v3.26.3
Investments - Schedule of Changes in Fair Value of Investments (Detail) - Level 3 - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Schedule of Investments [Line Items]        
Fair value, Beginning balance $ 2,731,623 $ 3,249,619 $ 3,114,898 $ 2,894,850
Net realized gains (losses) (24,931) (15,979) (30,066) (27,318)
Net change in unrealized gains (losses) (13,799) 10,017 (111,883) 5,503
Net amortization on investments 1,340 2,225 3,651 5,470
Purchases, including capitalized PIK 38,926 [1] 401,822 [2] 273,505 [3] 1,090,411 [4]
Sales (203,651) [1] (529,116) [2] (720,436) [3] (843,569) [4]
Transfers out of Level 3 0 [5] 0 [6] (161) [7] (69) [8]
Transfers into Level 3 41 [5] 6,690 [5] 41 [7]  
Fair value, Ending balance 2,529,549 3,125,278 2,529,549 3,125,278
Net change in unrealized gains (losses) on Level 3 investments still held (43,039) (8,485) (154,859) (17,727)
First Lien Secured Debt        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 2,556,414 [9] 3,035,815 [10] 2,951,423 [11] 2,676,253 [12]
Net realized gains (losses) (16,569) [9] (4,974) [10] (16,543) [11] (13,123) [12]
Net change in unrealized gains (losses) 1,620 [9] (16,191) [10] (54,418) [11] (21,851) [12]
Net amortization on investments 1,335 [9] 2,225 [10] 3,663 [11] 5,470 [12]
Purchases, including capitalized PIK 38,559 [1],[9] 165,541 [2],[10] 196,036 [3],[11] 848,147 [4],[12]
Sales (174,513) [1],[9] (228,952) [2],[10] (673,315) [3],[11] (534,673) [4],[12]
Transfers out of Level 3   0 [6],[10]   (69) [8],[12]
Transfers into Level 3 41 [5],[9] 6,690 [5],[10] 41 [7],[11]  
Fair value, Ending balance 2,406,887 [9] 2,960,154 [10] 2,406,887 [9] 2,960,154 [10]
Net change in unrealized gains (losses) on Level 3 investments still held (19,162) [9] (23,185) [10] (83,647) [11] (28,622) [12]
Second Lien Secured Debt        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 51 [9] 75 [10] 62 [11] 5,764 [12]
Net realized gains (losses) (7,499) [9] 198 [10] (7,499) [11] (2,303) [12]
Net change in unrealized gains (losses) 7,688 [9] (8) [10] 7,694 [11] (2,724) [12]
Net amortization on investments 5 [9]   (12) [11]  
Purchases, including capitalized PIK 0 [1],[9] 5 [2],[10] 95 [3],[11] 14 [4],[12]
Sales (193) [1],[9] (198) [2],[10] (288) [3],[11] (679) [4],[12]
Fair value, Ending balance 52 [9] 72 [10] 52 [9] 72 [10]
Net change in unrealized gains (losses) on Level 3 investments still held 2 [9] 261 [10] (40) [11] (7,705) [12]
Unsecured Debt        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 1,842 21 1,842 117
Net realized gains (losses)   (0) 0 (2,672)
Net change in unrealized gains (losses) (1,847) 0 (1,847) 2,576
Purchases, including capitalized PIK 5 [1] 0 [2] 5 [3] 0 [4]
Sales   0 [2] 0 [3] 0 [4]
Fair value, Ending balance 0 21 0 21
Net change in unrealized gains (losses) on Level 3 investments still held 1,842 0 (1,842) 0
Structured Products And Other        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 14,940 21,599 18,350 26,101
Net realized gains (losses)   0 0 0
Net change in unrealized gains (losses) (5,270) (747) (7,509) (2,202)
Purchases, including capitalized PIK 42 [1] 48 [2] 149 [3] 200 [4]
Sales (1,133) [1] (1,639) [2] (2,411) [3] (4,838) [4]
Fair value, Ending balance 8,579 19,261 8,579 19,261
Net change in unrealized gains (losses) on Level 3 investments still held (5,270) (747) (7,509) (2,202)
Preferred Equity        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 62,893 23,895 27,104 24,831
Net realized gains (losses) 0 0 (4,344) 0
Net change in unrealized gains (losses) (18,603) (1,132) (55,360) (6,367)
Purchases, including capitalized PIK 320 [1] 10,917 [2] 77,210 [3] 15,466 [4]
Sales 0 [1] 0 [2] 0 [3] (250) [4]
Fair value, Ending balance 44,610 33,680 44,610 33,680
Net change in unrealized gains (losses) on Level 3 investments still held (18,603) (1,135) (59,722) (6,368)
Common Equity/Interests        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 95,349 168,052 115,791 161,648
Net realized gains (losses) (863) (10,627) (1,680) (8,644)
Net change in unrealized gains (losses) 2,610 27,460 (254) 35,410
Purchases, including capitalized PIK 0 [1] 225,311 [2] 10 [3] 226,584 [4]
Sales (27,812) [1] (298,327) [2] (44,422) [3] (303,129) [4]
Transfers out of Level 3 0 [5]   (161) [7]  
Fair value, Ending balance 69,284 111,869 69,284 111,869
Net change in unrealized gains (losses) on Level 3 investments still held 1,832 16,261 (1,910) 27,086
Warrants - Warrants        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 134 162 326 136
Net realized gains (losses) 0 (576) 0 (576)
Net change in unrealized gains (losses) 3 635 (189) 661
Purchases, including capitalized PIK   0 [2] 0 [3] 0 [4]
Sales   0 [2] 0 [3] 0 [4]
Transfers out of Level 3 [7]     0  
Fair value, Ending balance 137 221 137 221
Net change in unrealized gains (losses) on Level 3 investments still held $ 3 $ 59 $ (189) $ 85
[1] Includes reorganizations and restructuring of investments.
[2] Includes reorganizations and restructuring of investments.
[3] Includes reorganizations and restructuring of investments.
[4] Includes reorganizations and restructuring of investments.
[5] Transfers out (if any) of Level 3 are due to an increase in the quantity and reliability of broker quotes obtained and transfers into (if any) Level 3 are due to a decrease in the quantity and reliability of broker quotes obtained as assessed by the Investment Adviser. Transfers are assumed to have occurred at the end of the period. There were no transfers between Level 1 and Level 2 fair value measurements during the period shown.
[6] Transfers out (if any) of Level 3 are due to an increase in the quantity and reliability of broker quotes obtained and transfers into (if any) Level 3 are due to a decrease in the quantity and reliability of broker quotes obtained as assessed by the Investment Adviser. Transfers are assumed to have occurred at the end of the period. There were no transfers between Level 1 and Level 2 fair value measurements during the period shown.
[7] Transfers out (if any) of Level 3 are due to an increase in the quantity and reliability of broker quotes obtained and transfers into (if any) Level 3 are due to a decrease in the quantity and reliability of broker quotes obtained as assessed by the Investment Adviser. Transfers are assumed to have occurred at the end of the period. There were no transfers between Level 1 and Level 2 fair value measurements during the period shown.
[8] Transfers out (if any) of Level 3 are due to an increase in the quantity and reliability of broker quotes obtained and transfers into (if any) Level 3 are due to a decrease in the quantity and reliability of broker quotes obtained as assessed by the Investment Adviser. Transfers are assumed to have occurred at the end of the period. There were no transfers between Level 1 and Level 2 fair value measurements during the period shown.
[9] Includes unfunded commitments measured at fair value of $(6,449).
[10] Includes unfunded commitments measured at fair value of $(7,219).
[11] Includes unfunded commitments measured at fair value of $(6,449).
[12] Includes unfunded commitments measured at fair value of $(7,219).