI Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.7   5.7                
Less: funded commitments (1.8)   (1.8)                
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 commitments $ 3.9   $ 3.9                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.52%   8.52%     8.52% 8.52% 8.52%      
Total first lien senior secured loans [3],[4] $ 38.2   $ 38.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 37.9   $ 37.9                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.25%   8.25%     8.25% 8.25% 8.25%      
Total first lien senior secured loans [3],[4] $ 1.1   $ 1.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.1   $ 1.1                
Investment, Identifier [Axis]: ITI Holdings, Inc., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.75%   10.75%     10.75% 10.75% 10.75%      
Total first lien senior secured loans [3] $ 0.7   $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 0.7   0.7                
Investment, Identifier [Axis]: IV Rollover Holdings, LLC, Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.1 [7]            
Investment, Identifier [Axis]: IV Rollover Holdings, LLC, Class X units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.1 [4]   2.1 [4]   2.2 [7]            
Investment, Identifier [Axis]: IfByPhone Inc., Warrant to purchase shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: IfByPhone Inc., Warrant to purchase up to 124,300 shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
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)     3.9   0.0            
Sales (cost)     0.0   0.0            
Interest income     1.8   2.4            
Capital structuring service fees     0.6   0.0            
Dividend income     22.9   0.0            
Other income     0.4   0.6            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     4.7   8.4            
Total investments at fair value 57.8   57.8   53.0            
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation, Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2   0.2   0.2            
Investment, Identifier [Axis]: Imaging Business Machines, L.L.C. and Scanner Holdings Corporation, Class B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.9   $ 1.9   $ 1.4            
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% [2]   14.00% [2]   14.00% [1] 14.00% [2] 14.00% [2] 14.00% [2] 14.00% [1] 14.00% [1] 14.00% [1]
Total first lien senior secured loans $ 16.6 [4]   $ 16.6 [4]   $ 16.6 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 16.6 [4]   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]                      
Total investments at fair value $ 39.1   $ 39.1   $ 34.8            
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.67% [2]   11.67% [2]   8.75% [1] 11.67% [2] 11.67% [2] 11.67% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 117.0 [3],[4]   $ 117.0 [3],[4]   $ 103.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 105.3 [3],[4]   $ 105.3 [3],[4]   $ 95.1 [6],[7]            
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.67% [2]   11.67% [2]   8.75% [1] 11.67% [2] 11.67% [2] 11.67% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 5.0 [3],[4]   $ 5.0 [3],[4]   $ 14.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.5 [3],[4]   $ 4.5 [3],[4]   $ 13.0 [6],[7]            
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.67% [2]   11.67% [2]   8.75% [1] 11.67% [2] 11.67% [2] 11.67% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 1.3 [3],[4]   $ 1.3 [3],[4]   $ 1.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.1 [3],[4]   $ 1.1 [3],[4]   $ 1.2 [6],[7]            
Investment, Identifier [Axis]: Implus Footcare, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.75%       8.75% 8.75% 8.75%
Total first lien senior secured loans [6],[7]         $ 5.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 4.6            
Investment, Identifier [Axis]: Imprivata, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.28%   9.28%     9.28% 9.28% 9.28%      
Total first lien senior secured loans [3],[4] $ 16.1   $ 16.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 15.3   $ 15.3                
Investment, Identifier [Axis]: Inmar, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.12% [2]   11.12% [2]   9.00% [1] 11.12% [2] 11.12% [2] 11.12% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 28.3 [3],[4]   $ 28.3 [3],[4]   $ 28.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 27.7 [3],[4]   27.7 [3],[4]   $ 28.3 [6],[7]            
Investment, Identifier [Axis]: Insightful Science, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 0.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.5            
Investment, Identifier [Axis]: Insightful Science, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 16.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 16.0            
Investment, Identifier [Axis]: Insightful Science, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 7.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 7.9            
Investment, Identifier [Axis]: Insightful Science, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 7.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         7.5            
Investment, Identifier [Axis]: Insightful Science, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         50.5            
Investment, Identifier [Axis]: Insightful Science, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]         39.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         38.8            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Common stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 0.0            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.50%       10.50% 10.50% 10.50%
Total first lien senior secured loans [6],[7]         $ 4.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         4.0            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Senior preferred series A-1 shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         36.4            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Series B preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Series B preferred stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Instituto de Banca y Comercio, Inc. & Leeds IV Advisors, Inc., Series C preferred stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: IntraPac International LLC and IntraPac Canada Corporation | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         19.2            
Less: funded commitments         (6.2)            
Total unfunded commitments         13.0            
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 commitments         $ 13.0            
Investment, Identifier [Axis]: IntraPac International LLC and IntraPac Canada Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[8]         $ 14.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[8]         $ 14.8            
Investment, Identifier [Axis]: IntraPac International LLC and IntraPac Canada Corporation, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[7],[8]         $ 10.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 10.8            
Investment, Identifier [Axis]: IntraPac International LLC and IntraPac Canada Corporation, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[7],[8]         $ 6.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         6.2            
Investment, Identifier [Axis]: Ivy Hill Asset Management, L.P.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     1,260.9   347.5            
Redemptions (cost)     233.2   70.5            
Sales (cost)     0.0   37.0            
Interest income     11.0   2.9            
Capital structuring service fees     0.0   0.0            
Dividend income     150.0   93.0            
Other income     0.0   0.0            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     (5.2)   67.3            
Total investments at fair value 1,958.2   1,958.2   935.8            
Investment, Identifier [Axis]: Ivy Hill Asset Management, L.P., Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1,522.1   $ 1,522.1   $ 919.8 [8]            
Investment, Identifier [Axis]: Ivy Hill Asset Management, L.P., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.56% [2]   9.56% [2]   7.25% [1] 9.56% [2] 9.56% [2] 9.56% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 436.1 [3],[5]   $ 436.1 [3],[5]   $ 16.0 [6],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 436.1 [3],[5]   436.1 [3],[5]   16.0 [6],[8]            
Investment, Identifier [Axis]: JDC Healthcare Management, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.7   4.7   4.4            
Less: funded commitments (4.7)   (4.7)   (4.4)            
Total unfunded commitments 0.0   0.0   0.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   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 39.7 [4],[9]   39.7 [4],[9]   37.2 [7],[10]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 22.2 [4],[9]   22.2 [4],[9]   26.5 [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 4.7 [4],[9]   4.7 [4],[9]   4.4 [7],[10]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.6 [4],[9]   2.6 [4],[9]   3.1 [7],[10]            
Investment, Identifier [Axis]: JWC/KI Holdings, LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.7 [4]   7.7 [4]   7.7 [7]            
Investment, Identifier [Axis]: Javlin Three LLC, Javlin Four LLC, and Javlin Five LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 15.4 [4],[5],[9]   15.4 [4],[5],[9]   15.7 [7],[8],[10]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [4],[5],[9]   0.0 [4],[5],[9]   0.4 [7],[8],[10]            
Investment, Identifier [Axis]: Jenny C Acquisition, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 1.5 [4]   1.5 [4]   1.4 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.5 [4]   $ 1.5 [4]   1.4 [7]            
Investment, Identifier [Axis]: Jim N Nicks Management, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         4.8            
Less: funded commitments         (2.8)            
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 commitments         $ 2.0            
Investment, Identifier [Axis]: Jim N Nicks Management, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6]         $ 14.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 14.7            
Investment, Identifier [Axis]: Jim N Nicks Management, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[7]         $ 2.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         2.8            
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.99%   9.99%     9.99% 9.99% 9.99%      
Total first lien senior secured loans [3],[4] $ 19.2   $ 19.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 18.6   18.6                
Investment, Identifier [Axis]: Johnnie-O Inc. and Johnnie-O Holdings Inc., Series A convertible preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 4.5   4.5                
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]                      
Total investments at fair value [4] 2.2   2.2                
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   0.0            
Redemptions (cost)     0.3   0.3            
Sales (cost)     0.0   0.0            
Interest income     0.1   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            
Total investments at fair value 0.0   0.0   0.3            
Investment, Identifier [Axis]: Joyce Lane Capital LLC and Joyce Lane Financing SPV LLC (fka Ciena Capital LLC) | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         1.4            
Less: funded commitments         0.0            
Total unfunded commitments         1.4            
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 commitments         1.4            
Investment, Identifier [Axis]: Joyce Lane Capital LLC and Joyce Lane Financing SPV LLC (fka Ciena Capital LLC), Equity interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [5]   0.0 [5]   $ 0.0 [7],[8]            
Investment, Identifier [Axis]: Joyce Lane Capital LLC and Joyce Lane Financing SPV LLC (fka Ciena Capital LLC), First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         4.13%       4.13% 4.13% 4.13%
Total first lien senior secured loans [7],[8]         $ 0.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         0.3            
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.1   9.1   10.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 9.1   9.1   10.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 9.1   9.1   10.9            
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.8 [4]   $ 2.8 [4]   $ 1.6 [7]            
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.67% [2]   8.67% [2]   6.00% [1] 8.67% [2] 8.67% [2] 8.67% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 50.6 [3],[4]   $ 50.6 [3],[4]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 50.6 [3],[4]   $ 50.6 [3],[4]   $ 0.6 [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 8.67% [2]   8.67% [2]   6.00% [1] 8.67% [2] 8.67% [2] 8.67% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 2.3 [3],[4]   $ 2.3 [3],[4]   $ 51.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.3 [3],[4]   $ 2.3 [3],[4]   $ 51.0 [6]            
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.27% [2]   8.27% [2]   6.00% [1] 8.27% [2] 8.27% [2] 8.27% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 0.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [3],[4]   0.2 [3],[4]   $ 0.2 [6],[7]            
Investment, Identifier [Axis]: K2 Insurance Services, LLC and K2 Holdco LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: KBHS Acquisition, LLC (d/b/a Alita Care, LLC) | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0   5.0            
Less: funded commitments (1.8)   (1.8)   (0.8)            
Total unfunded commitments 3.2   3.2   4.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.2   $ 3.2   $ 4.2            
Investment, Identifier [Axis]: KBHS Acquisition, LLC (d/b/a Alita Care, LLC), First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.88%   7.88%     7.88% 7.88% 7.88%      
Total first lien senior secured loans [3],[4] $ 1.8   $ 1.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.8   $ 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 | Rate [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6],[7]         $ 0.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.8            
Investment, Identifier [Axis]: KC Culinarte Intermediate, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.87% [2]   6.87% [2]   4.75% [1] 6.87% [2] 6.87% [2] 6.87% [2] 4.75% [1] 4.75% [1] 4.75% [1]
Total first lien senior secured loans $ 28.9 [3]   $ 28.9 [3]   $ 29.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 27.4 [3]   $ 27.4 [3]   $ 27.6 [6]            
Investment, Identifier [Axis]: KC Culinarte Intermediate, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.87% [2]   10.87% [2]   8.75% [1] 10.87% [2] 10.87% [2] 10.87% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 35.7 [3],[4]   $ 35.7 [3],[4]   $ 35.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 32.8 [3],[4]   $ 32.8 [3],[4]   32.0 [6],[7]            
Investment, Identifier [Axis]: KNPC HoldCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.47%   8.47%     8.47% 8.47% 8.47%      
Total first lien senior secured loans [3] $ 5.6   $ 5.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 5.5   5.5                
Investment, Identifier [Axis]: KPS Global LLC and Cool Group LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.3   $ 3.3   $ 0.9            
Investment, Identifier [Axis]: KPS Global LLC and Cool Group LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.53% [2]   8.53% [2]   7.00% [1] 8.53% [2] 8.53% [2] 8.53% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 12.6 [3],[4]   $ 12.6 [3],[4]   $ 12.6 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 12.6 [3],[4]   $ 12.6 [3],[4]   $ 12.3 [6]            
Investment, Identifier [Axis]: KPS Global LLC and Cool Group LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.53% [2]   8.53% [2]   7.00% [1] 8.53% [2] 8.53% [2] 8.53% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 3.4 [3],[4]   $ 3.4 [3],[4]   $ 3.4 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.4 [3],[4]   3.4 [3],[4]   3.3 [6]            
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc, Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 38.0   38.0                
Investment, Identifier [Axis]: Kaseya Inc. and Knockout Intermediate Holdings I Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 31.2   31.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 31.2   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 commitments $ 31.2   $ 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 [2] 8.29%   8.29%     8.29% 8.29% 8.29%      
Total first lien senior secured loans [3],[4] $ 167.0   $ 167.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 163.7   $ 163.7                
Investment, Identifier [Axis]: Kellermeyer Bergensons Services, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         23.0            
Less: funded commitments         0.0            
Total unfunded commitments         23.0            
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 commitments         $ 23.0            
Investment, Identifier [Axis]: Kellermeyer Bergensons Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.81% [2]   8.81% [2]   6.75% [1] 8.81% [2] 8.81% [2] 8.81% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 81.9 [3],[4]   $ 81.9 [3],[4]   $ 60.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 78.6 [3],[4]   $ 78.6 [3],[4]   $ 60.8 [6],[7]            
Investment, Identifier [Axis]: Kellermeyer Bergensons Services, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.81% [2]   8.81% [2]   6.75% [1] 8.81% [2] 8.81% [2] 8.81% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 21.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   21.1 [6],[7]            
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.9   8.9   8.9            
Less: funded commitments (0.2)   (0.2)   (0.2)            
Total unfunded commitments 8.7   8.7   8.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 8.7   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]                      
Total investments at fair value $ 5.7 [4]   $ 5.7 [4]   $ 5.3 [7]            
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.92% [2]   7.92% [2]   5.25% [1] 7.92% [2] 7.92% [2] 7.92% [2] 5.25% [1] 5.25% [1] 5.25% [1]
Total first lien senior secured loans $ 40.7 [3],[4]   $ 40.7 [3],[4]   $ 41.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 40.3 [3],[4]   40.3 [3],[4]   $ 41.1 [6]            
Investment, Identifier [Axis]: Kene Acquisition, Inc. and Kene Holdings, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: KeyStone Sub-debt HoldCo, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 58.5 [4]   58.5 [4]   54.3 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 58.5 [4]   58.5 [4]   52.7 [7]            
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 [4]   7.8 [4]   7.2 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.8 [4]   7.8 [4]   7.0 [7]            
Investment, Identifier [Axis]: KeyStone Sub-debt HoldCo, LLC, Warrant to purchase Class C interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         4.2            
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]                      
Total investments at fair value [4] 8.6   8.6                
Investment, Identifier [Axis]: LJP Purchaser, Inc. and LJP Topco, LP | Revolving and delayed draw loan commitments                      
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 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]                      
Total investments at fair value [4] $ 5.1   $ 5.1                
Investment, Identifier [Axis]: LJP Purchaser, Inc. and LJP Topco, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.16%   9.16%     9.16% 9.16% 9.16%      
Total first lien senior secured loans [3],[4] $ 8.5   $ 8.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 8.3   8.3                
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.2 [5]   $ 3.2 [5]   $ 3.5 [8]            
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.50%       10.50% 10.50% 10.50%
Total first lien senior secured loans [7],[8]         $ 37.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         $ 37.0            
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Senior subordinated loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.50%   10.50%     10.50% 10.50% 10.50%      
Total first lien senior secured loans [4],[5] $ 3.0   $ 3.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 3.0   $ 3.0                
Investment, Identifier [Axis]: LS DE LLC and LM LSQ Investors LLC, Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.50% [2]   10.50% [2]   10.50% [1] 10.50% [2] 10.50% [2] 10.50% [2] 10.50% [1] 10.50% [1] 10.50% [1]
Total first lien senior secured loans $ 37.0 [4],[5]   $ 37.0 [4],[5]   $ 3.0 [7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 37.0 [4],[5]   37.0 [4],[5]   3.0 [7],[8]            
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.1   19.1   16.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 19.1   19.1   16.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 19.1   $ 19.1   $ 16.2            
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 8.80% [2]   8.80% [2]   7.00% [1] 8.80% [2] 8.80% [2] 8.80% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 12.7 [3],[4]   $ 12.7 [3],[4]   $ 6.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 12.5 [3],[4]   $ 12.5 [3],[4]   6.8 [6],[7]            
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] 8.26%   8.26%     8.26% 8.26% 8.26%      
Total first lien senior secured loans [3],[4] $ 6.3   $ 6.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 6.2   $ 6.2                
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] 8.81%   8.81%     8.81% 8.81% 8.81%      
Total first lien senior secured loans [3],[4] $ 5.0   $ 5.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 4.9   4.9                
Investment, Identifier [Axis]: LSP Holdco, LLC and ZBS Mechanical Group Co-Invest Fund 2, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 14.4   14.4   2.8            
Investment, Identifier [Axis]: LTG Acquisition, Inc., Class A membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 41.3   41.3   44.6            
Less: funded commitments (3.9)   (3.9)   0.0            
Total unfunded commitments 37.4   37.4   44.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 37.4   37.4   44.6            
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.7 [4]   $ 4.7 [4]   $ 4.1 [7]            
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6]         $ 21.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 21.6            
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.49%   8.49%     8.49% 8.49% 8.49%      
Total first lien senior secured loans [3],[4] $ 23.2   $ 23.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 22.5   $ 22.5                
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.70% [2]   8.70% [2]   6.75% [1] 8.70% [2] 8.70% [2] 8.70% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 16.7 [3]   $ 16.7 [3]   $ 25.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 16.2 [3]   $ 16.2 [3]   $ 25.5 [6]            
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.81% [2]   8.81% [2]   6.75% [1] 8.81% [2] 8.81% [2] 8.81% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 4.4 [3],[4]   $ 4.4 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.3 [3],[4]   $ 4.3 [3],[4]   $ 0.1 [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 8.70% [2]   8.70% [2]   6.75% [1] 8.70% [2] 8.70% [2] 8.70% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 10.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   10.7 [6],[7]            
Investment, Identifier [Axis]: Laboratories Bidco LLC and Laboratories Topco LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.00%   11.00%     11.00% 11.00% 11.00%      
Total first lien senior secured loans [3],[4] $ 3.9   $ 3.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 3.8   3.8                
Investment, Identifier [Axis]: Lakers Buyer, Inc. and Lakers Parent LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         11.1            
Less: funded commitments         (3.6)            
Total unfunded commitments         7.5            
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 commitments         7.5            
Investment, Identifier [Axis]: Lakers Buyer, Inc. and Lakers Parent LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         6.2            
Investment, Identifier [Axis]: Lakers Buyer, Inc. and Lakers Parent LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [6],[7]         51.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 51.2            
Investment, Identifier [Axis]: Lakers Buyer, Inc. and Lakers Parent LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7]         $ 3.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         3.6            
Investment, Identifier [Axis]: Lakers Buyer, Inc. and Lakers Parent LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [6],[7]         40.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         40.1            
Investment, Identifier [Axis]: Largest Portfolio Company Investment | Senior Direct Lending Program                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 380.0   380.0   $ 342.0            
Investment, Identifier [Axis]: LeanTaaS Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 55.3   55.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 55.3   55.3                
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 commitments $ 55.3   $ 55.3                
Investment, Identifier [Axis]: LeanTaas Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.05%   11.05%     11.05% 11.05% 11.05%      
Total first lien senior secured loans [3],[4] $ 30.5   $ 30.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 29.9   29.9                
Investment, Identifier [Axis]: Len the Plumber, LLC, LTP Neffsville, LLC, LTP of NJ, LLC, and LTP LSI, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 9.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         9.0            
Investment, Identifier [Axis]: Lew's Intermediate Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.3   2.3   2.3            
Less: funded commitments (1.3)   (1.3)   (1.8)            
Total unfunded commitments 1.0   1.0   0.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.0   $ 1.0   $ 0.5            
Investment, Identifier [Axis]: Lew's Intermediate Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.90% [2]   7.90% [2]   5.75% [1] 7.90% [2] 7.90% [2] 7.90% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 1.0 [3],[4]   $ 1.0 [3],[4]   $ 1.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.9 [3],[4]   $ 0.9 [3],[4]   $ 1.0 [6],[7]            
Investment, Identifier [Axis]: Lew's Intermediate Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.13% [2]   7.13% [2]   4.14% [1] 7.13% [2] 7.13% [2] 7.13% [2] 4.14% [1] 4.14% [1] 4.14% [1]
Total first lien senior secured loans $ 1.3 [4]   $ 1.3 [4]   $ 1.8 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.2 [4]   1.2 [4]   1.8 [7]            
Investment, Identifier [Axis]: Lido Advisors, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.8   0.8   0.8            
Less: funded commitments (0.2)   (0.2)   0.0            
Total unfunded commitments 0.6   0.6   0.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.6   $ 0.6   $ 0.8            
Investment, Identifier [Axis]: Lido Advisors, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.44%   7.44%     7.44% 7.44% 7.44%      
Total first lien senior secured loans [3] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] $ 0.2   $ 0.2                
Investment, Identifier [Axis]: Lifescan Global Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.29%   8.29%     8.29% 8.29% 8.29%      
Total first lien senior secured loans [4] $ 14.7   $ 14.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 12.3   $ 12.3                
Investment, Identifier [Axis]: Lifescan Global Corporation, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 11.79%   11.79%     11.79% 11.79% 11.79%      
Total first lien senior secured loans [4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 0.2   0.2                
Investment, Identifier [Axis]: Lower ACS, Inc. | Revolving and delayed draw loan commitments                      
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 commitments $ 25.9   $ 25.9                
Investment, Identifier [Axis]: Lower ACS, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.87%   8.87%     8.87% 8.87% 8.87%      
Total first lien senior secured loans [3],[4] $ 5.4   $ 5.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 5.4   $ 5.4                
Investment, Identifier [Axis]: MB Aerospace Holdings II Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.17% [2]   7.17% [2]   4.50% [1] 7.17% [2] 7.17% [2] 7.17% [2] 4.50% [1] 4.50% [1] 4.50% [1]
Total first lien senior secured loans $ 12.1 [3],[4]   $ 12.1 [3],[4]   $ 11.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 11.1 [3],[4]   $ 11.1 [3],[4]   $ 10.9 [6],[7]            
Investment, Identifier [Axis]: MB Aerospace Holdings II Corp., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.67% [2]   12.67% [2]   10.00% [1] 12.67% [2] 12.67% [2] 12.67% [2] 10.00% [1] 10.00% [1] 10.00% [1]
Total first lien senior secured loans $ 68.4 [3],[4]   $ 68.4 [3],[4]   $ 68.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 65.7 [3],[4]   $ 65.7 [3],[4]   $ 61.6 [6],[7]            
Investment, Identifier [Axis]: MB Aerospace Holdings II Corp., Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.67% [2]   12.67% [2]   10.00% [1] 12.67% [2] 12.67% [2] 12.67% [2] 10.00% [1] 10.00% [1] 10.00% [1]
Total first lien senior secured loans $ 23.6 [3],[4]   $ 23.6 [3],[4]   $ 23.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 22.7 [3],[4]   22.7 [3],[4]   21.3 [6],[7]            
Investment, Identifier [Axis]: MCH Holdings, Inc., MC Acquisition Holdings I, LLC and Privia Health Group, Inc., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 0.6            
Investment, Identifier [Axis]: MCH Holdings, Inc., MC Acquisition Holdings I, LLC and Privia Health Group, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 110.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         110.2            
Investment, Identifier [Axis]: ME Equity LLC, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.3 [4]   4.3 [4]   3.1 [7]            
Investment, Identifier [Axis]: MMIT Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.6   4.6   4.6            
Less: funded commitments (0.8)   (0.8)   (0.6)            
Total unfunded commitments 3.8   3.8   4.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.8   $ 3.8   $ 4.0            
Investment, Identifier [Axis]: MMIT Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.25%       7.25% 7.25% 7.25%
Total first lien senior secured loans [6],[7]         $ 18.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 18.0            
Investment, Identifier [Axis]: MMIT Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.92%   9.92%     9.92% 9.92% 9.92%      
Total first lien senior secured loans [3],[4] $ 13.6   $ 13.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 13.7   $ 13.7                
Investment, Identifier [Axis]: MMIT Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [2]   9.92% [2]   7.25% [1] 9.92% [2] 9.92% [2] 9.92% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 2.8 [3],[4]   $ 2.8 [3],[4]   $ 13.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.8 [3],[4]   $ 2.8 [3],[4]   $ 13.6 [6],[7]            
Investment, Identifier [Axis]: MMIT Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.50% [2]   9.50% [2]   7.25% [1] 9.50% [2] 9.50% [2] 9.50% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 0.8 [3]   $ 0.8 [3]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.8 [3]   0.8 [3]   0.6 [6],[7]            
Investment, Identifier [Axis]: MMax Investment Partners, Inc. (d/b/a Professional Fighters League) and PFL MMA, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]         15.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         13.9            
Investment, Identifier [Axis]: MMax Investment Partners, Inc. (d/b/a Professional Fighters League) and PFL MMA, Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         1.9            
Investment, Identifier [Axis]: MRI Software LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.7   12.7   10.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 12.7   12.7   10.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 12.7   $ 12.7   $ 10.2            
Investment, Identifier [Axis]: MRI Software LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6]         $ 51.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 51.5            
Investment, Identifier [Axis]: MRI Software LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.17%   9.17%     9.17% 9.17% 9.17%      
Total first lien senior secured loans [3] $ 47.2   $ 47.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] $ 45.8   $ 45.8                
Investment, Identifier [Axis]: MRI Software LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.50% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 15.4 [3],[4]   $ 15.4 [3],[4]   $ 4.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.9 [3],[4]   $ 14.9 [3],[4]   $ 4.5 [6],[7]            
Investment, Identifier [Axis]: Mac Lean-Fogg Company and MacLean-Fogg Holdings, L.L.C., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.87% [2]   7.87% [2]   5.88% [1] 7.87% [2] 7.87% [2] 7.87% [2] 5.88% [1] 5.88% [1] 5.88% [1]
Total first lien senior secured loans $ 84.9 [3],[4]   $ 84.9 [3],[4]   $ 123.8 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 84.9 [3],[4]   $ 84.9 [3],[4]   $ 123.8 [6]            
Investment, Identifier [Axis]: Mac Lean-Fogg Company and MacLean-Fogg Holdings, L.L.C., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.88%       5.88% 5.88% 5.88%
Total first lien senior secured loans [6],[7]         $ 19.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 19.1            
Investment, Identifier [Axis]: Mac Lean-Fogg Company and MacLean-Fogg Holdings, L.L.C., Preferred units                      
Schedule of Investments [Line Items]                      
Coupon | Rate 13.75% [2]   13.75% [2]   13.75% [1] 13.75% [2] 13.75% [2] 13.75% [2] 13.75% [1] 13.75% [1] 13.75% [1]
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 77.1 [4]   $ 77.1 [4]   $ 75.0            
Investment, Identifier [Axis]: Magnesium BorrowerCo, Inc. and Magnesium Co-Invest SCSp | Revolving and delayed draw loan commitments                      
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 commitments $ 15.1   $ 15.1                
Investment, Identifier [Axis]: Magnesium BorrowerCo, Inc. and Magnesium Co-Invest SCSp, 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 [3],[4],[5] $ 169.7   $ 169.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 166.3   166.3                
Investment, Identifier [Axis]: Magnesium BorrowerCo, Inc. and Magnesium Co-Invest SCSp, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 40.4   40.4                
Investment, Identifier [Axis]: MailSouth, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [4],[9] 8.8   8.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[9] 4.5   4.5                
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.0   2.0   2.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.0   2.0   2.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.0   2.0   2.0            
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.5 [4]   3.5 [4]   4.0 [7]            
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P., Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0   $ 0.0 [7]            
Investment, Identifier [Axis]: Majesco and Magic Topco, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.93% [2]   10.93% [2]   8.25% [1] 10.93% [2] 10.93% [2] 10.93% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 30.4 [3],[4]   $ 30.4 [3],[4]   $ 42.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 30.4 [3],[4]   30.4 [3],[4]   42.2 [6],[7]            
Investment, Identifier [Axis]: Management Consulting & Research LLC | Revolving and delayed draw loan commitments                      
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 commitments $ 4.0   $ 4.0                
Investment, Identifier [Axis]: Management Consulting & Research LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.73%   8.73%     8.73% 8.73% 8.73%      
Total first lien senior secured loans [3],[4] $ 1.0   $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.0   1.0                
Investment, Identifier [Axis]: Manna Pro Products, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.0   7.0   7.0            
Less: funded commitments (5.1)   (5.1)   (1.9)            
Total unfunded commitments 1.9   1.9   5.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.9   $ 1.9   $ 5.1            
Investment, Identifier [Axis]: Manna Pro Products, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.02% [2]   9.02% [2]   7.00% [1] 9.02% [2] 9.02% [2] 9.02% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 5.1 [3],[4]   $ 5.1 [3],[4]   $ 1.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.9 [3],[4]   4.9 [3],[4]   1.9 [6],[7]            
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC | Revolving and delayed draw loan commitments                      
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 commitments 1.2   1.2                
Investment, Identifier [Axis]: Marcone Yellowstone Buyer Inc. and Marcone Yellowstone Holdings, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 11.8 [4]   $ 11.8 [4]   $ 9.3 [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 9.08% [2]   9.08% [2]   6.25% [1] 9.08% [2] 9.08% [2] 9.08% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 30.9 [3],[4]   $ 30.9 [3],[4]   $ 18.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 30.5 [3],[4]   $ 30.5 [3],[4]   $ 18.5 [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 9.14% [2]   9.14% [2]   6.25% [1] 9.14% [2] 9.14% [2] 9.14% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 7.4 [3],[4]   $ 7.4 [3],[4]   $ 2.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.3 [3],[4]   7.3 [3],[4]   $ 2.1 [6]            
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 [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6]         $ 6.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 6.5            
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 [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[7]         $ 35.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 34.6            
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.0   7.0                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 7.0   7.0                
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 commitments $ 7.0   $ 7.0                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 34.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         34.4            
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.55%   9.55%     9.55% 9.55% 9.55%      
Total first lien senior secured loans [3],[4] $ 28.2   $ 28.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 27.9   $ 27.9                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.70%   9.70%     9.70% 9.70% 9.70%      
Total first lien senior secured loans [3],[4] $ 0.4   $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.4   $ 0.4                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.33%   8.33%     8.33% 8.33% 8.33%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
Investment, Identifier [Axis]: Marmic Purchaser, LLC and Marmic Topco, L.P., Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.5 [4]   2.5 [4]   2.4 [7]            
Investment, Identifier [Axis]: Maverick Acquisition, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 17.2   17.2   17.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 17.2   17.2   17.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 17.2   $ 17.2   $ 17.2            
Investment, Identifier [Axis]: Maverick Acquisition, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [2]   9.92% [2]   7.00% [1] 9.92% [2] 9.92% [2] 9.92% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 27.7 [3],[4]   $ 27.7 [3],[4]   $ 57.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 25.7 [3],[4]   25.7 [3],[4]   57.3 [6],[7]            
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]                      
Total investments at fair value [7]         $ 26.8            
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]         3.85%       3.85% 3.85% 3.85%
Total first lien senior secured loans [7],[14]         $ 15.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[14]         15.3            
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis HoldCo, Inc., and Metis TopCo, LP, Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         71.8            
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 32.9   32.9   32.9            
Less: funded commitments (7.3)   (7.3)   (23.4)            
Total unfunded commitments 25.6   25.6   9.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 25.6   25.6   9.5            
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]                      
Total investments at fair value [4] 37.1   37.1                
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP, First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [15] 0.0   0.0                
Investment, Identifier [Axis]: Mavis Tire Express Services Topco Corp., Metis Holdco, Inc. and Metis Topco, LP, Series A preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 75.6   75.6                
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5   4.5            
Less: funded commitments (1.9)   (1.9)   0.0            
Total unfunded commitments 2.6   2.6   4.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.6   $ 2.6   $ 4.5            
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.43% [2]   9.43% [2]   6.75% [1] 9.43% [2] 9.43% [2] 9.43% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 84.5 [3],[4],[20]   $ 84.5 [3],[4],[20]   $ 84.5 [6],[21]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 83.7 [3],[4],[20]   $ 83.7 [3],[4],[20]   $ 84.5 [6],[21]            
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.43% [2]   9.43% [2]   6.75% [1] 9.43% [2] 9.43% [2] 9.43% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 5.5 [3],[4]   $ 5.5 [3],[4]   $ 5.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.4 [3],[4]   $ 5.4 [3],[4]   $ 5.5 [6]            
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%
Total first lien senior secured loans $ 40.9   $ 40.9   $ 46.9            
Investment, Identifier [Axis]: McKenzie Creative Brands, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.79%   8.79%     8.79% 8.79% 8.79%      
Total first lien senior secured loans [3],[4] $ 1.9   $ 1.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.9   1.9                
Investment, Identifier [Axis]: McLaren Group Limited, Senior preference shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 25.0 [4],[5]   25.0 [4],[5]   27.1 [7],[8]            
Investment, Identifier [Axis]: McLaren Group Limited, Warrant to purchase ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         5.1            
Investment, Identifier [Axis]: McLaren Group Limited, Warrant to purchase ordinary shares 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         1.4            
Investment, Identifier [Axis]: McLaren Group Limited, Warrant to purchase up to 13,776 ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 0.9   0.9                
Investment, Identifier [Axis]: McLaren Group Limited, Warrant to purchase up to 49,181 ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 3.4   3.4                
Investment, Identifier [Axis]: Medline Borrower, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.9   6.9   6.9            
Less: funded commitments (0.2)   (0.2)   0.0            
Total unfunded commitments 6.7   6.7   6.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 6.7   6.7   6.9            
Investment, Identifier [Axis]: Medline Borrower, LP, First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: Miami Beckham United LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 92.7   92.7   87.1            
Investment, Identifier [Axis]: Micromeritics Instrument Corp. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1   4.1            
Less: funded commitments 0.0   0.0   (0.1)            
Total unfunded commitments 4.1   4.1   4.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.1   $ 4.1   $ 4.0            
Investment, Identifier [Axis]: Micromeritics Instrument Corp., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.38% [2]   7.38% [2]   6.00% [1] 7.38% [2] 7.38% [2] 7.38% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 24.0 [3],[4]   $ 24.0 [3],[4]   $ 32.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 24.0 [3],[4]   24.0 [3],[4]   $ 32.0 [6]            
Investment, Identifier [Axis]: Micromeritics Instrument Corp., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
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]                      
Total investments at fair value 6.1 [4]   6.1 [4]   4.5 [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]                      
Total first lien senior secured loans 153.5 [3]   153.5 [3]   153.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 153.5 [3]   153.5 [3]   150.4 [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]                      
Total investments at fair value 2.6 [4]   2.6 [4]   2.0 [7]            
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 31.3   31.3   31.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 31.3   31.3   31.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 31.3   $ 31.3   $ 31.3            
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 9.17% [2]   9.17% [2]   6.25% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 32.6 [3],[4]   $ 32.6 [3],[4]   $ 72.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 31.6 [3],[4]   31.6 [3],[4]   72.0 [6],[7]            
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P., First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [15] 0.0   0.0                
Investment, Identifier [Axis]: Ministry Brands Holdings, LLC and RCP MB Investments B, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 9.1 [4]   $ 9.1 [4]   9.6 [7]            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands) | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         10.9            
Less: funded commitments         (5.0)            
Total unfunded commitments         5.9            
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 commitments         5.9            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 7.2            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.00%       5.00% 5.00% 5.00%
Total first lien senior secured loans [6]         $ 9.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 9.2            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.00%       5.00% 5.00% 5.00%
Total first lien senior secured loans [6]         $ 4.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 4.7            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.25%       7.25% 7.25% 7.25%
Total first lien senior secured loans [6]         $ 5.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 5.0            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.25%       10.25% 10.25% 10.25%
Total first lien senior secured loans [6]         $ 106.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 106.6            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.25%       10.25% 10.25% 10.25%
Total first lien senior secured loans [6],[7]         $ 13.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 13.9            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), Second lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.25%       10.25% 10.25% 10.25%
Total first lien senior secured loans [6],[7]         $ 17.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 17.9            
Investment, Identifier [Axis]: Ministry Brands, LLC and MB Parent HoldCo, L.P. (dba Community Brands), Second lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.00%       9.00% 9.00% 9.00%
Total first lien senior secured loans [6],[7]         $ 48.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 48.9            
Investment, Identifier [Axis]: Mitchell International, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.57% [2]   9.57% [2]   7.00% [1] 9.57% [2] 9.57% [2] 9.57% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 91.2 [3],[4],[11]   $ 91.2 [3],[4],[11]   $ 91.2 [6],[7],[12]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 85.2 [3],[4],[11]   85.2 [3],[4],[11]   91.6 [6],[7],[12]            
Investment, Identifier [Axis]: Monica Holdco (US) Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.6   3.6   3.6            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.6   3.6   3.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.6   $ 3.6   $ 3.6            
Investment, Identifier [Axis]: Monica Holdco (US) Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [2]   9.92% [2]   7.25% [1] 9.92% [2] 9.92% [2] 9.92% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 2.6 [3],[4]   $ 2.6 [3],[4]   $ 2.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.6 [3],[4]   2.6 [3],[4]   $ 2.6 [6],[7]            
Investment, Identifier [Axis]: Monica Holdco (US) Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Monolith Brands Group, Inc., Series A-1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 15.5   15.5                
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 | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.2   15.2   15.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 15.2   15.2   15.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 15.2   $ 15.2   $ 15.2            
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, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.87% [2]   8.87% [2]   6.75% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 77.4 [3],[4]   $ 77.4 [3],[4]   $ 79.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 77.4 [3],[4]   77.4 [3],[4]   78.2 [6]            
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]                      
Total investments at fair value 24.0   24.0   $ 96.9            
Investment, Identifier [Axis]: Moonraker AcquisitionCo LLC and Moonraker HoldCo LLC | Revolving and delayed draw loan commitments                      
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 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]                      
Total investments at 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 [2] 9.03%   9.03%     9.03% 9.03% 9.03%      
Total first lien senior secured loans [3],[4] $ 26.7   $ 26.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 26.2   $ 26.2                
Investment, Identifier [Axis]: Movati Athletic (Group) Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.76% [2]   8.76% [2]   7.45% [1] 8.76% [2] 8.76% [2] 8.76% [2] 7.45% [1] 7.45% [1] 7.45% [1]
Total first lien senior secured loans $ 4.6 [3],[4],[5]   $ 4.6 [3],[4],[5]   $ 0.2 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.5 [3],[4],[5]   4.5 [3],[4],[5]   $ 0.2 [6],[7],[8]            
Investment, Identifier [Axis]: Movati Athletic (Group) Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7],[8]         $ 2.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 2.7            
Investment, Identifier [Axis]: Movati Athletic (Group) Inc., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[8]         $ 2.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[8]         $ 2.1            
Investment, Identifier [Axis]: Murchison Oil and Gas, LLC and Murchison Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 27.5   27.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 27.5   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 commitments $ 27.5   $ 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 12.20% [2]   12.20% [2]   11.00% [1] 12.20% [2] 12.20% [2] 12.20% [2] 11.00% [1] 11.00% [1] 11.00% [1]
Total first lien senior secured loans $ 75.5 [3],[4]   $ 75.5 [3],[4]   $ 2.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 75.5 [3],[4]   75.5 [3],[4]   $ 2.7 [6],[7]            
Investment, Identifier [Axis]: Murchison Oil and Gas, LLC and Murchison Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.00%       10.00% 10.00% 10.00%
Total first lien senior secured loans [6],[7]         $ 38.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 38.3            
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%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 45.1   45.1   $ 27.4            
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.0   3.0   3.0            
Less: funded commitments (0.6)   (0.6)   (0.6)            
Total unfunded commitments 2.4   2.4   2.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.4   $ 2.4   $ 2.4            
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.50%       7.50% 7.50% 7.50%
Total first lien senior secured loans [6],[7]         $ 2.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 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 [2] 10.20%   10.20%     10.20% 10.20% 10.20%      
Total first lien senior secured loans [3],[4] $ 6.3   $ 6.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 6.3   $ 6.3                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.20% [2]   10.20% [2]   7.00% [1] 10.20% [2] 10.20% [2] 10.20% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 2.3 [3],[4]   $ 2.3 [3],[4]   $ 6.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.3 [3],[4]   $ 2.3 [3],[4]   $ 6.4 [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 [2] 10.20%   10.20%     10.20% 10.20% 10.20%      
Total first lien senior secured loans [3],[4] $ 1.3   $ 1.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.3   $ 1.3                
Investment, Identifier [Axis]: NAS, LLC and Nationwide Marketing Group, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.53% [2]   9.53% [2]   8.75% [1] 9.53% [2] 9.53% [2] 9.53% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 0.6 [3],[4]   $ 0.6 [3],[4]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.6 [3],[4]   0.6 [3],[4]   0.6 [6],[7]            
Investment, Identifier [Axis]: NCWS Intermediate, Inc. and NCWS Holdings LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.3   28.3   28.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 28.3   28.3   28.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 28.3   28.3   28.3            
Investment, Identifier [Axis]: NCWS Intermediate, Inc. and NCWS Holdings LP, Class A-2 common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 17.5 [4]   $ 17.5 [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 9.12% [2]   9.12% [2]   6.75% [1] 9.12% [2] 9.12% [2] 9.12% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 147.2 [3],[4]   $ 147.2 [3],[4]   $ 12.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 145.8 [3],[4]   $ 145.8 [3],[4]   $ 12.0 [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 9.12% [2]   9.12% [2]   6.75% [1] 9.12% [2] 9.12% [2] 9.12% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 176.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [3],[4]   0.2 [3],[4]   174.7 [6],[7]            
Investment, Identifier [Axis]: NECCO Holdings, Inc. and New England Confectionery Company, Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         1.9            
Redemptions (cost)         14.5            
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):         (12.4)            
Net unrealized gains (losses):         8.0            
Total investments at fair value         0.0            
Investment, Identifier [Axis]: NECCO Realty Investments LLC                      
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):         0.0            
Total investments at fair value         $ 0.0            
Investment, Identifier [Axis]: NM GRC Holdco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 45.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         45.4            
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.7   12.7   9.1            
Less: funded commitments 0.0   0.0   (6.2)            
Total unfunded commitments 12.7   12.7   2.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 12.7   $ 12.7   $ 2.9            
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.81% [2]   7.81% [2]   6.00% [1] 7.81% [2] 7.81% [2] 7.81% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 32.0 [3],[4]   $ 32.0 [3],[4]   $ 24.2 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 31.1 [3],[4]   $ 31.1 [3],[4]   $ 23.9 [6]            
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.07% [2]   7.07% [2]   6.00% [1] 7.07% [2] 7.07% [2] 7.07% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 4.7 [3],[4]   $ 4.7 [3],[4]   $ 8.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.6 [3],[4]   4.6 [3],[4]   $ 8.1 [6]            
Investment, Identifier [Axis]: NMC Skincare Intermediate Holdings II, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6],[7]         $ 6.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         6.1            
Investment, Identifier [Axis]: NMN Holdings III Corp. and NMN Holdings LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.5   12.5   12.5            
Less: funded commitments (2.8)   (2.8)   (1.1)            
Total unfunded commitments 9.7   9.7   11.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.7   $ 9.7   $ 11.4            
Investment, Identifier [Axis]: NMN Holdings III Corp. and NMN Holdings LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.00% [2]   9.00% [2]   0.00% [1] 9.00% [2] 9.00% [2] 9.00% [2] 0.00% [1] 0.00% [1] 0.00% [1]
Total first lien senior secured loans [4],[13] $ 2.0   $ 2.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.9 [4],[13]   1.9 [4],[13]   $ 0.0 [16]            
Investment, Identifier [Axis]: NMN Holdings III Corp. and NMN Holdings LP, Partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.5 [4]   2.5 [4]   2.8 [7]            
Investment, Identifier [Axis]: NSM Insurance Group, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         6.0            
Less: funded commitments         (0.7)            
Total unfunded commitments         5.3            
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 commitments         $ 5.3            
Investment, Identifier [Axis]: NSM Insurance Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6]         $ 12.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 12.8            
Investment, Identifier [Axis]: NSM Insurance Group, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7],[14]         $ 0.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[14]         0.5            
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.4 [4]   4.4 [4]   4.1 [7]            
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [4]   0.2 [4]   $ 0.1 [7]            
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         11.00%       11.00% 11.00% 11.00%
Total first lien senior secured loans [6],[7]         $ 72.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         72.8            
Investment, Identifier [Axis]: Napa Management Services Corporation and ASP NAPA Holdings, LLC, Senior preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.3 [4]   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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value [4] 40.9   40.9                
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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: National Intergovernmental Purchasing Alliance Company | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.0   9.0   9.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 9.0   9.0   9.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.0   $ 9.0   9.0            
Investment, Identifier [Axis]: National Spine and Pain Centers, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.31%   7.31%     7.31% 7.31% 7.31%      
Total first lien senior secured loans [3],[4] $ 0.0   $ 0.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.0   0.0                
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0   6.6            
Redemptions (cost)     131.0   0.0            
Sales (cost)     0.0   0.0            
Interest income     0.4   8.9            
Capital structuring service fees     0.0   0.1            
Dividend income     0.1   0.4            
Other income     0.0   0.1            
Net realized gains (losses):     19.0   0.0            
Net unrealized gains (losses):     (10.8)   12.6            
Total investments at fair value 0.0   0.0   143.7            
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         11.8            
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]         54.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         54.4            
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7]         15.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 15.2            
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.00%       8.00% 8.00% 8.00%
Total first lien senior secured loans [7]         $ 46.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         46.5            
Investment, Identifier [Axis]: Navisun LLC and Navisun Holdings LLC, Series A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         15.8            
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   0.6   0.6            
Less: funded commitments (0.1)   (0.1)   (0.2)            
Total unfunded commitments 0.5   0.5   0.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.5   0.5   0.4            
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]                      
Total investments at fair value [4],[5] $ 7.6   $ 7.6                
Investment, Identifier [Axis]: Nelipak Holding Company, Nelipak European Holdings Cooperatief U.A., KNPAK Holdings, LP and PAKNK Netherlands Treasury B.V., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[8]         $ 7.1            
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 4.50% [2]   4.50% [2]   5.25% [1] 4.50% [2] 4.50% [2] 4.50% [2] 5.25% [1] 5.25% [1] 5.25% [1]
Total first lien senior secured loans $ 4.4 [4],[5]   $ 4.4 [4],[5]   $ 15.0 [6],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.3 [4],[5]   $ 4.3 [4],[5]   $ 15.0 [6],[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 7.37% [2]   7.37% [2]   4.50% [1] 7.37% [2] 7.37% [2] 7.37% [2] 4.50% [1] 4.50% [1] 4.50% [1]
Total first lien senior secured loans $ 14.9 [3],[4],[5]   $ 14.9 [3],[4],[5]   $ 5.2 [7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.6 [3],[4],[5]   $ 14.6 [3],[4],[5]   $ 5.2 [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 4.50% [2]   4.50% [2]   4.50% [1] 4.50% [2] 4.50% [2] 4.50% [2] 4.50% [1] 4.50% [1] 4.50% [1]
Total first lien senior secured loans $ 1.4 [4],[5]   $ 1.4 [4],[5]   $ 24.4 [7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.4 [4],[5]   $ 1.4 [4],[5]   $ 24.4 [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 7.33% [2]   7.33% [2]   5.25% [1] 7.33% [2] 7.33% [2] 7.33% [2] 5.25% [1] 5.25% [1] 5.25% [1]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [3],[4],[5]   $ 0.2 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4],[5]   0.1 [3],[4],[5]   0.2 [6],[7],[8]            
Investment, Identifier [Axis]: Nest Topco Borrower Inc., KKR Nest Co-Invest L.P., and NBLY 2021-1 | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 119.1   119.1   119.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 119.1   119.1   119.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 119.1   119.1   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]                      
Total investments at fair value $ 9.5 [4]   $ 9.5 [4]   $ 9.7 [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 11.58% [2]   11.58% [2]   9.00% [1] 11.58% [2] 11.58% [2] 11.58% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 119.1 [3],[4]   $ 119.1 [3],[4]   $ 119.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 117.9 [3],[4]   $ 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 [2] 8.46%   8.46%     8.46% 8.46% 8.46%      
Total first lien senior secured loans [3],[4] $ 28.1   $ 28.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 28.1   28.1                
Investment, Identifier [Axis]: Noble Aerospace, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.6   5.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.6   5.6                
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 commitments 5.6   5.6                
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.1   8.1   23.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 8.1   8.1   23.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 8.1   8.1   23.9            
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.7 [4]   $ 2.7 [4]   $ 1.2 [7]            
Investment, Identifier [Axis]: North American Fire Holdings, LLC and North American Fire Ultimate Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 20.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         20.1            
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 [2] 9.45%   9.45%     9.45% 9.45% 9.45%      
Total first lien senior secured loans [3],[4] $ 20.0   $ 20.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 20.0   $ 20.0                
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 [2] 8.91%   8.91%     8.91% 8.91% 8.91%      
Total first lien senior secured loans [3],[4] $ 2.9   $ 2.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 2.9   2.9                
Investment, Identifier [Axis]: North American Science Associates, LLC, Cardinal Purchaser LLC and Cardinal Topco Holdings, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         6.0            
Less: funded commitments         0.0            
Total unfunded commitments         6.0            
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 commitments         6.0            
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]                      
Total investments at fair value $ 35.9 [4]   $ 35.9 [4]   $ 32.8 [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 9.11% [2]   9.11% [2]   6.50% [1] 9.11% [2] 9.11% [2] 9.11% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 47.7 [3],[4]   $ 47.7 [3],[4]   $ 48.0 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 47.7 [3],[4]   $ 47.7 [3],[4]   $ 48.0 [6]            
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 9.11% [2]   9.11% [2]   6.50% [1] 9.11% [2] 9.11% [2] 9.11% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 2.5 [3],[4]   $ 2.5 [3],[4]   $ 2.6 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.5 [3],[4]   $ 2.5 [3],[4]   $ 2.6 [6]            
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 9.11% [2]   9.11% [2]   6.50% [1] 9.11% [2] 9.11% [2] 9.11% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 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 [2] 9.11%   9.11%     9.11% 9.11% 9.11%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: North Haven Falcon Buyer, LLC and North Haven Falcon Holding Company, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.5   3.5   6.7            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.5   3.5   6.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 3.5   3.5   6.7            
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]                      
Total investments at fair value $ 3.0   $ 3.0   $ 4.1            
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 | Rate 8.01% [2]   8.01% [2]   7.00% [1] 8.01% [2] 8.01% [2] 8.01% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 21.7 [3],[4]   $ 21.7 [3],[4]   $ 22.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 20.9 [3],[4]   $ 20.9 [3],[4]   22.1 [6],[7]            
Investment, Identifier [Axis]: North Haven Falcon Buyer, LLC and North Haven Falcon Holding Company, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.67%   8.67%     8.67% 8.67% 8.67%      
Total first lien senior secured loans [3],[4] $ 3.6   $ 3.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 3.5   3.5                
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.5   5.5   10.0            
Less: funded commitments (0.6)   (0.6)   0.0            
Total unfunded commitments 4.9   4.9   10.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.9   $ 4.9   $ 10.0            
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.63% [2]   8.63% [2]   6.50% [1] 8.63% [2] 8.63% [2] 8.63% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 4.8 [3],[4]   $ 4.8 [3],[4]   $ 11.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.6 [3],[4]   $ 4.6 [3],[4]   11.0 [6],[7]            
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.63%   8.63%     8.63% 8.63% 8.63%      
Total first lien senior secured loans [3],[4] $ 1.7   $ 1.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.7   $ 1.7                
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.96%   7.96%     7.96% 7.96% 7.96%      
Total first lien senior secured loans [3],[4] $ 0.4   $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.4   $ 0.4                
Investment, Identifier [Axis]: North Haven Stack Buyer, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.75%   10.75%     10.75% 10.75% 10.75%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
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]                      
Total investments at fair value 9.9 [4]   9.9 [4]   6.3 [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]                      
Total investments at fair value $ 0.0   $ 0.0   $ 0.0 [7]            
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 8.37% [2]   8.37% [2]   6.75% [1] 8.37% [2] 8.37% [2] 8.37% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 23.5 [3],[4]   $ 23.5 [3],[4]   $ 23.9 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 23.5 [3],[4]   $ 23.5 [3],[4]   23.9 [6]            
Investment, Identifier [Axis]: NueHealth Performance, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         6.2            
Less: funded commitments         (3.3)            
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 commitments         $ 2.9            
Investment, Identifier [Axis]: NueHealth Performance, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.25%       8.25% 8.25% 8.25%
Total first lien senior secured loans [6]         $ 12.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 12.4            
Investment, Identifier [Axis]: NueHealth Performance, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.25%       8.25% 8.25% 8.25%
Total first lien senior secured loans [6],[7]         $ 3.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 3.0            
Investment, Identifier [Axis]: NueHealth Performance, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.25%       8.25% 8.25% 8.25%
Total first lien senior secured loans [6],[7]         $ 3.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 3.3            
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.02% [2]   10.02% [2]   6.50% [1] 10.02% [2] 10.02% [2] 10.02% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 25.9 [3],[4]   $ 25.9 [3],[4]   $ 26.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 25.9 [3],[4]   $ 25.9 [3],[4]   $ 26.1 [6]            
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.02% [2]   10.02% [2]   6.50% [1] 10.02% [2] 10.02% [2] 10.02% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 15.3 [3],[4]   $ 15.3 [3],[4]   $ 15.4 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 15.3 [3],[4]   $ 15.3 [3],[4]   15.4 [6]            
Investment, Identifier [Axis]: OMH-HealthEdge Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.42%   9.42%     9.42% 9.42% 9.42%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: OTG Management, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.1 [4]   13.1 [4]   15.8            
Investment, Identifier [Axis]: OTG Management, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: OTG Management, LLC, Warrant to purchase common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 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]                      
Total investments at 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% [2]   7.00% [2]   7.00% [1] 7.00% [2] 7.00% [2] 7.00% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 32.6 [4],[5]   $ 32.6 [4],[5]   $ 44.4 [7],[8]            
Investment, Identifier [Axis]: Offen, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.6   5.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 5.6   5.6                
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 commitments $ 5.6   $ 5.6                
Investment, Identifier [Axis]: Offen, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.50%   8.50%     8.50% 8.50% 8.50%      
Total first lien senior secured loans [4] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 1.4   1.4                
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         11.0            
Less: funded commitments         (10.3)            
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 commitments         0.7            
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P., Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 0.0            
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 42.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 34.5            
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 0.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 0.8            
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7]         $ 10.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 8.3            
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7]         $ 0.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         0.2            
Investment, Identifier [Axis]: Olympia Acquisition, Inc. and Olympia TopCo, L.P., Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.3            
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P. and Asclepius Hodlings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     3.3                
Redemptions (cost)     0.0                
Sales (cost)     0.0                
Interest income     3.2                
Capital structuring service fees     0.1                
Dividend income     0.0                
Other income     0.1                
Net realized gains (losses):     0.0                
Net unrealized gains (losses):     (3.4)                
Total investments at fair value 48.6   48.6                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.6   6.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 6.6   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 commitments 6.6   6.6                
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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   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 [3] 49.3   49.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 45.3   45.3                
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 [3],[4] 3.5   3.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 3.3   3.3                
Investment, Identifier [Axis]: Olympia Acquisition, Inc., Olympia TopCo, L.P., and Asclepius Holdings LLC, Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: OneDigital Borrower LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5   7.5            
Less: funded commitments (0.4)   (0.4)   0.0            
Total unfunded commitments 7.1   7.1   7.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 7.1   7.1   $ 7.5            
Investment, Identifier [Axis]: OneDigital Borrower LLC, First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [15] 0.0   0.0                
Investment, Identifier [Axis]: OneDigital Holdings, Achilles Holdco, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [16]         $ 0.0            
Investment, Identifier [Axis]: Opal Fuels LLC and Opal Fuels Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [5],[11] 25.3   25.3                
Investment, Identifier [Axis]: Opal Fuels LLC and Opal Fuels Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [5] 28.0   28.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [5] $ 28.0   $ 28.0                
Investment, Identifier [Axis]: Opal Fuels LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans         52.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 47.8            
Investment, Identifier [Axis]: OpenMarket Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [2]   9.92% [2]   7.00% [1] 9.92% [2] 9.92% [2] 9.92% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 51.7 [3],[4],[5]   $ 51.7 [3],[4],[5]   $ 50.7 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 51.2 [3],[4],[5]   $ 51.2 [3],[4],[5]   $ 50.1 [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 9.87% [2]   9.87% [2]   7.25% [1] 9.87% [2] 9.87% [2] 9.87% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 55.3 [3],[4]   $ 55.3 [3],[4]   $ 55.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 51.9 [3],[4]   51.9 [3],[4]   54.7 [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):     4.2   0.8            
Total investments at fair value 15.3   15.3   11.1            
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment II, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 15.3 [4],[5]   15.3 [4],[5]   11.1 [7],[8],[19]            
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   0.6            
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):     (0.6)   1.5            
Total investments at fair value 0.7   0.7   1.3            
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment, L.P. and PCG-Ares Sidecar Investment II, L.P. | Private equity commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 50.0   50.0   50.0            
Less: funded commitments (12.5)   (12.5)   (12.5)            
Total unfunded commitments 37.5   37.5   37.5            
Less: commitments substantially at discretion of the Company (37.5)   (37.5)   (37.5)            
Total net adjusted unfunded revolving and delayed draw commitments 0.0   0.0   0.0            
Investment, Identifier [Axis]: PCG-Ares Sidecar Investment, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.7 [5]   0.7 [5]   1.3 [8],[19]            
Investment, Identifier [Axis]: PDDS HoldCo, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.6   2.6                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.6   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 commitments $ 2.6   $ 2.6                
Investment, Identifier [Axis]: PDDS Holdco, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.89%   9.89%     9.89% 9.89% 9.89%      
Total first lien senior secured loans [3],[4] $ 9.0   $ 9.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 8.8   8.8                
Investment, Identifier [Axis]: PDI TA Hholdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [6],[7]         70.1            
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.6   7.6   7.6            
Less: funded commitments (4.7)   (4.7)   0.0            
Total unfunded commitments 2.9   2.9   7.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.9   2.9   7.6            
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]                      
Total investments at fair value $ 2.8 [4]   $ 2.8 [4]   $ 2.9 [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 7.16% [2]   7.16% [2]   5.50% [1] 7.16% [2] 7.16% [2] 7.16% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 53.1 [3],[4]   $ 53.1 [3],[4]   $ 53.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 52.0 [3],[4]   $ 52.0 [3],[4]   $ 53.5 [6]            
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 [2] 7.21%   7.21%     7.21% 7.21% 7.21%      
Total first lien senior secured loans [3],[4] $ 4.7   $ 4.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 4.6   $ 4.6                
Investment, Identifier [Axis]: PDI TA Holdings, Inc., Peachtree Parent, Inc. and Insight PDI Holdings, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.50%       9.50% 9.50% 9.50%
Total first lien senior secured loans [6],[7]         $ 7.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 7.2            
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 [2] 11.49%   11.49%     11.49% 11.49% 11.49%      
Total first lien senior secured loans [3],[4] $ 70.2   $ 70.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 69.5   $ 69.5                
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 11.49% [2]   11.49% [2]   9.50% [1] 11.49% [2] 11.49% [2] 11.49% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans [3],[4] $ 8.7   $ 8.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.7 [3],[4]   $ 8.7 [3],[4]   $ 70.1 [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 11.49% [2]   11.49% [2]   9.50% [1] 11.49% [2] 11.49% [2] 11.49% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 8.3 [3],[4]   $ 8.3 [3],[4]   $ 8.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.2 [3],[4]   $ 8.2 [3],[4]   $ 8.3 [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 11.49% [2]   11.49% [2]   9.50% [1] 11.49% [2] 11.49% [2] 11.49% [2] 9.50% [1] 9.50% [1] 9.50% [1]
Total first lien senior secured loans $ 7.2 [3],[4]   $ 7.2 [3],[4]   $ 8.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 7.1 [3],[4]   7.1 [3],[4]   8.7 [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]                      
Total investments at fair value 21.1 [4]   21.1 [4]   19.7 [7]            
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC (fka QC Supply, LLC), Common unit                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 7.4            
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC (fka QC Supply, LLC), First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 14.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 14.9            
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC (fka QC Supply, LLC), First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 2.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         2.8            
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC, Common unit                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 6.2   $ 6.2                
Investment, Identifier [Axis]: PS Operating Company LLC and PS OP Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.67%   9.67%     9.67% 9.67% 9.67%      
Total first lien senior secured loans [3],[4] $ 14.9   $ 14.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 14.9   $ 14.9                
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 [2] 9.67%   9.67%     9.67% 9.67% 9.67%      
Total first lien senior secured loans [3],[4] $ 4.3   $ 4.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 4.3   4.3                
Investment, Identifier [Axis]: PS Operating Company LLC and PS Op Holdings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     4.3   3.9            
Redemptions (cost)     2.7   1.2            
Sales (cost)     0.0   0.0            
Interest income     1.0   0.0            
Capital structuring service fees     0.0   0.0            
Dividend income     0.0   0.0            
Other income     0.1   0.0            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     (1.2)   0.0            
Total investments at fair value 25.4   25.4   25.1            
Investment, Identifier [Axis]: PS Operating Company LLC and PS Op Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.9   5.9   5.9            
Less: funded commitments (4.3)   (4.3)   (2.8)            
Total unfunded commitments 1.6   1.6   3.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 1.6   1.6   3.1            
Investment, Identifier [Axis]: Padres L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 64.2   64.2   64.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 64.2   64.2   64.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 64.2   $ 64.2   $ 64.2            
Investment, Identifier [Axis]: Padres L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.06% [2]   8.06% [2]   6.00% [1] 8.06% [2] 8.06% [2] 8.06% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 92.8 [3],[4]   $ 92.8 [3],[4]   $ 92.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 92.8 [3],[4]   92.8 [3],[4]   92.8 [6],[7]            
Investment, Identifier [Axis]: Panda Temple Power, LLC and T1 Power Holdings LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         0.0            
Redemptions (cost)         19.6            
Sales (cost)         0.0            
Interest income         0.2            
Capital structuring service fees         0.0            
Dividend income         0.0            
Other income         0.0            
Net realized gains (losses):         9.8            
Net unrealized gains (losses):         0.9            
Total investments at fair value         0.0            
Investment, Identifier [Axis]: Partnership Capital Growth Investors III, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.9 [4],[5],[11]   3.9 [4],[5],[11]   3.6 [8],[12]            
Investment, Identifier [Axis]: Pathway Vet Alliance LLC and Jedi Group Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9   1.9   1.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 1.9   1.9   1.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 1.9   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]                      
Total investments at fair value 6.5 [4]   6.5 [4]   $ 7.9 [7]            
Investment, Identifier [Axis]: Pathway Vet Alliance LLC and Jedi Group Holdings LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [15]   $ 0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Pathway Vet Alliance LLC and Jedi Group Holdings LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.87% [2]   10.87% [2]   8.75% [1] 10.87% [2] 10.87% [2] 10.87% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 76.3 [3],[4]   $ 76.3 [3],[4]   $ 76.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 72.5 [3],[4]   72.5 [3],[4]   76.3 [6],[7]            
Investment, Identifier [Axis]: Patriot Growth Insurance Services, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.6   3.6   6.7            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.6   3.6   6.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.6   $ 3.6   $ 6.7            
Investment, Identifier [Axis]: Patriot Growth Insurance Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.65% [2]   8.65% [2]   6.25% [1] 8.65% [2] 8.65% [2] 8.65% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 13.7 [3],[4]   $ 13.7 [3],[4]   $ 11.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 13.3 [3],[4]   $ 13.3 [3],[4]   11.5 [6],[7]            
Investment, Identifier [Axis]: Patriot Growth Insurance Services, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.31%   9.31%     9.31% 9.31% 9.31%      
Total first lien senior secured loans [3] $ 0.9   $ 0.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 0.9   0.9                
Investment, Identifier [Axis]: PayNearMe, Inc., Warrant to purchase shares of Series E preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: Paya, Inc and GTCR-Ultra Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.5   4.5   4.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.5   4.5   4.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 4.5   4.5   4.5            
Investment, Identifier [Axis]: Paya, Inc and GTCR-Ultra Holdings LLC, Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.0 [4]   2.0 [4]   2.1 [7]            
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 34.0   34.0   45.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 34.0   34.0   45.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 34.0   34.0   45.9            
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]                      
Total investments at fair value 15.1   15.1   $ 12.3            
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.25%       6.25% 6.25% 6.25%
Total first lien senior secured loans [6],[7]         $ 0.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.2            
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]                      
Total first lien senior secured loans [3],[4] 13.7   13.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 13.7   $ 13.7                
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 9.42% [2]   9.42% [2]   6.75% [1] 9.42% [2] 9.42% [2] 9.42% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 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 8.92% [2]   8.92% [2]   6.75% [1] 8.92% [2] 8.92% [2] 8.92% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 29.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.2 [3],[4]   $ 0.2 [3],[4]   29.9 [6],[7]            
Investment, Identifier [Axis]: Pegasus Global Enterprise Holdings, LLC, Mekone Blocker Acquisition, Inc. and Mekone Parent, LLC,h First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.42%   9.42%     9.42% 9.42% 9.42%      
Investment, Identifier [Axis]: Pelican Products, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments $ 2.3   $ 2.3   2.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.3   2.3   2.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.3   $ 2.3   $ 2.3            
Investment, Identifier [Axis]: Pelican Products, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.92% [2]   11.92% [2]   8.25% [1] 11.92% [2] 11.92% [2] 11.92% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 60.0 [3],[4]   $ 60.0 [3],[4]   $ 60.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 56.4 [3],[4]   56.4 [3],[4]   59.4 [6],[7]            
Investment, Identifier [Axis]: People Corporation | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 21.9   21.9   29.4            
Less: funded commitments (5.1)   (5.1)   (2.9)            
Total unfunded commitments 16.8   16.8   26.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 16.8   $ 16.8   $ 26.5            
Investment, Identifier [Axis]: People Corporation, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.87% [2]   9.87% [2]   6.25% [1] 9.87% [2] 9.87% [2] 9.87% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 40.2 [3],[4],[5]   $ 40.2 [3],[4],[5]   $ 1.4 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 39.8 [3],[4],[5]   $ 39.8 [3],[4],[5]   $ 1.4 [6],[7],[8]            
Investment, Identifier [Axis]: People Corporation, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.87% [2]   9.87% [2]   7.25% [1] 9.87% [2] 9.87% [2] 9.87% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 12.6 [3],[4],[5]   $ 12.6 [3],[4],[5]   $ 44.3 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 12.4 [3],[4],[5]   $ 12.4 [3],[4],[5]   $ 44.3 [6],[7],[8]            
Investment, Identifier [Axis]: People Corporation, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.13% [2]   9.13% [2]   7.25% [1] 9.13% [2] 9.13% [2] 9.13% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 6.2 [3],[4],[5]   $ 6.2 [3],[4],[5]   $ 13.8 [6],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.0 [3],[4],[5]   $ 6.0 [3],[4],[5]   $ 13.8 [6],[8]            
Investment, Identifier [Axis]: People Corporation, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.92% [2]   9.92% [2]   7.25% [1] 9.92% [2] 9.92% [2] 9.92% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 5.1 [3],[4],[5]   $ 5.1 [3],[4],[5]   $ 2.9 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 5.1 [3],[4],[5]   5.1 [3],[4],[5]   2.9 [6],[7],[8]            
Investment, Identifier [Axis]: Perforce Software, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.5   0.5   0.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.5   0.5   0.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 0.5   0.5   0.5            
Investment, Identifier [Axis]: Perforce Software, Inc., First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: PetVet Care Centers, LLC, First lien senior secured 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 [3],[4] $ 5.3   $ 5.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 5.3   5.3                
Investment, Identifier [Axis]: Petroleum Service Group LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 17.6   17.6   16.9            
Less: funded commitments (3.2)   (3.2)   (3.8)            
Total unfunded commitments 14.4   14.4   13.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 14.4   $ 14.4   $ 13.1            
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.82% [2]   8.82% [2]   7.00% [1] 8.82% [2] 8.82% [2] 8.82% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 34.6 [3],[4]   $ 34.6 [3],[4]   $ 8.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 34.6 [3],[4]   $ 34.6 [3],[4]   $ 8.1 [6],[7]            
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.14% [2]   9.14% [2]   1.00% [1] 9.14% [2] 9.14% [2] 9.14% [2] 1.00% [1] 1.00% [1] 1.00% [1]
Total first lien senior secured loans $ 8.0 [3],[4]   $ 8.0 [3],[4]   $ 0.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.0 [3],[4]   $ 8.0 [3],[4]   $ 0.2 [6],[7]            
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.50% [2]   9.50% [2]   7.00% [1] 9.50% [2] 9.50% [2] 9.50% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 3.5 [3],[4]   $ 3.5 [3],[4]   $ 34.2 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.5 [3],[4]   $ 3.5 [3],[4]   $ 34.2 [6]            
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 0.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.7            
Investment, Identifier [Axis]: Petroleum Service Group LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.76% [2]   8.76% [2]   7.00% [1] 8.76% [2] 8.76% [2] 8.76% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 1.8 [3],[4],[13]   $ 1.8 [3],[4],[13]   $ 2.2 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [3],[4],[13]   1.8 [3],[4],[13]   $ 2.2 [6],[7],[14]            
Investment, Identifier [Axis]: Petvisor Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 40.1   40.1                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 40.1   40.1                
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 commitments $ 40.1   $ 40.1                
Investment, Identifier [Axis]: Petvisor Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.43%   7.43%     7.43% 7.43% 7.43%      
Total first lien senior secured loans [3],[4] $ 19.0   $ 19.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 18.6   18.6                
Investment, Identifier [Axis]: PhyMED Management LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         15.00%       15.00% 15.00% 15.00%
Total first lien senior secured loans [6],[7]         $ 55.7            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         52.4            
Investment, Identifier [Axis]: Piper Jaffray Merchant Banking Fund I, L.P., Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.5 [5],[11]   0.5 [5],[11]   1.0 [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]                      
Total investments at fair value $ 0.6 [4]   $ 0.6 [4]   $ 0.9 [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 [2] 6.81%   6.81%     6.81% 6.81% 6.81%      
Total first lien senior secured loans [3],[4] $ 22.7   $ 22.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 21.3   $ 21.3                
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 10.16% [2]   10.16% [2]   8.00% [1] 10.16% [2] 10.16% [2] 10.16% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 55.0 [3],[4]   $ 55.0 [3],[4]   $ 55.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 51.7 [3],[4]   51.7 [3],[4]   55.0 [6],[7]            
Investment, Identifier [Axis]: Pluralsight, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.3   0.3   0.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.3   0.3   0.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.3   $ 0.3   $ 0.3            
Investment, Identifier [Axis]: Pluralsight, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.68% [2]   10.68% [2]   9.00% [1] 10.68% [2] 10.68% [2] 10.68% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 106.2 [3],[4]   $ 106.2 [3],[4]   $ 117.7 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 106.2 [3],[4]   106.2 [3],[4]   117.7 [6],[7]            
Investment, Identifier [Axis]: Poplicus Incorporated, Warrant to purchase shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: PosiGen, Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: PosiGen, Inc., Warrant to purchase shares of series D-1 preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: Potomac Intermediate Holdings II LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0   68.4            
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):     (15.9)   0.0            
Total investments at fair value 163.8   163.8   179.7            
Investment, Identifier [Axis]: Potomac Intermediate Holdings II LLC, Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 163.8   163.8   179.7            
Investment, Identifier [Axis]: PracticeTek Purchaser, LLC and GSV PracticeTek Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         8.2            
Investment, Identifier [Axis]: Precinmac (US) Holdings Inc., Trimaster Manufacturing Inc. and Blade Group Holdings, LP. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         15.5            
Less: funded commitments         0.0            
Total unfunded commitments         15.5            
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 commitments         15.5            
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]                      
Total investments at fair value $ 23.8 [4]   $ 23.8 [4]   $ 13.4 [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 9.03% [2]   9.03% [2]   7.00% [1] 9.03% [2] 9.03% [2] 9.03% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 13.8 [3],[4],[5]   $ 13.8 [3],[4],[5]   $ 45.8 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 13.6 [3],[4],[5]   $ 13.6 [3],[4],[5]   45.4 [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 [2] 9.03%   9.03%     9.03% 9.03% 9.03%      
Total first lien senior secured loans [3],[4],[5] $ 4.0   $ 4.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 4.0   $ 4.0                
Investment, Identifier [Axis]: Precinmac (US) Holdings Inc., Trimaster Manufacturing Inc. and Blade Group Holdings, LP., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.03%   9.03%     9.03% 9.03% 9.03%      
Total first lien senior secured loans [3],[4],[5] $ 13.8   $ 13.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 13.7   13.7                
Investment, Identifier [Axis]: Precision Concepts International LLC and Precision Concepts Canada Corporation | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 19.2   19.2                
Less: funded commitments (6.2)   (6.2)                
Total unfunded commitments 13.0   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 commitments $ 13.0   $ 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 [2] 9.15%   9.15%     9.15% 9.15% 9.15%      
Total first lien senior secured loans [3],[4],[5] $ 14.7   $ 14.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 14.7   $ 14.7                
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 [2] 8.78%   8.78%     8.78% 8.78% 8.78%      
Total first lien senior secured loans [3],[4],[5] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 0.1   $ 0.1                
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 [2] 9.05%   9.05%     9.05% 9.05% 9.05%      
Total first lien senior secured loans [3],[4],[5] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 0.1   $ 0.1                
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 [2] 9.15%   9.15%     9.15% 9.15% 9.15%      
Total first lien senior secured loans [3],[4],[5] $ 6.2   $ 6.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 6.2   6.2                
Investment, Identifier [Axis]: Premier Specialties, Inc. and RMCF V CIV XLIV, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.0   11.0   11.0            
Less: funded commitments (1.4)   (1.4)   0.0            
Total unfunded commitments 9.6   9.6   11.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.6   $ 9.6   $ 11.0            
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 9.12% [2]   9.12% [2]   6.75% [1] 9.12% [2] 9.12% [2] 9.12% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 27.3 [3],[4]   $ 27.3 [3],[4]   $ 27.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 25.7 [3],[4]   $ 25.7 [3],[4]   27.3 [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 [2] 9.12%   9.12%     9.12% 9.12% 9.12%      
Total first lien senior secured loans [3],[4] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.3   1.3                
Investment, Identifier [Axis]: Premier Specialties, Inc. and RMCF V CIV XLIV, L.P., Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.4 [4]   2.4 [4]   4.1 [7]            
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 36.0   36.0   36.0            
Less: funded commitments (0.6)   (0.6)   (12.6)            
Total unfunded commitments 35.4   35.4   23.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 35.4   35.4   23.4            
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 13.8 [4]   $ 13.8 [4]   $ 17.5 [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 7.92% [2]   7.92% [2]   3.72% [1] 7.92% [2] 7.92% [2] 7.92% [2] 3.72% [1] 3.72% [1] 3.72% [1]
Total first lien senior secured loans $ 8.6 [3],[4]   $ 8.6 [3],[4]   $ 8.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 8.2 [3],[4]   8.2 [3],[4]   $ 8.6            
Investment, Identifier [Axis]: Premise Health Holding Corp. and OMERS Bluejay Investment Holdings LP, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         3.41%       3.41% 3.41% 3.41%
Total first lien senior secured loans [7],[14]         $ 12.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [15]   $ 0.0 [15]   $ 12.0 [7],[14]            
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 11.67% [2]   11.67% [2]   7.72% [1] 11.67% [2] 11.67% [2] 11.67% [2] 7.72% [1] 7.72% [1] 7.72% [1]
Total first lien senior secured loans $ 67.1 [4]   $ 67.1 [4]   $ 67.1 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 65.1 [4]   65.1 [4]   67.1 [7]            
Investment, Identifier [Axis]: Prime Buyer, L.L.C. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.9   15.9                
Less: funded commitments (2.0)   (2.0)                
Total unfunded commitments 13.9   13.9                
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 commitments $ 13.9   $ 13.9                
Investment, Identifier [Axis]: Prime Buyer, L.L.C., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.50%   10.50%     10.50% 10.50% 10.50%      
Total first lien senior secured loans [3],[4] $ 1.3   $ 1.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.3   $ 1.3                
Investment, Identifier [Axis]: Prime Buyer, L.L.C., First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.40%   7.40%     7.40% 7.40% 7.40%      
Total first lien senior secured loans [3],[4] $ 0.7   $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.6   0.6                
Investment, Identifier [Axis]: Primrose Holding Corporation                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0   0.0            
Redemptions (cost)     0.0   0.0            
Sales (cost)     4.6   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):     28.9   0.0            
Net unrealized gains (losses):     (22.4)   12.9            
Total investments at fair value $ 0.0   $ 0.0   27.0            
Investment, Identifier [Axis]: Primrose Holding Corporation, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 27.0            
Investment, Identifier [Axis]: Priority Holdings, LLC and Priority Technology Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.27% [2]   8.27% [2]   6.75% [1] 8.27% [2] 8.27% [2] 8.27% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 6.7 [3],[4],[5]   $ 6.7 [3],[4],[5]   $ 35.8 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.5 [3],[4],[5]   $ 6.5 [3],[4],[5]   35.8 [6],[7],[8]            
Investment, Identifier [Axis]: Priority Holdings, LLC and Priority Technology Holdings, Inc., Senior preferred stock                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 15.75%   15.75%     15.75% 15.75% 15.75%      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 72.0 [4],[5]   $ 72.0 [4],[5]   68.3 [6],[7],[8]            
Investment, Identifier [Axis]: Priority Holdings, LLC and Priority Technology Holdings, Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [8]         3.4            
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]                      
Total investments at fair value [4],[5] 2.4   2.4                
Investment, Identifier [Axis]: Pritchard Industries, LLC and LJ Pritchard TopCo Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.9   5.9   29.7            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 5.9   5.9   29.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 5.9   5.9   29.7            
Investment, Identifier [Axis]: Pritchard Industries, LLC and LJ Pritchard TopCo Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 9.0 [4]   $ 9.0 [4]   $ 7.9 [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 9.13% [2]   9.13% [2]   6.25% [1] 9.13% [2] 9.13% [2] 9.13% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 97.6 [3],[4]   $ 97.6 [3],[4]   $ 93.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 95.7 [3],[4]   95.7 [3],[4]   92.8 [6],[7]            
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     2.5   11.5            
Redemptions (cost)     0.2   0.1            
Sales (cost)     0.0   0.0            
Interest income     4.5   4.8            
Capital structuring service fees     0.1   0.3            
Dividend income     0.0   0.0            
Other income     0.0   0.0            
Net realized gains (losses):     0.0   0.1            
Net unrealized gains (losses):     33.8   (4.3)            
Total investments at fair value 96.5   96.5   56.3            
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         2.5            
Less: funded commitments         0.0            
Total unfunded commitments         2.5            
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 commitments         2.5            
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 34.6 [4]   $ 34.6 [4]   $ 0.6 [7]            
Investment, Identifier [Axis]: Production Resource Group, L.L.C. and PRG III, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.00%       6.00% 6.00% 6.00%
Total first lien senior secured loans [6],[7]         $ 15.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         15.0            
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 | Rate [2] 11.49%   11.49%     11.49% 11.49% 11.49%      
Total first lien senior secured loans [3],[4] $ 38.3   $ 38.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 38.3   $ 38.3                
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 | Rate [2] 10.49%   10.49%     10.49% 10.49% 10.49%      
Total first lien senior secured loans $ 15.3 [3],[4]   $ 15.3 [3],[4]   34.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 15.3 [3],[4]   $ 15.3 [3],[4]   $ 34.9 [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 | Rate 11.10% [2]   11.10% [2]   8.50% [1] 11.10% [2] 11.10% [2] 11.10% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 7.5 [3],[4]   $ 7.5 [3],[4]   $ 0.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 7.5 [3],[4]   $ 7.5 [3],[4]   0.8 [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 | Rate [2] 11.17%   11.17%     11.17% 11.17% 11.17%      
Total first lien senior secured loans $ 0.8 [3],[4]   $ 0.8 [3],[4]   5.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.8 [3],[4]   0.8 [3],[4]   5.0 [6],[7]            
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 [4] 16.6   16.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 15.8   15.8                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., Series E preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 0.7   0.7                
Investment, Identifier [Axis]: Professional Fighters League, LLC and PFL MMA, Inc., Warrant to purchase up to 3,223,122 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 2.7   2.7                
Investment, Identifier [Axis]: ProfitSolv Purchaser, Inc. and PS Co-Invest, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 13.3   13.3   15.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 13.3   13.3   15.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 13.3   $ 13.3   $ 15.0            
Investment, Identifier [Axis]: ProfitSolv Purchaser, Inc. and PS Co-Invest, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.25% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 5.5 [3],[4]   $ 5.5 [3],[4]   $ 3.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 5.5 [3],[4]   5.5 [3],[4]   3.9 [6],[7]            
Investment, Identifier [Axis]: ProfitSolv Purchaser, Inc. and PS Co-Invest, L.P., Limited partnership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.5 [4]   1.5 [4]   1.6 [7]            
Investment, Identifier [Axis]: Project Alpha Intermediate Holding, Inc. and Qlik Parent, Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.4 [4]   13.4 [4]   16.8 [7]            
Investment, Identifier [Axis]: Project Alpha Intermediate Holding, Inc. and Qlik Parent, Inc., Class B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [4]   $ 0.1 [4]   0.2 [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 [2] 7.12%   7.12%     7.12% 7.12% 7.12%      
Total first lien senior secured loans [4],[11] $ 2.9   $ 2.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[11] 2.7   2.7                
Investment, Identifier [Axis]: Project Essential Bidco, Inc. and Project Essential Super Parent, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.1   1.1   1.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 1.1   1.1   1.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.1   $ 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 6.75% [2]   6.75% [2]   6.75% [1] 6.75% [2] 6.75% [2] 6.75% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 36.3 [3],[4]   $ 36.3 [3],[4]   $ 36.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 34.8 [3],[4]   34.8 [3],[4]   35.8 [6],[7]            
Investment, Identifier [Axis]: Project Essential Bidco, Inc. and Project Essential Super Parent, Inc., Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 29.4 [4]   29.4 [4]   28.5 [6],[7]            
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.5   5.5   43.8            
Less: funded commitments (2.1)   (2.1)   (0.9)            
Total unfunded commitments 3.4   3.4   42.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 3.4   3.4   42.9            
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         1.9            
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., Class B units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.1 [4]   $ 5.1 [4]   $ 0.8 [7]            
Investment, Identifier [Axis]: Project Potter Buyer, LLC and Project Potter Parent, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.25%       9.25% 9.25% 9.25%
Total first lien senior secured loans [6]         $ 44.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 44.1            
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 [2] 10.28%   10.28%     10.28% 10.28% 10.28%      
Total first lien senior secured loans [3],[4] $ 43.8   $ 43.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 43.8   $ 43.8                
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 10.78% [2]   10.78% [2]   9.25% [1] 10.78% [2] 10.78% [2] 10.78% [2] 9.25% [1] 9.25% [1] 9.25% [1]
Total first lien senior secured loans $ 19.2 [3],[4]   $ 19.2 [3],[4]   $ 12.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 19.2 [3],[4]   $ 19.2 [3],[4]   $ 12.9 [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 10.78% [2]   10.78% [2]   9.25% [1] 10.78% [2] 10.78% [2] 10.78% [2] 9.25% [1] 9.25% [1] 9.25% [1]
Total first lien senior secured loans $ 12.8 [3],[4]   $ 12.8 [3],[4]   $ 19.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 12.8 [3],[4]   $ 12.8 [3],[4]   $ 19.4 [6],[7]            
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 10.27% [2]   10.27% [2]   10.50% [1] 10.27% [2] 10.27% [2] 10.27% [2] 10.50% [1] 10.50% [1] 10.50% [1]
Total first lien senior secured loans $ 2.1 [3],[4],[13]   $ 2.1 [3],[4],[13]   $ 0.8 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.1 [3],[4],[13]   $ 2.1 [3],[4],[13]   $ 0.8 [6],[7],[14]            
Investment, Identifier [Axis]: Project Ruby Ultimate Parent Corp. (dba Wellsky), Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.25%       7.25% 7.25% 7.25%
Total first lien senior secured loans [6],[7]         $ 193.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         193.1            
Investment, Identifier [Axis]: Project Ruby Ultimate Parent Corp., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.62%   9.62%     9.62% 9.62% 9.62%      
Total first lien senior secured loans [3],[4] $ 193.1   $ 193.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 185.3   185.3                
Investment, Identifier [Axis]: Proofpoint, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.1   3.1   3.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.1   3.1   3.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.1   $ 3.1   3.1            
Investment, Identifier [Axis]: Proofpoint, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.32%   6.32%     6.32% 6.32% 6.32%      
Total first lien senior secured loans $ 1.0 [3],[4],[11]   $ 1.0 [3],[4],[11]   1.0 [6],[7],[12]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.9 [3],[4],[11]   $ 0.9 [3],[4],[11]   $ 1.0 [6],[7],[12]            
Investment, Identifier [Axis]: Proofpoint, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.32% [2]   9.32% [2]   6.75% [1] 9.32% [2] 9.32% [2] 9.32% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 34.6 [3],[4]   $ 34.6 [3],[4]   $ 34.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 34.6 [3],[4]   34.6 [3],[4]   $ 34.6 [6],[7]            
Investment, Identifier [Axis]: Proofpoint, Inc.,h First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         3.75%       3.75% 3.75% 3.75%
Investment, Identifier [Axis]: Pueblo Mechanical and Controls, LLC and OMERS PMC Investment Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.9   4.9                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 4.9   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 commitments 4.9   4.9                
Investment, Identifier [Axis]: Pueblo Mechanical and Controls, LLC and OMERS PMC Investment Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 9.7   $ 9.7                
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 [2] 8.78%   8.78%     8.78% 8.78% 8.78%      
Total first lien senior secured loans [3],[4] $ 4.9   $ 4.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 4.8   4.8                
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.7   9.7   $ 9.7            
Less: funded commitments (9.7)   (9.7)   (9.7)            
Total unfunded commitments 0.0   0.0   0.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.0   $ 0.0   $ 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 10.12% [2]   10.12% [2]   8.00% [1] 10.12% [2] 10.12% [2] 10.12% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 18.3 [3],[4]   $ 18.3 [3],[4]   $ 18.2 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 18.3 [3],[4]   $ 18.3 [3],[4]   $ 16.8 [6]            
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.12% [2]   10.12% [2]   8.00% [1] 10.12% [2] 10.12% [2] 10.12% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 6.4 [3],[4]   $ 6.4 [3],[4]   $ 6.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.4 [3],[4]   $ 6.4 [3],[4]   $ 5.8 [6],[7]            
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.99% [2]   9.99% [2]   8.00% [1] 9.99% [2] 9.99% [2] 9.99% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 9.7 [3],[4],[13]   $ 9.7 [3],[4],[13]   $ 9.6 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.7 [3],[4],[13]   9.7 [3],[4],[13]   8.8 [6],[7],[14]            
Investment, Identifier [Axis]: Pyramid Management Advisors, LLC and Pyramid Investors, LLC, Preferred membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9   0.9   0.5            
Investment, Identifier [Axis]: QF Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.0   6.0   6.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 6.0   6.0   6.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 6.0   $ 6.0   $ 6.0            
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.25%       7.25% 7.25% 7.25%
Total first lien senior secured loans [6],[7]         $ 8.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 8.1            
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.76%   8.76%     8.76% 8.76% 8.76%      
Total first lien senior secured loans [3],[4] $ 8.1   $ 8.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 8.1   $ 8.1                
Investment, Identifier [Axis]: QF Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.43% [2]   10.43% [2]   7.50% [1] 10.43% [2] 10.43% [2] 10.43% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 6.8 [3],[4]   $ 6.8 [3],[4]   $ 15.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.8 [3],[4]   6.8 [3],[4]   15.5 [6],[7]            
Investment, Identifier [Axis]: R2 Acquisition Corp., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [4]   0.2 [4]   0.5 [7]            
Investment, Identifier [Axis]: RB Holdings InterCo, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.6   5.6                
Less: funded commitments (1.4)   (1.4)                
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 commitments $ 4.2   $ 4.2                
Investment, Identifier [Axis]: RB Holdings InterCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.71%   7.71%     7.71% 7.71% 7.71%      
Total first lien senior secured loans [3],[4] $ 11.5   $ 11.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 11.3   $ 11.3                
Investment, Identifier [Axis]: RB Holdings InterCo, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.83%   7.83%     7.83% 7.83% 7.83%      
Total first lien senior secured loans [3],[4] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.4   1.4                
Investment, Identifier [Axis]: RC V Tecmo Investor LLC, Common member units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 22.6 [4]   22.6 [4]   19.3 [7]            
Investment, Identifier [Axis]: RE Community Holdings GP, LLC and RE Community Holdings, LP, Limited partnership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
Investment, Identifier [Axis]: RE Community Holdings GP, LLC and RE Community Holdings, LP, Limited partnership interest 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
Investment, Identifier [Axis]: RF HP SCF Investor, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 25.3 [4],[5]   25.3 [4],[5]   19.0 [7],[8]            
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc. | Revolving and delayed draw loan commitments                      
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 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]                      
Total investments at fair value [4] $ 5.5   $ 5.5                
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.95%   9.95%     9.95% 9.95% 9.95%      
Total first lien senior secured loans [3],[4] $ 40.2   $ 40.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 39.4   $ 39.4                
Investment, Identifier [Axis]: RMS HoldCo II, LLC & RMS Group Holdings, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.42%   9.42%     9.42% 9.42% 9.42%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: RMS HoldCo II, LLC and RMS Group Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         2.9            
Less: funded commitments         0.0            
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 commitments         2.9            
Investment, Identifier [Axis]: RMS Holdco II, LLC & RMS Group Holdings, Inc., Class A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 4.6            
Investment, Identifier [Axis]: RMS Holdco II, LLC & RMS Group Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 23.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         23.3            
Investment, Identifier [Axis]: RSC Acquisition, Inc. and RSC Insurance Brokerage, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.6   0.6   0.6            
Less: funded commitments 0.0   0.0   (0.3)            
Total unfunded commitments 0.6   0.6   0.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.6   $ 0.6   $ 0.3            
Investment, Identifier [Axis]: RSC Acquisition, Inc. and RSC Insurance Brokerage, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.30% [2]   8.30% [2]   6.25% [1] 8.30% [2] 8.30% [2] 8.30% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 32.9 [3],[4]   $ 32.9 [3],[4]   $ 33.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 31.9 [3],[4]   31.9 [3],[4]   $ 33.1 [6]            
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]         7.75%       7.75% 7.75% 7.75%
Total first lien senior secured loans [6],[7],[14]         $ 0.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[14]         0.3            
Investment, Identifier [Axis]: RTI Surgical, Inc. and Pioneer Surgical Technology, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.9   15.9   15.9            
Less: funded commitments (9.8)   (9.8)   (5.0)            
Total unfunded commitments 6.1   6.1   10.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 6.1   $ 6.1   $ 10.9            
Investment, Identifier [Axis]: RTI Surgical, Inc. and Pioneer Surgical Technology, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.02% [2]   10.02% [2]   8.25% [1] 10.02% [2] 10.02% [2] 10.02% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 22.6 [3],[4]   $ 22.6 [3],[4]   $ 28.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 22.1 [3],[4]   $ 22.1 [3],[4]   $ 28.5 [6]            
Investment, Identifier [Axis]: RTI Surgical, Inc. and Pioneer Surgical Technology, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.57% [2]   9.57% [2]   8.25% [1] 9.57% [2] 9.57% [2] 9.57% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 9.8 [3],[4]   $ 9.8 [3],[4]   $ 5.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.6 [3],[4]   9.6 [3],[4]   5.0 [6],[7]            
Investment, Identifier [Axis]: Radius Aerospace, Inc. and Radius Aerospace Europe Limited | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.7   2.7   2.9            
Less: funded commitments (0.9)   (0.9)   0.0            
Total unfunded commitments 1.8   1.8   2.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.8   $ 1.8   2.9            
Investment, Identifier [Axis]: Radius Aerospace, Inc. and Radius Aerospace Europe Limited, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.94%   7.94%     7.94% 7.94% 7.94%      
Total first lien senior secured loans [3],[4],[5] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 0.2   $ 0.2                
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 [2] 8.80%   8.80%     8.80% 8.80% 8.80%      
Total first lien senior secured loans [3],[4],[5] $ 0.7   $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 0.7   0.7                
Investment, Identifier [Axis]: Raptor Technologies, LLC, Sycamore Bidco LTD and Rocket Parent, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.4   4.4   4.4            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.4   4.4   4.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 4.4   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]                      
Total investments at fair value $ 5.4   $ 5.4   $ 4.8            
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 8.92% [2]   8.92% [2]   7.00% [1] 8.92% [2] 8.92% [2] 8.92% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 8.5 [3],[4],[5]   $ 8.5 [3],[4],[5]   $ 28.5 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.4 [3],[4],[5]   $ 8.4 [3],[4],[5]   $ 28.2 [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 10.42% [2]   10.42% [2]   7.75% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 49.8 [3],[4]   $ 49.8 [3],[4]   $ 93.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 49.8 [3],[4]   $ 49.8 [3],[4]   $ 93.2 [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 10.42% [2]   10.42% [2]   7.75% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 8.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 8.8 [6],[7]            
Investment, Identifier [Axis]: RealPage, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.62% [2]   9.62% [2]   7.25% [1] 9.62% [2] 9.62% [2] 9.62% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 84.1 [3],[4]   $ 84.1 [3],[4]   $ 84.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 83.2 [3],[4]   83.2 [3],[4]   84.1 [6],[7]            
Investment, Identifier [Axis]: Reddy Ice LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.2   0.2   0.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.2   0.2   0.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.2   $ 0.2   $ 0.3            
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.79% [2]   8.79% [2]   7.50% [1] 8.79% [2] 8.79% [2] 8.79% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 61.4 [3],[4]   $ 61.4 [3],[4]   $ 61.9 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 60.8 [3],[4]   $ 60.8 [3],[4]   $ 61.9 [6]            
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.79% [2]   8.79% [2]   7.50% [1] 8.79% [2] 8.79% [2] 8.79% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 12.9 [3],[4]   $ 12.9 [3],[4]   $ 4.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 12.8 [3],[4]   $ 12.8 [3],[4]   $ 4.3 [6],[7]            
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.79% [2]   8.79% [2]   7.50% [1] 8.79% [2] 8.79% [2] 8.79% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 4.3 [3],[4]   $ 4.3 [3],[4]   $ 13.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.2 [3],[4]   4.2 [3],[4]   $ 13.0 [6],[7]            
Investment, Identifier [Axis]: Reddy Ice LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.5   9.5   4.7            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 9.5   9.5   4.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.5   $ 9.5   $ 4.7            
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.87% [2]   9.87% [2]   8.00% [1] 9.87% [2] 9.87% [2] 9.87% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 5.6 [3],[4]   $ 5.6 [3],[4]   $ 1.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.6 [3],[4]   $ 5.6 [3],[4]   $ 1.0 [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 9.78% [2]   9.78% [2]   8.00% [1] 9.78% [2] 9.78% [2] 9.78% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 0.8 [3],[4]   $ 0.8 [3],[4]   $ 12.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.8 [3],[4]   $ 0.8 [3],[4]   12.5 [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 [2] 9.87%   9.87%     9.87% 9.87% 9.87%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
Investment, Identifier [Axis]: Redwood Services, LLC and Redwood Services Holdco, LLC, Series D units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 20.4   20.4   11.6            
Investment, Identifier [Axis]: Reef Lifestyle, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 44.1   44.1   32.8            
Less: funded commitments (34.6)   (34.6)   (13.2)            
Total unfunded commitments 9.5   9.5   19.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.5   $ 9.5   $ 19.6            
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 25.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 25.0            
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.57%   9.57%     9.57% 9.57% 9.57%      
Total first lien senior secured loans [3],[4] $ 24.0   $ 24.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 23.5   $ 23.5                
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.62% [2]   9.62% [2]   8.50% [1] 9.62% [2] 9.62% [2] 9.62% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 1.2 [3],[4]   $ 1.2 [3],[4]   $ 1.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.2 [3],[4]   $ 1.2 [3],[4]   $ 1.1 [6]            
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6],[7],[14]         $ 12.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[14]         $ 12.1            
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured revolving loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.48%   9.48%     9.48% 9.48% 9.48%      
Total first lien senior secured loans [3],[4],[13] $ 33.4   $ 33.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[13] $ 32.8   $ 32.8                
Investment, Identifier [Axis]: Reef Lifestyle, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.62% [2]   9.62% [2]   8.50% [1] 9.62% [2] 9.62% [2] 9.62% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 0.8 [3],[4]   $ 0.8 [3],[4]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.8 [3],[4]   0.8 [3],[4]   0.6 [6],[7]            
Investment, Identifier [Axis]: Regent Education, Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Regent Education, Inc., Warrant to purchase shares of common stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Regent Education, Inc., Warrant to purchase up to 5,393,194 units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: Regent Education, Inc., Warrant to purchase up to 987 units of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: Registrar Intermediate, LLC and PSP Registrar Co-Investment Fund, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.0   28.0   28.0            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 28.0   28.0   28.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 28.0   $ 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 8.12% [2]   8.12% [2]   6.50% [1] 8.12% [2] 8.12% [2] 8.12% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 8.7 [3],[4]   $ 8.7 [3],[4]   $ 37.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 8.7 [3],[4]   8.7 [3],[4]   37.5 [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]                      
Total investments at fair value 2.8 [4]   2.8 [4]   2.6 [7]            
Investment, Identifier [Axis]: Relativity ODA LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.8   3.8   3.8            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.8   3.8   3.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.8   $ 3.8   3.8            
Investment, Identifier [Axis]: Relativity ODA 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 $ 21.9 [3],[4]   $ 21.9 [3],[4]   59.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 21.9 [3],[4]   21.9 [3],[4]   59.8 [6],[7]            
Investment, Identifier [Axis]: Repairify, Inc. and Repairify Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.3   7.3   7.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 7.3   7.3   7.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 7.3   7.3   7.3            
Investment, Identifier [Axis]: Repairify, Inc. and Repairify Holdings, LLC, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.5 [4]   4.5 [4]   4.8 [7]            
Investment, Identifier [Axis]: Respicardia, Inc., Warrant to purchase shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Revalize, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.2   1.2                
Less: funded commitments (0.9)   (0.9)                
Total unfunded commitments 0.3   0.3                
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 commitments $ 0.3   $ 0.3                
Investment, Identifier [Axis]: Revalize, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.42%   9.42%     9.42% 9.42% 9.42%      
Total first lien senior secured loans [3],[4] $ 0.7   $ 0.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.6   $ 0.6                
Investment, Identifier [Axis]: Revalize, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.19%   9.19%     9.19% 9.19% 9.19%      
Total first lien senior secured loans [3],[4] $ 0.9   $ 0.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.9   0.9                
Investment, Identifier [Axis]: Rialto Management Group, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.3   1.3   1.3            
Less: funded commitments (0.2)   (0.2)   (0.2)            
Total unfunded commitments 1.1   1.1   1.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.1   $ 1.1   $ 1.1            
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7],[8]         $ 9.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 9.5            
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.62%   8.62%     8.62% 8.62% 8.62%      
Total first lien senior secured loans [3],[4],[5] $ 0.3   $ 0.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] $ 0.3   $ 0.3                
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   4.34% [1] 8.62% [2] 8.62% [2] 8.62% [2] 4.34% [1] 4.34% [1] 4.34% [1]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [3],[4],[5]   $ 0.7 [8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4],[5]   $ 0.1 [3],[4],[5]   $ 0.7 [8]            
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   4.35% [1] 8.62% [2] 8.62% [2] 8.62% [2] 4.35% [1] 4.35% [1] 4.35% [1]
Total first lien senior secured loans $ 0.1 [3],[4],[5]   $ 0.1 [3],[4],[5]   $ 7.7 [7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4],[5]   0.1 [3],[4],[5]   $ 7.7 [7],[8]            
Investment, Identifier [Axis]: Rialto Management Group, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [5],[15]   0.0 [5],[15]   $ 0.0 [8],[16]            
Investment, Identifier [Axis]: Riser Merger Sub, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.8   2.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 2.8   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 commitments $ 2.8   $ 2.8                
Investment, Identifier [Axis]: Riser Merger Sub, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.62%   8.62%     8.62% 8.62% 8.62%      
Total first lien senior secured loans [3],[4] $ 5.9   $ 5.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 5.8   $ 5.8                
Investment, Identifier [Axis]: Riverview Power LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.68% [2]   12.68% [2]   10.00% [1] 12.68% [2] 12.68% [2] 12.68% [2] 10.00% [1] 10.00% [1] 10.00% [1]
Total first lien senior secured loans $ 50.1 [3],[4]   $ 50.1 [3],[4]   $ 54.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 50.1 [3],[4]   50.1 [3],[4]   54.2 [6],[7]            
Investment, Identifier [Axis]: Rodeo AcquisitionCo LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.2   6.2   6.2            
Less: funded commitments (0.9)   (0.9)   (0.4)            
Total unfunded commitments 5.3   5.3   5.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 5.3   $ 5.3   $ 5.8            
Investment, Identifier [Axis]: Rodeo AcquisitionCo LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.81% [2]   8.81% [2]   7.00% [1] 8.81% [2] 8.81% [2] 8.81% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 17.0 [3],[4]   $ 17.0 [3],[4]   $ 17.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 16.5 [3],[4]   $ 16.5 [3],[4]   $ 16.9 [6],[7]            
Investment, Identifier [Axis]: Rodeo AcquisitionCo LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.82% [2]   8.82% [2]   7.00% [1] 8.82% [2] 8.82% [2] 8.82% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 0.9 [3],[4]   $ 0.9 [3],[4]   $ 0.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9 [3],[4]   0.9 [3],[4]   0.3 [6],[7]            
Investment, Identifier [Axis]: Rug Doctor, LLC and RD 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     0.0   2.4            
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):     (11.2)   (1.1)            
Total investments at fair value 9.9   9.9   21.0            
Investment, Identifier [Axis]: Rug Doctor, LLC and RD Holdco Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: Rug Doctor, LLC and RD Holdco Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 23.9 [4],[9]   23.9 [4],[9]   22.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.9 [4],[9]   9.9 [4],[9]   21.0 [6],[7]            
Investment, Identifier [Axis]: Rug Doctor, LLC and RD Holdco Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         0.0            
Investment, Identifier [Axis]: Rug Doctor, LLC and RD Holdco Inc., Warrant to purchase up to 56,372 shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0                
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):     0.7   (0.3)            
Total investments at fair value 0.2   0.2   0.2            
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC), Class B common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2   0.2   0.2            
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC), Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: S Toys Holdings LLC (fka The Step2 Company, LLC), Warrant to purchase units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: SCI PH Parent, Inc., Series B shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.7 [4]   3.7 [4]   1.2 [7]            
Investment, Identifier [Axis]: SCIH Salt Holdings Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5   7.5            
Less: funded commitments (0.3)   (0.3)   (6.2)            
Total unfunded commitments 7.2   7.2   1.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 7.2   $ 7.2   $ 1.3            
Investment, Identifier [Axis]: SCIH Salt Holdings Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2]   [2]   5.00% [1] [2] [2] [2] 5.00% [1] 5.00% [1] 5.00% [1]
Total first lien senior secured loans [6],[7],[14]         $ 2.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [15]   $ 0.0 [15]   1.9 [6],[7],[14]            
Investment, Identifier [Axis]: SCM Insurance Services Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9   4.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.9   3.9   4.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.9   $ 3.9   $ 4.3            
Investment, Identifier [Axis]: SCM Insurance Services Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.45% [2]   10.45% [2]   6.00% [1] 10.45% [2] 10.45% [2] 10.45% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 60.0 [3],[4],[5]   $ 60.0 [3],[4],[5]   $ 20.4 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 60.0 [3],[4],[5]   $ 60.0 [3],[4],[5]   $ 20.4 [6],[7],[8]            
Investment, Identifier [Axis]: SCM Insurance Services Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         10.00%       10.00% 10.00% 10.00%
Total first lien senior secured loans [6],[7],[8]         $ 60.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[8]         $ 60.0            
Investment, Identifier [Axis]: SE1 Generation, LLC, Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.25% [2]   10.25% [2]   10.25% [1] 10.25% [2] 10.25% [2] 10.25% [2] 10.25% [1] 10.25% [1] 10.25% [1]
Total first lien senior secured loans $ 61.6 [4]   $ 61.6 [4]   $ 58.8 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 60.4 [4]   60.4 [4]   57.0 [7]            
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 15.2   15.2   10.2            
Less: funded commitments (6.4)   (6.4)   0.0            
Total unfunded commitments 8.8   8.8   10.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 8.8   $ 8.8   $ 10.2            
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         5.75%       5.75% 5.75% 5.75%
Total first lien senior secured loans [6]         $ 10.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 10.1            
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.45%   8.45%     8.45% 8.45% 8.45%      
Total first lien senior secured loans [3],[4] $ 10.1   $ 10.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 10.1   $ 10.1                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.45% [2]   8.45% [2]   5.75% [1] 8.45% [2] 8.45% [2] 8.45% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 6.2 [3],[4]   $ 6.2 [3],[4]   $ 6.3 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.2 [3],[4]   $ 6.2 [3],[4]   $ 6.3 [6]            
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.30%   8.30%     8.30% 8.30% 8.30%      
Total first lien senior secured loans [3],[4] $ 0.4   $ 0.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.4   $ 0.4                
Investment, Identifier [Axis]: SFE Intermediate Holdco LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.90%   7.90%     7.90% 7.90% 7.90%      
Total first lien senior secured loans [3] $ 6.4   $ 6.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] $ 6.4   $ 6.4                
Investment, Identifier [Axis]: SG Acquisition, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   5.50% [1] 9.17% [2] 9.17% [2] 9.17% [2] 5.50% [1] 5.50% [1] 5.50% [1]
Total first lien senior secured loans $ 33.8 [3],[4]   $ 33.8 [3],[4]   $ 35.6 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 33.8 [3],[4]   33.8 [3],[4]   35.6 [6]            
Investment, Identifier [Axis]: SHO Holding I Corporation, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 124.9 [4],[9]   124.9 [4],[9]   116.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 82.4 [4],[9]   82.4 [4],[9]   98.9 [6],[7]            
Investment, Identifier [Axis]: SK SPV IV, LLC, Series A common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
Investment, Identifier [Axis]: SK SPV IV, LLC, Series B common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0 [7]            
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc | Revolving and delayed draw loan commitments                      
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 commitments         3.8            
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc. | Revolving and delayed draw loan commitments                      
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 commitments 3.8   3.8                
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc., Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [4]   0.1 [4]   9.6 [7]            
Investment, Identifier [Axis]: SM Wellness Holdings, Inc. and SM Holdco, Inc., Series B units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.7 [4]   9.7 [4]   $ 0.0 [7]            
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.7   22.7                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 22.7   22.7                
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 commitments 22.7   22.7                
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 4.8   4.8                
Investment, Identifier [Axis]: SOC Telemed, Inc. and PSC Spark Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [3],[4] 59.4   59.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 54.7   54.7                
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]                      
Total investments at fair value [4] $ 4.7   $ 4.7                
Investment, Identifier [Axis]: SSE Buyer, Inc., Supply Source Enterprises, Inc., Impact Products LLC, The Safety Zone, LLC and SSE Parent, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 12.89% [2]   12.89% [2]   10.22% [1] 12.89% [2] 12.89% [2] 12.89% [2] 10.22% [1] 10.22% [1] 10.22% [1]
Total first lien senior secured loans $ 20.9 [3],[4]   $ 20.9 [3],[4]   $ 21.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 17.9 [3],[4]   17.9 [3],[4]   19.9 [6],[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]                      
Total investments at fair value 0.2 [4]   0.2 [4]   0.6 [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]                      
Total investments at fair value 0.2 [4]   0.2 [4]   0.6 [7]            
Investment, Identifier [Axis]: SV-Burton Holdings, LLC & LBC Breeze Holdings LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         $ 4.3            
Investment, Identifier [Axis]: SV-Burton Holdings, LLC & LBC Breeze Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 11.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         10.9            
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.6   4.6   7.3            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.6   4.6   7.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 4.6   4.6   7.3            
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.7   $ 4.7                
Investment, Identifier [Axis]: SV-Burton Holdings, LLC and LBC Breeze Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.31%   8.31%     8.31% 8.31% 8.31%      
Total first lien senior secured loans [3],[4] $ 9.0   $ 9.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 8.9   8.9                
Investment, Identifier [Axis]: SVP-Singer Holdings Inc. and SVP-Singer Holdings LP, Class A common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 17.8 [4]   $ 17.8 [4]   $ 24.5 [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 10.42% [2]   10.42% [2]   7.50% [1] 10.42% [2] 10.42% [2] 10.42% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 44.6 [3],[4]   $ 44.6 [3],[4]   $ 44.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 39.2 [3],[4]   $ 39.2 [3],[4]   42.3 [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. | Revolving and delayed draw loan commitments                      
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 commitments         $ 8.5            
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 10.37% [2]   10.37% [2]   8.25% [1] 10.37% [2] 10.37% [2] 10.37% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 48.0 [3],[4]   $ 48.0 [3],[4]   $ 46.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 48.0 [3],[4]   48.0 [3],[4]   46.2 [6],[7]            
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.5   10.5                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 10.5   10.5                
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 commitments $ 10.5   $ 10.5                
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.87%   8.87%     8.87% 8.87% 8.87%      
Total first lien senior secured loans [3],[4] $ 14.1   $ 14.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 14.1   14.1                
Investment, Identifier [Axis]: SageSure Holdings, LLC & Insight Catastrophe Group, LLC, Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 18.2   18.2                
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC and Landscape Parallel Partners, L.P., Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 9.5            
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC and Landscape Parallel Partners, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7]         $ 5.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         5.8            
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services LLC, Tender Lawn Care ULC and Landscape Parallel Partners, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.6   4.6                
Less: funded commitments (0.5)   (0.5)                
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 commitments 4.1   4.1                
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]                      
Total investments at fair value [4] $ 14.9   $ 14.9                
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 [2] 8.83%   8.83%     8.83% 8.83% 8.83%      
Total first lien senior secured loans [3],[4] $ 0.6   $ 0.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.6   $ 0.6                
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 [2] 8.83%   8.83%     8.83% 8.83% 8.83%      
Total first lien senior secured loans [3],[4] $ 0.5   $ 0.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.5   $ 0.5                
Investment, Identifier [Axis]: Schill Landscaping and Lawn Care Services, LLC and Landscape Parallel Partners, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         5.1            
Less: funded commitments         0.0            
Total unfunded commitments         5.1            
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 commitments         $ 5.1            
Investment, Identifier [Axis]: SelectQuote, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.03% [2]   11.03% [2]   5.75% [1] 11.03% [2] 11.03% [2] 11.03% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 22.2 [3],[4]   $ 22.2 [3],[4]   $ 22.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 19.6 [3],[4]   19.6 [3],[4]   22.6 [6],[7]            
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     163.0   232.2            
Redemptions (cost)     29.3   367.7            
Sales (cost)     0.0   0.0            
Interest income     104.5   138.0            
Capital structuring service fees     10.3   18.6            
Dividend income     0.0   0.0            
Other income     4.5   3.8            
Net realized gains (losses):     0.0   0.0            
Net unrealized gains (losses):     0.0   0.0            
Total investments at fair value 1,121.0   1,121.0   987.3            
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC, Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [8]         $ 0.0            
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [5] $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Senior Direct Lending Program, LLC, Subordinated certificates                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.75% [2]   11.75% [2]   8.21% [1] 11.75% [2] 11.75% [2] 11.75% [2] 8.21% [1] 8.21% [1] 8.21% [1]
Total first lien senior secured loans $ 269,806.0 [5],[15]   $ 269,806.0 [5],[15]   $ 987.3 [8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1,121.0 [5],[15]   1,121.0 [5],[15]   987.3 [8]            
Investment, Identifier [Axis]: Shermco Intermediate Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.0   4.0                
Less: funded commitments (3.1)   (3.1)                
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 commitments $ 0.9   $ 0.9                
Investment, Identifier [Axis]: Shermco Intermediate Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.75%   9.75%     9.75% 9.75% 9.75%      
Total first lien senior secured loans [4] $ 3.1   $ 3.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 3.1   3.1                
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     2.7   0.8            
Redemptions (cost)     3.9   1.4            
Sales (cost)     18.9   0.0            
Interest income     0.7   1.4            
Capital structuring service fees     0.0   0.0            
Dividend income     0.0   0.0            
Other income     0.1   0.0            
Net realized gains (losses):     0.0   0.1            
Net unrealized gains (losses):     5.6   4.3            
Total investments at fair value 8.8   8.8   23.1            
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.5   2.5   2.5            
Less: funded commitments (0.3)   (0.3)   (1.2)            
Total unfunded commitments 2.2   2.2   1.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.2   2.2   1.3            
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, Class A preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.1 [4]   3.1 [4]   0.4 [7]            
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, Class C preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.1 [4]   $ 3.1 [4]   $ 0.4 [7]            
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.55% [2]   8.55% [2]   6.00% [1] 8.55% [2] 8.55% [2] 8.55% [2] 6.00% [1] 6.00% [1] 6.00% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 19.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 19.1 [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 10.25% [2]   10.25% [2]   7.25% [1] 10.25% [2] 10.25% [2] 10.25% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 0.2 [3],[4],[13]   $ 0.2 [3],[4],[13]   $ 1.1 [6],[7],[14]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [3],[4],[13]   0.2 [3],[4],[13]   $ 1.1 [6],[7],[14]            
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, First lien senior secured revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7],[14]         $ 0.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[14]         0.1            
Investment, Identifier [Axis]: Shock Doctor, Inc. and Shock Doctor Holdings, LLC, Preferred units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.3   2.3   2.0 [7]            
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co HoldCo, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 8.9            
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co HoldCo, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 27.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 27.0            
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 [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 1.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         1.0            
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.0   5.0   5.0            
Less: funded commitments (2.8)   (2.8)   (1.0)            
Total unfunded commitments 2.2   2.2   4.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.2   2.2   4.0            
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 12.7   $ 12.7                
Investment, Identifier [Axis]: Shur-Co Acquisition, Inc. and Shur-Co Holdco, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.68%   9.68%     9.68% 9.68% 9.68%      
Total first lien senior secured loans [3],[4] $ 26.8   $ 26.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 26.8   $ 26.8                
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 [2] 9.68%   9.68%     9.68% 9.68% 9.68%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.1   $ 0.1                
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 [2] 9.63%   9.63%     9.63% 9.63% 9.63%      
Total first lien senior secured loans [3] $ 2.8   $ 2.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 2.8   2.8                
Investment, Identifier [Axis]: SilverBow Resources, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5],[11] 27.3   27.3                
Investment, Identifier [Axis]: Singer Sewing Company, SVP-Singer Holdings, LLC and SVP-Singer Holdings LP                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)         0.0            
Redemptions (cost)         234.2            
Sales (cost)         0.0            
Interest income         25.4            
Capital structuring service fees         1.9            
Dividend income         6.7            
Other income         0.5            
Net realized gains (losses):         109.7            
Net unrealized gains (losses):         (87.8)            
Total investments at fair value         0.0            
Investment, Identifier [Axis]: SiroMed Physician Services, Inc. and SiroMed Equity Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.1   7.1   7.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 7.1   7.1   7.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 7.1   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]                      
Total investments at fair value $ 1.1 [4]   $ 1.1 [4]   $ 0.7 [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 8.43% [2]   8.43% [2]   5.75% [1] 8.43% [2] 8.43% [2] 8.43% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 10.3 [3],[4]   $ 10.3 [3],[4]   $ 11.5 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 10.3 [3],[4]   10.3 [3],[4]   9.9 [6]            
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.3   3.3                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 3.3   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 commitments 3.3   3.3                
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 8.4   $ 8.4                
Investment, Identifier [Axis]: Smarsh Inc. and Skywalker TopCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.05%   10.05%     10.05% 10.05% 10.05%      
Total first lien senior secured loans [3],[4] $ 10.6   $ 10.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 10.5   10.5                
Investment, Identifier [Axis]: Smarsh Inc., MobileGuard, LLC, Actiance, Inc. and Skywalker TopCo, LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 5.1            
Investment, Identifier [Axis]: Smarsh Inc., MobileGuard, LLC, Actiance, Inc. and Skywalker TopCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.25%       9.25% 9.25% 9.25%
Total first lien senior secured loans [6],[7]         $ 13.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         13.3            
Investment, Identifier [Axis]: SocialFlow, Inc., Warrant to purchase shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 0.0            
Investment, Identifier [Axis]: SocialFlow, Inc., Warrant to purchase up to 215,331 shares of Series C preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Sophia, L.P., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.67% [2]   11.67% [2]   9.00% [1] 11.67% [2] 11.67% [2] 11.67% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 105.9 [3],[4]   $ 105.9 [3],[4]   $ 105.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 103.8 [3],[4]   103.8 [3],[4]   105.9 [6],[7]            
Investment, Identifier [Axis]: SoundCloud Limited, Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.7 [4],[5]   0.7 [4],[5]   0.7 [7],[8]            
Investment, Identifier [Axis]: Spirit RR Holdings, Inc. and Winterfell Co-Invest SCSp | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.2   10.2                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 10.2   10.2                
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 commitments $ 10.2   $ 10.2                
Investment, Identifier [Axis]: Spirit RR Holdings, Inc. and Winterfell Co-Invest SCSp, 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 [3],[4] $ 11.4   $ 11.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 11.2   11.2                
Investment, Identifier [Axis]: Spirit RR Holdings, Inc. and Winterfell Co-Invest SCSp, Limited partner interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 9.8   $ 9.8                
Investment, Identifier [Axis]: Spring Insurance Solutions, LLC | Revolving and delayed draw loan commitments                      
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 commitments         $ 5.6            
Investment, Identifier [Axis]: Spring Insurance Solutions, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.05% [2]   10.05% [2]   7.50% [1] 10.05% [2] 10.05% [2] 10.05% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 22.1 [3],[4]   $ 22.1 [3],[4]   $ 19.7 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 19.7 [3],[4]   $ 19.7 [3],[4]   $ 18.9 [6]            
Investment, Identifier [Axis]: Stamps.com Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.38% [2]   8.38% [2]   6.50% [1] 8.38% [2] 8.38% [2] 8.38% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 147.1 [3],[4]   $ 147.1 [3],[4]   $ 197.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 142.7 [3],[4]   142.7 [3],[4]   193.9 [6],[7]            
Investment, Identifier [Axis]: Star US Bidco LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.5   8.5   8.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 8.5   8.5   8.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 8.5   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            
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: Startec Equity, LLC, Member interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   0.0            
Investment, Identifier [Axis]: Stealth Holding LLC and UCIT Online Security Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.2   1.2   2.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 1.2   1.2   2.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.2   $ 1.2   $ 2.9            
Investment, Identifier [Axis]: Stealth Holding LLC and UCIT Online Security Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.10% [2]   9.10% [2]   7.75% [1] 9.10% [2] 9.10% [2] 9.10% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 52.3 [3],[4],[5]   $ 52.3 [3],[4],[5]   $ 50.5 [6],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 52.3 [3],[4],[5]   $ 52.3 [3],[4],[5]   $ 50.5 [6],[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 9.85% [2]   9.85% [2]   9.00% [1] 9.85% [2] 9.85% [2] 9.85% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 4.0 [3],[4],[5]   $ 4.0 [3],[4],[5]   $ 0.8 [6],[7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.0 [3],[4],[5]   $ 4.0 [3],[4],[5]   0.8 [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 [2] 9.96%   9.96%     9.96% 9.96% 9.96%      
Total first lien senior secured loans [3],[4],[5] $ 1.7   $ 1.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 1.7   1.7                
Investment, Identifier [Axis]: Storable, Inc. and EQT IX Co-Investment (E) SCSP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 7.2 [4],[5]   $ 7.2 [4],[5]   $ 6.8 [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 9.33% [2]   9.33% [2]   7.50% [1] 9.33% [2] 9.33% [2] 9.33% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 42.8 [3],[4]   $ 42.8 [3],[4]   $ 42.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 41.1 [3],[4]   $ 41.1 [3],[4]   42.8 [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 [2] 9.33%   9.33%     9.33% 9.33% 9.33%      
Total first lien senior secured loans [3],[4] $ 10.3   $ 10.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 9.9   9.9                
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class A redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class B redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class C redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class D redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class E redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class F redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class G redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class H redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [4],[5]   1.8 [4],[5]   1.5 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Class I redeemable shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.8 [4],[5]   $ 1.8 [4],[5]   $ 1.5 [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% [2]   3.75% [2]   3.88% [1] 3.75% [2] 3.75% [2] 3.75% [2] 3.88% [1] 3.88% [1] 3.88% [1]
Total first lien senior secured loans $ 60.5 [4],[5]   $ 60.5 [4],[5]   $ 70.2 [7],[8]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 60.5 [4],[5]   60.5 [4],[5]   70.3 [7],[8]            
Investment, Identifier [Axis]: Storm Investment S.a.r.l., Ordinary shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [4],[5]   0.0 [4],[5]   0.0 [7],[8]            
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 30.4   30.4   26.8            
Less: funded commitments (1.2)   (1.2)   0.0            
Total unfunded commitments 29.2   29.2   26.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 29.2   29.2   26.8            
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 9.3 [4]   $ 9.3 [4]   $ 9.2 [7]            
Investment, Identifier [Axis]: Sun Acquirer Corp. and Sun TopCo, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.57% [2]   8.57% [2]   6.50% [1] 8.57% [2] 8.57% [2] 8.57% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 43.3 [3],[4]   $ 43.3 [3],[4]   $ 17.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 42.0 [3],[4]   $ 42.0 [3],[4]   $ 17.2 [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 8.56% [2]   8.56% [2]   6.50% [1] 8.56% [2] 8.56% [2] 8.56% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 15.3 [3],[4]   $ 15.3 [3],[4]   $ 74.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.9 [3],[4]   $ 14.9 [3],[4]   73.7 [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 [2] 11.00%   11.00%     11.00% 11.00% 11.00%      
Total first lien senior secured loans [3],[4],[13] $ 1.0   $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[13] 1.0   1.0                
Investment, Identifier [Axis]: Sundance Energy Inc.                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     0.0   0.0            
Redemptions (cost)     40.9   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):     (22.6)   0.0            
Net unrealized gains (losses):     1.2   (1.1)            
Total investments at fair value 0.0   0.0   68.6            
Investment, Identifier [Axis]: Sundance Energy Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         68.6            
Investment, Identifier [Axis]: Sundance Group Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.6   7.6   7.6            
Less: funded commitments (2.0)   (2.0)   (0.9)            
Total unfunded commitments 5.6   5.6   6.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 5.6   $ 5.6   $ 6.7            
Investment, Identifier [Axis]: Sundance Group Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.54% [2]   8.54% [2]   7.75% [1] 8.54% [2] 8.54% [2] 8.54% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 15.4 [3],[4]   $ 15.4 [3],[4]   $ 15.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 15.3 [3],[4]   $ 15.3 [3],[4]   $ 15.3 [6],[7]            
Investment, Identifier [Axis]: Sundance Group Holdings, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.40% [2]   9.40% [2]   7.75% [1] 9.40% [2] 9.40% [2] 9.40% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 2.0 [3],[4]   $ 2.0 [3],[4]   $ 0.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 2.0 [3],[4]   2.0 [3],[4]   0.9 [6],[7]            
Investment, Identifier [Axis]: Sunk Rock Foundry Partners LP, Hatteras Electrical Manufacturing Holding Company and Sigma Electric Manufacturing Corporation, Diecast Beacon | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.5   7.5   7.5            
Less: funded commitments (0.6)   (0.6)   (0.6)            
Total unfunded commitments 6.9   6.9   6.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 6.9   6.9   $ 6.9            
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]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [15]   $ 0.0 [15]   $ 0.0 [16]            
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% [2]   3.61% [2]   3.61% [1] 3.61% [2] 3.61% [2] 3.61% [2] 3.61% [1] 3.61% [1] 3.61% [1]
Total first lien senior secured loans $ 0.1 [4]   $ 0.1 [4]   $ 0.1 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [4]   $ 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 | Rate 9.53% [2]   9.53% [2]   8.75% [1] 9.53% [2] 9.53% [2] 9.53% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 146.3 [3],[4]   $ 146.3 [3],[4]   $ 142.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 136.1 [3],[4]   136.1 [3],[4]   $ 142.5 [6],[7]            
Investment, Identifier [Axis]: Sunrun Luna Holdco 2021, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 75.0   75.0                
Less: funded commitments (74.7)   (74.7)                
Total unfunded commitments 0.3   0.3                
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 commitments $ 0.3   $ 0.3                
Investment, Identifier [Axis]: Sunrun Luna Holdco 2021, LLC, Senior subordinated revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.29%   6.29%     6.29% 6.29% 6.29%      
Total first lien senior secured loans [4],[5] $ 44.9   $ 44.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 44.9   $ 44.9                
Investment, Identifier [Axis]: Sunrun Luna Holdco 2021, LLC, Senior subordinated revolving loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.66%   10.66%     10.66% 10.66% 10.66%      
Total first lien senior secured loans [4],[5] $ 29.8   $ 29.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] $ 29.8   $ 29.8                
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% [2]   3.98% [2]   3.98% [1] 3.98% [2] 3.98% [2] 3.98% [2] 3.98% [1] 3.98% [1] 3.98% [1]
Total first lien senior secured loans $ 0.4 [4]   $ 0.4 [4]   $ 0.4 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.3 [4]   $ 0.3 [4]   $ 0.4 [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 | Rate 10.43% [2]   10.43% [2]   8.75% [1] 10.43% [2] 10.43% [2] 10.43% [2] 8.75% [1] 8.75% [1] 8.75% [1]
Total first lien senior secured loans $ 71.3 [3],[4]   $ 71.3 [3],[4]   $ 69.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value         69.3            
Investment, Identifier [Axis]: Sunrun Xanadu Issuer 2019-1, LLC and gSunrun Xanadu Holdings 2019-1, LLC, Senior subordinated loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 67.1   67.1                
Investment, Identifier [Axis]: Sunshine Sub, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         5.8            
Less: funded commitments         0.0            
Total unfunded commitments         5.8            
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 commitments         5.8            
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 7.0   7.0   7.0            
Less: funded commitments (3.0)   (3.0)   0.0            
Total unfunded commitments 4.0   4.0   7.0            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 4.0   $ 4.0   $ 7.0            
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.63%   7.63%     7.63% 7.63% 7.63%      
Total first lien senior secured loans [3],[4] $ 12.4   $ 12.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 11.8   $ 11.8                
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] 9.00%   9.00%     9.00% 9.00% 9.00%      
Total first lien senior secured loans [4] $ 3.0   $ 3.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] $ 2.9   $ 2.9                
Investment, Identifier [Axis]: Symplr Software Inc. and Symplr Software Intermediate Holdings, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.93% [2]   9.93% [2]   8.63% [1] 9.93% [2] 9.93% [2] 9.93% [2] 8.63% [1] 8.63% [1] 8.63% [1]
Total first lien senior secured loans $ 76.2 [3],[4]   $ 76.2 [3],[4]   $ 69.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 72.4 [3],[4]   72.4 [3],[4]   69.9 [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]                      
Total investments at fair value 84.0 [4]   84.0 [4]   85.0 [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]                      
Total investments at fair value 42.0 [4]   42.0 [4]   42.6 [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]                      
Total investments at fair value 16.4 [4]   16.4 [4]   16.6 [7]            
Investment, Identifier [Axis]: Synergy HomeCare Franchising, LLC and NP/Synergy Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.2   4.2   4.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 4.2   4.2   4.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 4.2   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]                      
Total investments at fair value $ 0.9   $ 0.9   $ 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 9.42% [2]   9.42% [2]   6.75% [1] 9.42% [2] 9.42% [2] 9.42% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 13.1 [3],[4]   $ 13.1 [3],[4]   $ 15.3 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.1 [3],[4]   13.1 [3],[4]   15.3 [6]            
Investment, Identifier [Axis]: TA/WEG Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.0   2.0   9.3            
Less: funded commitments 0.0   0.0   (0.8)            
Total unfunded commitments 2.0   2.0   8.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.0   $ 2.0   $ 8.5            
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7]         $ 0.1            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 0.1            
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.45%   8.45%     8.45% 8.45% 8.45%      
Total first lien senior secured loans [3],[4] $ 1.6   $ 1.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 1.6   $ 1.6                
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.02% [2]   8.02% [2]   6.75% [1] 8.02% [2] 8.02% [2] 8.02% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.31% [2]   9.31% [2]   6.75% [1] 9.31% [2] 9.31% [2] 9.31% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.57% [2]   7.57% [2]   6.75% [1] 7.57% [2] 7.57% [2] 7.57% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 8.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   $ 8.3 [6],[7]            
Investment, Identifier [Axis]: TA/WEG Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.75%       6.75% 6.75% 6.75%
Total first lien senior secured loans [6],[7],[14]         $ 0.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   0.8 [6],[7],[14]            
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.3   0.3   5.3            
Less: funded commitments (0.1)   (0.1)   0.0            
Total unfunded commitments 0.2   0.2   5.3            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.2   $ 0.2   $ 5.3            
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6]         $ 6.6            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 6.6            
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.18%   9.18%     9.18% 9.18% 9.18%      
Total first lien senior secured loans [3],[4] $ 34.6   $ 34.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 34.2   $ 34.2                
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.50% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 6.5 [3],[4]   $ 6.5 [3],[4]   $ 4.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.5 [3],[4]   $ 6.5 [3],[4]   $ 4.0 [6],[7]            
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6]         $ 34.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         34.8            
Investment, Identifier [Axis]: TCP Hawker Intermediate LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.09%   8.09%     8.09% 8.09% 8.09%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.1   0.1                
Investment, Identifier [Axis]: THG Acquisition, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 28.8   28.8   34.8            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 28.8   28.8   34.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 28.8   $ 28.8   $ 34.8            
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.87% [2]   8.87% [2]   6.25% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 14.9 [3],[4]   $ 14.9 [3],[4]   $ 0.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.9 [3],[4]   $ 14.9 [3],[4]   $ 0.6 [6],[7]            
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   6.75% [1] 8.62% [2] 8.62% [2] 8.62% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 6.5 [3],[4]   $ 6.5 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 6.5 [3],[4]   $ 6.5 [3],[4]   $ 0.1 [6],[7]            
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.87% [2]   8.87% [2]   6.50% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 23.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   $ 23.2 [6],[7]            
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6]         $ 14.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 14.9            
Investment, Identifier [Axis]: THG Acquisition, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Tamarack Intermediate, L.L.C. and Tamarack Parent, L.L.C. | Revolving and delayed draw loan commitments                      
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 commitments 7.5   7.5                
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]                      
Total investments at fair value $ 5.4   $ 5.4                
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 [2] 9.23%   9.23%     9.23% 9.23% 9.23%      
Total first lien senior secured loans [3] $ 35.2   $ 35.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] 34.9   34.9                
Investment, Identifier [Axis]: Taymax Group, L.P., Taymax Group G.P., LLC, PF Salem Canada ULC and TCP Fit Parent, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.7   1.7   1.9            
Less: funded commitments (0.8)   (0.8)   (0.5)            
Total unfunded commitments 0.9   0.9   1.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   (0.3)            
Total net adjusted unfunded revolving and delayed draw commitments 0.9   0.9   1.1            
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]                      
Total investments at fair value $ 3.4   $ 3.4   $ 2.0            
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 8.92% [2]   8.92% [2]   6.25% [1] 8.92% [2] 8.92% [2] 8.92% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 1.4 [3],[4]   $ 1.4 [3],[4]   $ 1.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.4 [3],[4]   $ 1.4 [3],[4]   $ 1.1 [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 8.92% [2]   8.92% [2]   6.75% [1] 8.92% [2] 8.92% [2] 8.92% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.8 [3],[4]   $ 0.8 [3],[4]   $ 0.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.8 [3],[4]   $ 0.8 [3],[4]   $ 0.5 [6],[7]            
Investment, Identifier [Axis]: Teasdale Foods, Inc. and Familia Group Holdings Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.88% [2]   9.88% [2]   8.00% [1] 9.88% [2] 9.88% [2] 9.88% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 75.8 [3],[4]   $ 75.8 [3],[4]   $ 78.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 65.1 [3],[4]   65.1 [3],[4]   73.6 [6],[7]            
Investment, Identifier [Axis]: Teasdale Foods, Inc. and Familia Group Holdings Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
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]                      
Total investments at fair value $ 0.0   $ 0.0                
Investment, Identifier [Axis]: Teligent, Inc, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7],[10]         8.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[10]         8.8            
Investment, Identifier [Axis]: Teligent, Inc, Second lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7],[10]         1.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[10]         0.5            
Investment, Identifier [Axis]: Teligent, Inc, Second lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans [7],[10]         77.8            
Participating interest sold         0.6            
Secured borrowings         0.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7],[10]         $ 29.5            
Investment, Identifier [Axis]: Teligent, Inc, Second lien senior secured loan 3, Secured borrowing                      
Schedule of Investments [Line Items]                      
Coupon | Rate         14.50%       14.50% 14.50% 14.50%
Investment, Identifier [Axis]: Teligent, Inc, Series D preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         $ 0.0            
Investment, Identifier [Axis]: Teligent, Inc, Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Teligent, Inc, Warrant to purchase shares of common stock 2                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
Investment, Identifier [Axis]: Teligent, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         3.4            
Less: funded commitments         0.0            
Total unfunded commitments         3.4            
Less: commitments substantially at discretion of the Company         0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions         (3.4)            
Total net adjusted unfunded revolving and delayed draw commitments         0.0            
Investment, Identifier [Axis]: Tempus Labs, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.49%   10.49%     10.49% 10.49% 10.49%      
Total first lien senior secured loans [3],[4] $ 71.4   $ 71.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 69.6   69.6                
Investment, Identifier [Axis]: TerSera Therapeutics LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.1   0.1   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.1   $ 0.1   $ 0.1            
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.27% [2]   9.27% [2]   6.60% [1] 9.27% [2] 9.27% [2] 9.27% [2] 6.60% [1] 6.60% [1] 6.60% [1]
Total first lien senior secured loans $ 5.0 [3],[4]   $ 5.0 [3],[4]   $ 5.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.0 [3],[4]   $ 5.0 [3],[4]   $ 5.1 [6]            
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.85% [2]   7.85% [2]   6.60% [1] 7.85% [2] 7.85% [2] 7.85% [2] 6.60% [1] 6.60% [1] 6.60% [1]
Total first lien senior secured loans $ 2.1 [3],[4]   $ 2.1 [3],[4]   $ 2.1 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.1 [3],[4]   $ 2.1 [3],[4]   $ 2.1 [6]            
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.27% [2]   9.27% [2]   6.60% [1] 9.27% [2] 9.27% [2] 9.27% [2] 6.60% [1] 6.60% [1] 6.60% [1]
Total first lien senior secured loans $ 1.8 [3],[4]   $ 1.8 [3],[4]   $ 1.8 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.8 [3],[4]   1.8 [3],[4]   $ 1.8 [6]            
Investment, Identifier [Axis]: TerSera Therapeutics LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [16]         $ 0.0            
Investment, Identifier [Axis]: The Alaska Club Partners, LLC, Athletic Club Partners LLC and The Alaska Club, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.1   1.1   1.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 1.1   1.1   1.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 1.1   $ 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 | Rate 12.75% [2]   12.75% [2]   10.25% [1] 12.75% [2] 12.75% [2] 12.75% [2] 10.25% [1] 10.25% [1] 10.25% [1]
Total first lien senior secured loans $ 12.6 [3],[4]   $ 12.6 [3],[4]   $ 15.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 12.6 [3],[4]   12.6 [3],[4]   14.1 [6],[7]            
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 12.6   12.6   29.5            
Less: funded commitments (10.1)   (10.1)   (2.0)            
Total unfunded commitments 2.5   2.5   27.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.5   2.5   27.5            
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.3   $ 8.3   $ 4.9            
Investment, Identifier [Axis]: The Arcticom Group, LLC and AMCP Mechanical Holdings, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.49% [2]   8.49% [2]   6.75% [1] 8.49% [2] 8.49% [2] 8.49% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 28.9 [3],[4]   $ 28.9 [3],[4]   $ 47.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 28.6 [3],[4]   $ 28.6 [3],[4]   $ 46.7 [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 [2] 9.57%   9.57%     9.57% 9.57% 9.57%      
Total first lien senior secured loans [3],[4] $ 11.5   $ 11.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 11.4   $ 11.4                
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 11.25% [2]   11.25% [2]   8.25% [1] 11.25% [2] 11.25% [2] 11.25% [2] 8.25% [1] 8.25% [1] 8.25% [1]
Total first lien senior secured loans $ 5.4 [3],[4]   $ 5.4 [3],[4]   $ 2.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.4 [3],[4]   $ 5.4 [3],[4]   2.0 [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 [2] 9.15%   9.15%     9.15% 9.15% 9.15%      
Total first lien senior secured loans [3],[4] $ 4.6   $ 4.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 4.6   $ 4.6                
Investment, Identifier [Axis]: The Edelman Financial Center, LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.87%   9.87%     9.87% 9.87% 9.87%      
Total first lien senior secured loans [4],[5] $ 5.4   $ 5.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 4.8   4.8                
Investment, Identifier [Axis]: The Mather Group, LLC, TVG-TMG Topco, Inc., and TVG-TMG Holdings, LLC | Revolving and delayed draw loan commitments                      
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 commitments 1.9   1.9                
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]                      
Total investments at fair value [5] $ 0.0   $ 0.0                
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 [2] 8.41%   8.41%     8.41% 8.41% 8.41%      
Total first lien senior secured loans [3],[4],[5] $ 3.3   $ 3.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 3.3   3.3                
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 [4],[5] 2.9   2.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[5] 2.8   2.8                
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]                      
Total investments at fair value [4],[5] 7.2   7.2                
Investment, Identifier [Axis]: The NPD Group, L.P., IRI Group Holdings, Inc., Information Resources, Inc. and IRI-NPD Co-Invest Aggregator, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 14.4   14.4                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 14.4   14.4                
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 commitments 14.4   14.4                
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]                      
Total investments at fair value [4] $ 11.3   $ 11.3                
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 | Rate [2] 8.76%   8.76%     8.76% 8.76% 8.76%      
Total first lien senior secured loans [3],[4] $ 212.0   $ 212.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 207.7   207.7                
Investment, Identifier [Axis]: The Teaching Company Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0   0.0   1.2 [7]            
Investment, Identifier [Axis]: The Teaching Company Holdings, Inc., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.1 [4]   3.1 [4]   2.9 [7]            
Investment, Identifier [Axis]: The Ultimate Software Group, Inc. and H&F Unite Partners, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 10.0   10.0   10.0            
Less: funded commitments (1.0)   (1.0)   (0.1)            
Total unfunded commitments 9.0   9.0   9.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.0   $ 9.0   $ 9.9            
Investment, Identifier [Axis]: The Ultimate Software Group, Inc. and H&F Unite Partners, L.P., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.87% [2]   6.87% [2]   0.00% [1] 6.87% [2] 6.87% [2] 6.87% [2] 0.00% [1] 0.00% [1] 0.00% [1]
Total first lien senior secured loans [4],[5],[13] $ 0.9   $ 0.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.9 [4],[5],[13]   0.9 [4],[5],[13]   $ 0.0 [8],[16]            
Investment, Identifier [Axis]: The Ultimate Software Group, Inc. and H&F Unite Partners, L.P., Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 13.5 [4],[5]   13.5 [4],[5]   15.1 [7],[8]            
Investment, Identifier [Axis]: The Ultimus Group Midco, LLC, The Ultimus Group, LLC, and The Ultimus Group Aggregator, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 6.9   6.9   6.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 6.9   6.9   6.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 6.9   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]                      
Total investments at fair value 2.4   2.4   1.9            
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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value 0.0   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]                      
Total investments at fair value $ 0.0   $ 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 8.17% [2]   8.17% [2]   5.75% [1] 8.17% [2] 8.17% [2] 8.17% [2] 5.75% [1] 5.75% [1] 5.75% [1]
Total first lien senior secured loans $ 37.5 [3],[4]   $ 37.5 [3],[4]   $ 37.8 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 37.1 [3],[4]   37.1 [3],[4]   37.8 [6]            
Investment, Identifier [Axis]: Therapy Brands Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.6   8.6   8.6            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 8.6   8.6   8.6            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 8.6   $ 8.6   $ 8.6            
Investment, Identifier [Axis]: Therapy Brands Holdings LLC, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.74% [2]   9.74% [2]   7.50% [1] 9.74% [2] 9.74% [2] 9.74% [2] 7.50% [1] 7.50% [1] 7.50% [1]
Total first lien senior secured loans $ 20.5 [3],[4]   $ 20.5 [3],[4]   $ 20.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 19.4 [3],[4]   19.4 [3],[4]   20.5 [6],[7]            
Investment, Identifier [Axis]: Thermostat Purchaser III, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.7   11.7   11.7            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 11.7   11.7   11.7            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 11.7   $ 11.7   $ 11.7            
Investment, Identifier [Axis]: Thermostat Purchaser III, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.32% [2]   10.32% [2]   8.00% [1] 10.32% [2] 10.32% [2] 10.32% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 23.0 [3],[4]   $ 23.0 [3],[4]   $ 23.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 21.8 [3],[4]   21.8 [3],[4]   22.8 [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. | Revolving and delayed draw loan commitments                      
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 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 senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.05%   8.05%     8.05% 8.05% 8.05%      
Total first lien senior secured loans [3],[4],[11] $ 10.9   $ 10.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] 9.7   9.7                
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]                      
Total investments at fair value [4] $ 10.9   $ 10.9                
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 [2] 12.05%   12.05%     12.05% 12.05% 12.05%      
Total first lien senior secured loans [3],[4] $ 85.3   $ 85.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 70.8   $ 70.8                
Investment, Identifier [Axis]: TibCo Software Inc., Picard Parent, Inc., Picard MidCo, Inc., Picard HoldCo, LLC and Elliott Alto Co-Investor Aggregator L.P., Senior secured notes                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 6.50%   6.50%     6.50% 6.50% 6.50%      
Total first lien senior secured loans [4],[11] $ 88.9   $ 88.9                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[11] 75.0   75.0                
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]                      
Total investments at fair value [4] 134.8   134.8                
Investment, Identifier [Axis]: Top Five Largest Portfolio Company Investments | Senior Direct Lending Program                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 1,616.0   1,616.0   1,540.0            
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):     (0.6)   (1.5)            
Total investments at fair value 3.3   3.3   3.9            
Investment, Identifier [Axis]: Totes Isotoner Corporation and Totes Ultimate Holdco, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0   $ 0.0   $ 0.4 [7]            
Investment, Identifier [Axis]: Totes Isotoner Corporation and Totes Ultimate Holdco, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.12% [2]   9.12% [2]   7.00% [1] 9.12% [2] 9.12% [2] 9.12% [2] 7.00% [1] 7.00% [1] 7.00% [1]
Total first lien senior secured loans $ 2.2 [3],[4]   $ 2.2 [3],[4]   $ 2.2 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 1.8 [3],[4]   $ 1.8 [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 7.12% [2]   7.12% [2]   5.00% [1] 7.12% [2] 7.12% [2] 7.12% [2] 5.00% [1] 5.00% [1] 5.00% [1]
Total first lien senior secured loans $ 1.6 [3],[4]   $ 1.6 [3],[4]   $ 1.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 1.5 [3],[4]   1.5 [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]                      
Total investments at fair value $ 2.1 [4]   $ 2.1 [4]   $ 2.8 [7]            
Investment, Identifier [Axis]: Triton Water Holdings, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.17% [2]   7.17% [2]   4.00% [1] 7.17% [2] 7.17% [2] 7.17% [2] 4.00% [1] 4.00% [1] 4.00% [1]
Total first lien senior secured loans $ 1.0 [3],[4],[11]   $ 1.0 [3],[4],[11]   $ 1.0 [6],[7],[12]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.9 [3],[4],[11]   $ 0.9 [3],[4],[11]   $ 1.0 [6],[7],[12]            
Investment, Identifier [Axis]: Triton Water Holdings, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 6.25% [2]   6.25% [2]   6.25% [1] 6.25% [2] 6.25% [2] 6.25% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 0.1 [4],[11]   $ 0.1 [4],[11]   $ 0.1 [7],[12]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [4],[11]   0.1 [4],[11]   0.1 [7],[12]            
Investment, Identifier [Axis]: Two Six Labs, LLC | Revolving and delayed draw loan commitments                      
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 commitments 10.3   10.3                
Investment, Identifier [Axis]: Tyden Group Holding Corp., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [8]         3.9            
Investment, Identifier [Axis]: Tyden Group Holding Corp., Preferred stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [8]         0.4            
Investment, Identifier [Axis]: U.S. Anesthesia Partners, Inc. & U.S. Anesthesia Partners Holdings, Inc., Common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.4 [4]   $ 14.4 [4]   $ 12.9 [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 10.06% [2]   10.06% [2]   8.00% [1] 10.06% [2] 10.06% [2] 10.06% [2] 8.00% [1] 8.00% [1] 8.00% [1]
Total first lien senior secured loans $ 147.8 [3],[4]   $ 147.8 [3],[4]   $ 147.8 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 143.3 [3],[4]   143.3 [3],[4]   146.3 [6],[7]            
Investment, Identifier [Axis]: US Salt Investors, LLC and Emerald Lake Pearl Acquisition-A, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 9.9   9.9   9.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 9.9   9.9   9.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 9.9   $ 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 9.17% [2]   9.17% [2]   6.25% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 26.4 [3],[4]   $ 26.4 [3],[4]   $ 40.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 25.4 [3],[4]   25.4 [3],[4]   39.7 [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]                      
Total investments at fair value 0.5 [4]   0.5 [4]   0.8 [7]            
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 18.4   18.4   8.4            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 18.4   18.4   8.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 18.4   $ 18.4   8.4            
Investment, Identifier [Axis]: United Digestive MSO Parent, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.07%   8.07%     8.07% 8.07% 8.07%      
Total first lien senior secured loans [3],[4] $ 1.0   $ 1.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.0   1.0                
Investment, Identifier [Axis]: VCP-EDC Co-Invest, LLC, Membership units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 3.5   3.5   0.4            
Investment, Identifier [Axis]: VLS Recovery Services, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         23.8            
Less: funded commitments         (1.5)            
Total unfunded commitments         22.3            
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 commitments         $ 22.3            
Investment, Identifier [Axis]: VLS Recovery Services, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 8.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 8.8            
Investment, Identifier [Axis]: VLS Recovery Services, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7]         $ 5.2            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 5.2            
Investment, Identifier [Axis]: VLS Recovery Services, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         6.50%       6.50% 6.50% 6.50%
Total first lien senior secured loans [6],[7],[14]         $ 1.3            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7],[14]         1.3            
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 11.7   11.7   6.2            
Less: funded commitments (0.2)   (0.2)   0.0            
Total unfunded commitments 11.5   11.5   6.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 11.5   11.5   6.2            
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., Class A-2 units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 7.4 [4]   $ 7.4 [4]   $ 7.5 [7]            
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.13% [2]   9.13% [2]   6.75% [1] 9.13% [2] 9.13% [2] 9.13% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 3.3 [3],[4]   $ 3.3 [3],[4]   $ 6.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 3.3 [3],[4]   $ 3.3 [3],[4]   6.4 [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 [2] 9.37%   9.37%     9.37% 9.37% 9.37%      
Total first lien senior secured loans [3],[4] $ 2.5   $ 2.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 2.5   $ 2.5                
Investment, Identifier [Axis]: VPP Intermediate Holdings, LLC and VPP Group Holdings, L.P., First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.57%   8.57%     8.57% 8.57% 8.57%      
Total first lien senior secured loans [3] $ 0.5   $ 0.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] $ 0.5   $ 0.5                
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 [2] 11.50%   11.50%     11.50% 11.50% 11.50%      
Total first lien senior secured loans [3],[13] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[13] 0.1   0.1                
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC                      
Investments Activity And Fair Value Table [Abstract]                      
Purchases (cost)     6.0   0.9            
Redemptions (cost)     4.5   0.0            
Sales (cost)     0.0   0.0            
Interest income     3.6   4.0            
Capital structuring service fees     0.2   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):     24.4   5.4            
Total investments at fair value 107.0   107.0   77.5            
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         7.1            
Less: funded commitments         0.0            
Total unfunded commitments         7.1            
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 commitments         7.1            
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 64.3 [4]   64.3 [4]   39.9 [7]            
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 27.3 [3],[4]   27.3 [3],[4]   7.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 27.3 [3],[4]   27.3 [3],[4]   7.0 [6],[7]            
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 9.4 [3],[4]   9.4 [3],[4]   5.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 9.4 [3],[4]   9.4 [3],[4]   5.5 [6],[7]            
Investment, Identifier [Axis]: VPROP Operating, LLC and V SandCo, LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 6.0 [3],[4]   6.0 [3],[4]   25.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 6.0 [3],[4]   6.0 [3],[4]   25.1 [6],[7]            
Investment, Identifier [Axis]: VRC Companies, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 5.4   5.4                
Less: funded commitments (0.8)   (0.8)                
Total unfunded commitments 4.6   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 commitments $ 4.6   $ 4.6                
Investment, Identifier [Axis]: VRC Companies, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.42%   8.42%     8.42% 8.42% 8.42%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.1   $ 0.1                
Investment, Identifier [Axis]: VRC Companies, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.75%   10.75%     10.75% 10.75% 10.75%      
Total first lien senior secured loans [3] $ 0.8   $ 0.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3] $ 0.8   $ 0.8                
Investment, Identifier [Axis]: VRC Companies, LLC, Senior subordinated 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 [4] $ 5.0   $ 5.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4] 5.0   5.0                
Investment, Identifier [Axis]: VS Buyer, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.1   8.1   8.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 8.1   8.1   8.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 8.1   8.1   8.1            
Investment, Identifier [Axis]: VSC Investors LLC, Membership interest                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.5 [4],[5],[11]   0.5 [4],[5],[11]   0.6 [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]                      
Total investments at fair value $ 1.1 [4]   $ 1.1 [4]   $ 0.7 [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 [2] 6.62%   6.62%     6.62% 6.62% 6.62%      
Total first lien senior secured loans [3],[4],[11] $ 9.7   $ 9.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[11] $ 9.0   $ 9.0                
Investment, Identifier [Axis]: Varsity Brands Holding Co., Inc. and BCPE Hercules Holdings, LP, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 11.37% [2]   11.37% [2]   9.25% [1] 11.37% [2] 11.37% [2] 11.37% [2] 9.25% [1] 9.25% [1] 9.25% [1]
Total first lien senior secured loans $ 122.7 [3],[4]   $ 122.7 [3],[4]   $ 21.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 121.5 [3],[4]   $ 121.5 [3],[4]   $ 20.3 [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 11.37% [2]   11.37% [2]   9.25% [1] 11.37% [2] 11.37% [2] 11.37% [2] 9.25% [1] 9.25% [1] 9.25% [1]
Total first lien senior secured loans $ 21.1 [3],[4]   $ 21.1 [3],[4]   $ 122.7 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 20.9 [3],[4]   20.9 [3],[4]   117.9 [6]            
Investment, Identifier [Axis]: Verista, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.2   8.2                
Less: funded commitments (1.1)   (1.1)                
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 commitments $ 7.1   $ 7.1                
Investment, Identifier [Axis]: Verista, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.74%   8.74%     8.74% 8.74% 8.74%      
Total first lien senior secured loans [3],[4] $ 0.8   $ 0.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.8   $ 0.8                
Investment, Identifier [Axis]: Verista, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.24%   9.24%     9.24% 9.24% 9.24%      
Total first lien senior secured loans [3],[4] $ 1.1   $ 1.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.1   1.1                
Investment, Identifier [Axis]: Verscend Holding Corp. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.5   22.5   22.5            
Less: funded commitments 0.0   0.0   (0.1)            
Total unfunded commitments 22.5   22.5   22.4            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 22.5   22.5   $ 22.4            
Investment, Identifier [Axis]: Verscend Holding Corp., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: Vertice Pharma UK Parent Limited, Preferred shares                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.0 [5]   $ 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 [2] 6.87%   6.87%     6.87% 6.87% 6.87%      
Total first lien senior secured loans [4],[11] $ 0.3   $ 0.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [4],[11] $ 0.3   $ 0.3                
Investment, Identifier [Axis]: Visual Edge Technology, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.07% [2]   10.07% [2]   9.75% [1] 10.07% [2] 10.07% [2] 10.07% [2] 9.75% [1] 9.75% [1] 9.75% [1]
Total first lien senior secured loans $ 32.6 [3],[4]   $ 32.6 [3],[4]   $ 32.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 30.0 [3],[4]   30.0 [3],[4]   30.9 [6],[7]            
Investment, Identifier [Axis]: Visual Edge Technology, Inc., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Total first lien senior secured loans 99.8 [4],[9]   99.8 [4],[9]   88.6 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 62.4 [4],[9]   62.4 [4],[9]   79.7 [7]            
Investment, Identifier [Axis]: Visual Edge Technology, Inc., Warrant to purchase shares of common stock                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [7]         0.0            
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]                      
Total investments at fair value 0.0   0.0                
Investment, Identifier [Axis]: WA Asset Management, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.8   0.8                
Less: funded commitments 0.0   0.0                
Total unfunded commitments 0.8   0.8                
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 commitments $ 0.8   $ 0.8                
Investment, Identifier [Axis]: WA Asset Management, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.20%   9.20%     9.20% 9.20% 9.20%      
Total first lien senior secured loans [3],[4],[5] $ 4.0   $ 4.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[5] 4.0   4.0                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments         10.3            
Less: funded commitments         (1.5)            
Total unfunded commitments         8.8            
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 commitments         $ 8.8            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 35.4   35.4                
Less: funded commitments (5.2)   (5.2)                
Total unfunded commitments 30.2   30.2                
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 commitments 30.2   30.2                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, Common units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.8   $ 4.8                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC and WSHP FC Holdings LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 9.95%   9.95%     9.95% 9.95% 9.95%      
Total first lien senior secured loans [3],[4] $ 33.2   $ 33.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 32.8   $ 32.8                
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 [2] 9.95%   9.95%     9.95% 9.95% 9.95%      
Total first lien senior secured loans [3],[4] $ 14.6   $ 14.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 14.4   $ 14.4                
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 [2] 9.95%   9.95%     9.95% 9.95% 9.95%      
Total first lien senior secured loans [3],[4] $ 10.7   $ 10.7                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 10.6   $ 10.6                
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 [2] 9.95%   9.95%     9.95% 9.95% 9.95%      
Total first lien senior secured loans [3],[4] $ 11.3   $ 11.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 11.2   $ 11.2                
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 [2] 9.95%   9.95%     9.95% 9.95% 9.95%      
Total first lien senior secured loans [3],[4] $ 4.5   $ 4.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 4.5   $ 4.5                
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 [2] 9.80%   9.80%     9.80% 9.80% 9.80%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.1   $ 0.1                
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 [2] 9.80%   9.80%     9.80% 9.80% 9.80%      
Total first lien senior secured loans [3],[4] $ 0.1   $ 0.1                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 0.1   $ 0.1                
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 [2] 9.55%   9.55%     9.55% 9.55% 9.55%      
Total first lien senior secured loans [3],[4],[13] $ 4.5   $ 4.5                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4],[13] $ 4.4   $ 4.4                
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 4.9            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 4.9            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 33.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 33.4            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 4.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 4.5            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 11.4            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 11.4            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured loan 5                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6]         $ 10.8            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 10.8            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured loan 6                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 9.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 9.0            
Investment, Identifier [Axis]: WSHP FC Acquisition LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         7.00%       7.00% 7.00% 7.00%
Total first lien senior secured loans [6],[7]         $ 1.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 1.5            
Investment, Identifier [Axis]: Walnut Parent, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.56% [2]   8.56% [2]   6.50% [1] 8.56% [2] 8.56% [2] 8.56% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 14.7 [3],[4]   $ 14.7 [3],[4]   $ 14.9 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 14.5 [3],[4]   $ 14.5 [3],[4]   $ 14.9 [6]            
Investment, Identifier [Axis]: Walnut Parent, Inc., First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.56% [2]   8.56% [2]   6.50% [1] 8.56% [2] 8.56% [2] 8.56% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 19.9 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 19.9 [6],[7]            
Investment, Identifier [Axis]: Wand Newco 3, Inc., Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.37% [2]   10.37% [2]   7.43% [1] 10.37% [2] 10.37% [2] 10.37% [2] 7.43% [1] 7.43% [1] 7.43% [1]
Total first lien senior secured loans $ 182.6 [4]   $ 182.6 [4]   $ 180.2 [7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 178.9 [4]   $ 178.9 [4]   $ 180.2 [7]            
Investment, Identifier [Axis]: Wash Encore Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.78% [2]   8.78% [2]   6.75% [1] 8.78% [2] 8.78% [2] 8.78% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 134.6 [3],[4]   $ 134.6 [3],[4]   $ 135.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 131.9 [3],[4]   131.9 [3],[4]   134.2 [6],[7]            
Investment, Identifier [Axis]: Watchfire Enterprises, Inc. | Revolving and delayed draw loan commitments                      
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 commitments         2.0            
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 1.9   1.9   1.9            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 1.9   1.9   1.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 1.9   1.9   1.9            
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 2.9   $ 2.9   $ 2.7            
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.17% [2]   9.17% [2]   6.25% [1] 9.17% [2] 9.17% [2] 9.17% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 19.3 [3],[4]   $ 19.3 [3],[4]   $ 19.4 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 19.3 [3],[4]   19.3 [3],[4]   $ 19.4 [6]            
Investment, Identifier [Axis]: Watermill Express, LLC and Watermill Express Holdings, LLC, First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         0.00%       0.00% 0.00% 0.00%
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.0 [15]   0.0 [15]   $ 0.0 [16]            
Investment, Identifier [Axis]: WebPT, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.9   0.9   0.1            
Less: funded commitments (0.2)   (0.2)   0.0            
Total unfunded commitments 0.7   0.7   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.7   $ 0.7   $ 0.1            
Investment, Identifier [Axis]: WebPT, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.82% [2]   9.82% [2]   7.75% [1] 9.82% [2] 9.82% [2] 9.82% [2] 7.75% [1] 7.75% [1] 7.75% [1]
Total first lien senior secured loans $ 48.1 [3],[4]   $ 48.1 [3],[4]   $ 48.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 48.1 [3],[4]   $ 48.1 [3],[4]   48.1 [6],[7]            
Investment, Identifier [Axis]: WebPT, Inc., First lien senior secured revolving loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.38%   8.38%     8.38% 8.38% 8.38%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
Investment, Identifier [Axis]: Wellness AcquisitionCo, Inc. | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 3.9   3.9   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 3.9   3.9   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.9   $ 3.9   $ 0.1            
Investment, Identifier [Axis]: Wellness AcquisitionCo, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.62% [2]   8.62% [2]   6.50% [1] 8.62% [2] 8.62% [2] 8.62% [2] 6.50% [1] 6.50% [1] 6.50% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 0.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.1 [3],[4]   0.1 [3],[4]   0.1 [6],[7]            
Investment, Identifier [Axis]: Wellness AcquisitionCo, Inc., First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [15] 0.0   0.0                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 4.1   4.1   9.9            
Less: funded commitments (0.2)   (0.2)   0.0            
Total unfunded commitments 3.9   3.9   9.9            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 3.9   $ 3.9   $ 9.9            
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.30% [2]   9.30% [2]   6.75% [1] 9.30% [2] 9.30% [2] 9.30% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 18.0 [3],[4]   $ 18.0 [3],[4]   $ 18.2 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 18.0 [3],[4]   $ 18.0 [3],[4]   $ 18.2 [6]            
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.91% [2]   8.91% [2]   6.75% [1] 8.91% [2] 8.91% [2] 8.91% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.2 [3],[4]   $ 0.2 [3],[4]   $ 9.5 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.2 [3],[4]   $ 0.2 [3],[4]   9.5 [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 [2] 9.38%   9.38%     9.38% 9.38% 9.38%      
Total first lien senior secured loans [3],[4] $ 0.2   $ 0.2                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 0.2   0.2                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [15] 0.0   0.0                
Investment, Identifier [Axis]: Wildcat BuyerCo, Inc. and Wildcat Parent, LP, Limited partnership interests                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 4.7 [4]   $ 4.7 [4]   $ 2.8 [7]            
Investment, Identifier [Axis]: Winebow Holdings, Inc. and The Vintner Group, Inc., First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 9.37% [2]   9.37% [2]   7.25% [1] 9.37% [2] 9.37% [2] 9.37% [2] 7.25% [1] 7.25% [1] 7.25% [1]
Total first lien senior secured loans $ 28.1 [3],[4]   $ 28.1 [3],[4]   $ 28.3 [6]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 27.8 [3],[4]   27.8 [3],[4]   28.3 [6]            
Investment, Identifier [Axis]: WorkWave Intermediate II, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 22.6   22.6   5.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 22.6   22.6   5.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 22.6   $ 22.6   5.2            
Investment, Identifier [Axis]: WorkWave Intermediate II, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.90%   10.90%     10.90% 10.90% 10.90%      
Total first lien senior secured loans $ 65.6 [3],[4]   $ 65.6 [3],[4]   61.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 65.6 [3],[4]   65.6 [3],[4]   61.6 [6],[7]            
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 8.9   8.9   8.9            
Less: funded commitments (0.2)   (0.2)   (1.1)            
Total unfunded commitments 8.7   8.7   7.8            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 8.7   8.7   7.8            
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, Class A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 4.5 [4]   4.5 [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]                      
Total investments at fair value $ 1.2 [4]   $ 1.2 [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 8.87% [2]   8.87% [2]   6.75% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 37.1 [3]   $ 37.1 [3]   $ 16.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 36.7 [3]   $ 36.7 [3]   $ 16.1 [6],[7]            
Investment, Identifier [Axis]: XIFIN, Inc. and ACP Charger Co-Invest LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 8.87% [2]   8.87% [2]   6.75% [1] 8.87% [2] 8.87% [2] 8.87% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 39.3 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 0.1 [3],[4]   $ 0.1 [3],[4]   $ 39.0 [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 11.00% [2]   11.00% [2]   6.75% [1] 11.00% [2] 11.00% [2] 11.00% [2] 6.75% [1] 6.75% [1] 6.75% [1]
Total first lien senior secured loans $ 0.2 [3]   $ 0.2 [3]   $ 1.1 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 0.2 [3]   0.2 [3]   1.1 [6],[7]            
Investment, Identifier [Axis]: YE Brands Holdings, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.2   2.2   1.2            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.2   2.2   1.2            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 2.2   $ 2.2   $ 1.2            
Investment, Identifier [Axis]: YE Brands Holdings, LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate 7.96% [2]   7.96% [2]   6.25% [1] 7.96% [2] 7.96% [2] 7.96% [2] 6.25% [1] 6.25% [1] 6.25% [1]
Total first lien senior secured loans $ 8.2 [3],[4]   $ 8.2 [3],[4]   $ 8.0 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 8.1 [3],[4]   $ 8.1 [3],[4]   $ 7.9 [6],[7]            
Investment, Identifier [Axis]: YE Brands Holdings, LLC, First lien senior secured loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 8.97%   8.97%     8.97% 8.97% 8.97%      
Total first lien senior secured loans [3],[4] $ 8.0   $ 8.0                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 7.8   7.8                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 21.5   21.5                
Less: funded commitments (0.1)   (0.1)                
Total unfunded commitments 21.4   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 commitments $ 21.4   $ 21.4                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC, First lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 7.63%   7.63%     7.63% 7.63% 7.63%      
Total first lien senior secured loans [3],[4] $ 1.4   $ 1.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 1.4   1.4                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC, First lien senior secured revolving loan                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [15] 0.0   0.0                
Investment, Identifier [Axis]: ZB Holdco LLC & ZB Parent LLC, Series A units                      
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 5.3   $ 5.3                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         9.00%       9.00% 9.00% 9.00%
Total first lien senior secured loans [6],[7]         $ 56.0            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6],[7]         $ 56.0            
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 1                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.36%   10.36%     10.36% 10.36% 10.36%      
Total first lien senior secured loans [3],[4] $ 55.8   $ 55.8                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 55.2   $ 55.2                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 2                      
Schedule of Investments [Line Items]                      
Coupon | Rate 10.36% [2]   10.36% [2]   9.00% [1] 10.36% [2] 10.36% [2] 10.36% [2] 9.00% [1] 9.00% [1] 9.00% [1]
Total first lien senior secured loans $ 56.0 [3],[4]   $ 56.0 [3],[4]   $ 5.4 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value $ 55.4 [3],[4]   $ 55.4 [3],[4]   5.4 [6],[7]            
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 3                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.36%   10.36%     10.36% 10.36% 10.36%      
Total first lien senior secured loans [3],[4] $ 24.3   $ 24.3                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 24.1   $ 24.1                
Investment, Identifier [Axis]: eCapital Finance Corp., Senior subordinated loan 4                      
Schedule of Investments [Line Items]                      
Coupon | Rate [2] 10.36%   10.36%     10.36% 10.36% 10.36%      
Total first lien senior secured loans [3],[4] $ 5.4   $ 5.4                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] 5.3   5.3                
Investment, Identifier [Axis]: eResearch Technology, Inc. and Astorg VII Co-Invest ERT | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 2.5   2.5   2.5            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 2.5   2.5   2.5            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments 2.5   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]                      
Total investments at fair value $ 3.2 [4],[5]   $ 3.2 [4],[5]   $ 5.4 [7],[8]            
Investment, Identifier [Axis]: eResearch Technology, Inc. and Astorg VII Co-Invest ERT, Second lien senior secured loan                      
Schedule of Investments [Line Items]                      
Coupon | Rate [1]         8.50%       8.50% 8.50% 8.50%
Total first lien senior secured loans [6]         $ 22.5            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [6]         $ 22.4            
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 [2] 11.12%   11.12%     11.12% 11.12% 11.12%      
Total first lien senior secured loans [3],[4] $ 30.6   $ 30.6                
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value [3],[4] $ 29.1   $ 29.1                
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 11.12% [2]   11.12% [2]   8.50% [1] 11.12% [2] 11.12% [2] 11.12% [2] 8.50% [1] 8.50% [1] 8.50% [1]
Total first lien senior secured loans $ 17.2 [3],[4]   $ 17.2 [3],[4]   $ 30.6 [6],[7]            
Investments Activity And Fair Value Table [Abstract]                      
Total investments at fair value 16.3 [3],[4]   16.3 [3],[4]   30.6 [6],[7]            
Investment, Identifier [Axis]: n2y Holding, LLC | Revolving and delayed draw loan commitments                      
Financial Support for Nonconsolidated Legal Entity [Abstract]                      
Total commitments 0.1   0.1   0.1            
Less: funded commitments 0.0   0.0   0.0            
Total unfunded commitments 0.1   0.1   0.1            
Less: commitments substantially at discretion of the Company 0.0   0.0   0.0            
Less: unavailable commitments due to borrowing base or other covenant restrictions 0.0   0.0   0.0            
Total net adjusted unfunded revolving and delayed draw commitments $ 0.1   $ 0.1   $ 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 facility (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, 23% of the Company's total assets are represented by investments at fair value and other assets that are considered "non-qualifying assets" as of September 30, 2022.
[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 facility (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, 16% 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, 2021.
[9] Loan was on non-accrual status as of September 30, 2022.
[10] Loan was on non-accrual status as of December 31, 2021.
[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 September 30, 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.
[14] As of December 31, 2021, 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 September 30, 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 December 31, 2021, 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 $79.3 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 $79.3 secured borrowing, at fair value, included in “secured borrowings” in the accompanying consolidated balance sheet. As of September 30, 2022, the interest rate in effect for the secured borrowing was 10.06%.
[18] The Company sold a participating interest of approximately $75.0 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 GAAP, the Company recorded a corresponding $73.2 secured borrowing, at fair value, included in “secured borrowings” in the accompanying consolidated balance sheet. As of December 31, 2021, the interest rate in effect for the secured borrowing was 8.50%.
[19] As of December 31, 2021, the Company was party to subscription agreements to fund equity investments in private equity investment partnerships as follows:
(in millions)
Company		Total private equity commitmentsLess: funded private equity commitmentsTotal unfunded private equity commitmentsLess: private equity commitments substantially at the discretion of the CompanyTotal net adjusted unfunded private equity commitments
PCG-Ares Sidecar Investment, L.P. and PCG-Ares Sidecar Investment II, L.P.$50.0 $(12.5)$37.5 $(37.5)$— 
European Capital UK SME Debt LP60.9 (55.1)5.8 (5.8)— 
$110.9 $(67.6)$43.3 $(43.3)$— 
[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 interest rate of this security, the Company is entitled to receive an additional interest amount of 2.00% on $46.9 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.