v3.26.3
INVESTMENTS - Jocassee Partners LLC (Details) - USD ($)
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
May 08, 2019
May 07, 2019
Schedule of Investments [Line Items]              
Committed investment amount $ 462,018,000   $ 462,018,000   $ 400,635,000    
Total dividend income 11,372,000 $ 14,177,000 37,298,000 $ 39,512,000      
Fair value 2,509,771,000   2,509,771,000   2,398,524,000    
Cost 2,552,012,000   2,552,012,000   2,424,280,000    
Borrowings under credit facility 334,732,000   334,732,000   226,786,000    
Repayments received / sales of portfolio investments     493,021,000 425,436,000      
Jocassee Partners LLC              
Schedule of Investments [Line Items]              
Repayments received / sales of portfolio investments 0   1,355,500,000   1,303,700,000    
Loss on sale of investments     100,000        
Due from related parties 0   0   52,000,000.0    
Jocassee Partners LLC | Subscription Facility | Bank Of America Subscription Facility | Line of Credit              
Schedule of Investments [Line Items]              
Borrowings under credit facility 180,300,000   180,300,000   182,900,000    
Jocassee Partners LLC | Subscription Facility | Citibank N.A. Subscription Facility | Line of Credit              
Schedule of Investments [Line Items]              
Borrowings under credit facility 299,300,000   299,300,000   328,500,000    
Jocassee Partners LLC | Subscription Facility | Term Debt Securitization | Line of Credit              
Schedule of Investments [Line Items]              
Borrowings under credit facility 414,900,000   414,900,000   323,900,000    
Jocassee Partners LLC              
Schedule of Investments [Line Items]              
Dividends 31,400,000 15,700,000 94,200,000 47,100,000      
Total dividend income 2,900,000 $ 1,400,000 8,600,000 $ 4,300,000      
Fair value 1,231,039,000   1,231,039,000   1,241,387,000    
Cost 1,284,076,000   $ 1,284,076,000   $ 1,290,521,000    
Interest-earning assets, average yield     8.20%   8.30%    
Jocassee Partners LLC | Long-Term Investments              
Schedule of Investments [Line Items]              
Fair value 1,231,000,000   $ 1,231,000,000   $ 1,241,400,000    
Cost $ 1,284,100,000   $ 1,284,100,000   $ 1,290,500,000    
Jocassee Partners LLC | SCRS              
Schedule of Investments [Line Items]              
Committed investment amount           $ 500,000,000.0 $ 100,000,000.0