Quarterly report pursuant to Section 13 or 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)

v3.24.3
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)
$ in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2024
USD ($)
company
Sep. 30, 2023
company
Sep. 30, 2024
USD ($)
Sep. 30, 2023
Sep. 30, 2024
USD ($)
company
Dec. 31, 2023
USD ($)
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     100.00%     100.00%
Cash equivalents | $ $ 31.2   $ 31.2   $ 31.2 $ 20.8
Cash balances exceeded federal deposit insurance corporation insurance protection levels | $ $ 16.5   $ 16.5   $ 16.5 $ 9.0
Percentage of total investment income, attributable to noncash paid-in-kind interest income (as a percent) 6.70% 4.60% 5.40% 3.90%    
Percentage of total investment income, attributable to noncash cumulative dividend income (as a percent) 0.10% 0.10% 0.10% 0.10%    
Percentage of total investment income, attributable to interest income, debt investments, net (as a percent) 3.00% 2.60% 2.80% 2.60%    
Investment Owned, At Fair Value | Investment Type Concentration Risk            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     100.00%     100.00%
Investment Owned, At Fair Value | Investment Type Concentration Risk | Nonperforming Financial Instruments            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     2.60%     1.10%
Investment Owned, At Cost | Investment Type Concentration Risk            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     100.00%     100.00%
Investment Owned, At Cost | Investment Type Concentration Risk | Nonperforming Financial Instruments            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     6.50%     4.00%
Private Loan portfolio investments            
Schedule of Investments [Line Items]            
Consultation period subsequent to initial investment     12 months      
Investment company, number of portfolio companies with annual third-party appraisal was obtained, reviewed and certified | company 17 14     58  
Percentage of portfolio with annual third-party appraisal was obtained, reviewed and certified (as a percent)         96.00%  
Private Loan portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent) 24.00% 21.00%     78.00%  
LMM portfolio investments            
Schedule of Investments [Line Items]            
Consultation period subsequent to initial investment     12 months      
Investment company, number of portfolio companies with annual third-party appraisal was obtained, reviewed and certified | company 12 12     48  
Percentage of portfolio with annual third-party appraisal was obtained, reviewed and certified (as a percent)         99.00%  
LMM portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent) 22.00% 25.00%     93.00%  
Middle Market portfolio investments            
Schedule of Investments [Line Items]            
Percentage of portfolio investments containing limited consultation with financial advisory services firm (as a percent) 94.00%   94.00%   94.00% 97.00%
Other Portfolio investments | Investment Owned, At Fair Value | Investment Type Concentration Risk            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     2.20%     2.30%
Other Portfolio investments | Investment Owned, At Cost | Investment Type Concentration Risk            
Schedule of Investments [Line Items]            
Concentration risk, percentage (as a percent)     1.70%     2.10%