v3.26.1
INVESTMENTS - Schedule of Composition of Investment Portfolio at Cost And Fair Value (Details) - USD ($)
$ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Cost $ 2,500,365 $ 2,424,280
Fair Value $ 2,458,590 $ 2,398,524
Percentage of Total Net Assets 214.60% [1] 206.60% [2]
Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Cost $ 1,186,491 $ 1,290,521
Fair Value 1,126,044 1,241,387
Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Cost 71,403 118,200
Fair Value $ 65,620 111,752
Sierra JV    
Schedule of Investments [Line Items]    
Cost   2,721
Fair Value   $ 2,701
Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%
Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%
Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%
Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Sierra JV    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio   100.00%
Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%
Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%
Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%
Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Sierra JV    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio   100.00%
Senior debt and 1st lien notes    
Schedule of Investments [Line Items]    
Cost $ 1,768,638 $ 1,704,910
Fair Value $ 1,725,708 $ 1,676,334
Percentage of Total Net Assets 151.00% 144.00%
Senior debt and 1st lien notes | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Cost $ 1,113,703 $ 1,226,601
Fair Value $ 1,077,265 1,202,376
Senior debt and 1st lien notes | Sierra JV    
Schedule of Investments [Line Items]    
Cost   2,721
Fair Value   $ 2,701
Senior debt and 1st lien notes | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 71.00% 70.00%
Senior debt and 1st lien notes | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 94.00% 95.00%
Senior debt and 1st lien notes | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Sierra JV    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio   100.00%
Senior debt and 1st lien notes | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 70.00% 70.00%
Senior debt and 1st lien notes | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 96.00% 97.00%
Senior debt and 1st lien notes | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Sierra JV    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio   100.00%
Subordinated debt and 2nd lien notes    
Schedule of Investments [Line Items]    
Cost $ 236,879 $ 195,392
Fair Value $ 234,415 $ 190,290
Percentage of Total Net Assets 21.00% 17.00%
Subordinated debt and 2nd lien notes | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Cost $ 14,399 $ 10,561
Fair Value $ 14,706 $ 10,594
Subordinated debt and 2nd lien notes | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 9.00% 8.00%
Subordinated debt and 2nd lien notes | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 1.00% 1.00%
Subordinated debt and 2nd lien notes | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 10.00% 8.00%
Subordinated debt and 2nd lien notes | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 2.00% 1.00%
Structured products    
Schedule of Investments [Line Items]    
Cost $ 26,019 $ 39,462
Fair Value $ 24,201 $ 29,627
Percentage of Total Net Assets 2.00% 3.00%
Structured products | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 1.00% 2.00%
Structured products | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 1.00% 1.00%
Equity shares    
Schedule of Investments [Line Items]    
Cost $ 389,739 $ 382,930
Fair Value $ 435,572 $ 436,466
Percentage of Total Net Assets 38.00% 38.00%
Equity shares | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Cost $ 4,593 $ 874
Fair Value $ 4,703 362
Equity shares | Sierra JV    
Schedule of Investments [Line Items]    
Cost   0
Fair Value   $ 0
Equity shares | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 16.00% 16.00%
Equity shares | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Equity shares | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Sierra JV    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio   0.00%
Equity shares | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 18.00% 18.00%
Equity shares | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Equity shares | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Sierra JV    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio   0.00%
Equity warrants    
Schedule of Investments [Line Items]    
Cost $ 76 $ 76
Fair Value $ 1,267 $ 1,170
Percentage of Total Net Assets 0.00% 0.00%
Equity warrants | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Equity warrants | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Royalty rights    
Schedule of Investments [Line Items]    
Cost $ 1,237 $ 1,292
Fair Value $ 1,459 $ 1,486
Percentage of Total Net Assets 0.00% 0.00%
Royalty rights | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Royalty rights | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Investment in joint ventures    
Schedule of Investments [Line Items]    
Cost $ 77,777 $ 100,218
Fair Value $ 35,968 $ 63,151
Percentage of Total Net Assets 3.00% 5.00%
Investment in joint ventures | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Cost $ 28,149 $ 34,704
Fair Value $ 3,723 $ 10,274
Investment in joint ventures | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 3.00% 4.00%
Investment in joint ventures | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 3.00% 3.00%
Investment in joint ventures | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 1.00% 3.00%
Investment in joint ventures | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 1.00%
Short-term investments | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Cost $ 25,647 $ 17,781
Fair Value $ 25,647 $ 17,781
Short-term investments | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 2.00% 1.00%
Short-term investments | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Jocassee Partners LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 2.00% 1.00%
Federal Housing Administration (“FHA”) loans | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Cost $ 68,543 $ 112,317
Fair Value $ 63,005 $ 106,195
Federal Housing Administration (“FHA”) loans | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 96.00% 95.00%
Federal Housing Administration (“FHA”) loans | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 96.00% 95.00%
Veterans Affairs (“VA”) loans | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Cost $ 2,860 $ 5,883
Fair Value $ 2,615 $ 5,557
Veterans Affairs (“VA”) loans | Percentage of Total Portfolio, at Cost | Investment Type Concentration Risk | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 4.00% 5.00%
Veterans Affairs (“VA”) loans | Percentage of Total Portfolio, at Fair Value | Investment Type Concentration Risk | Thompson Rivers LLC    
Schedule of Investments [Line Items]    
Percentage of Total Portfolio 4.00% 5.00%
[1] Fair value as a percentage of net assets.
[2] Fair value as a percentage of net assets.