v3.26.1
Investments - Schedule of Changes in Fair Value of Investments (Detail) - Level 3 - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Schedule of Investments [Line Items]        
Fair value, Beginning balance $ 2,928,455 $ 3,107,791 $ 3,114,898 $ 2,894,850
Net realized gains (losses) (1,693) (14,727) (5,236) (11,322)
Net change in unrealized gains (losses) (46,862) 724 (98,084) (4,667)
Net amortization on investments 961 1,555 2,337 3,291
Purchases, including capitalized PIK 129,138 [1] 293,928 [2] 234,351 [3] 685,470 [4]
Sales (281,762) [1] (139,382) [2] (516,482) [3] (311,370) [4]
Transfers out of Level 3 0 [5] (270) [6] (161) [7] (6,633) [8]
Transfers into Level 3 0 [5]   0 [7]  
Fair value, Ending balance 2,731,623 3,249,619 2,731,623 3,249,619
Net change in unrealized gains (losses) on Level 3 investments still held (66,885) (12,547) (119,796) (14,703)
First Lien Secured Debt        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 2,782,520 [9] 2,896,724 [10] 2,951,423 [11] 2,676,253 [12]
Net realized gains (losses) 1,693 [9] (9,558) [10] (75) [11] (8,132) [12]
Net change in unrealized gains (losses) (12,057) [9] (3,715) [10] (56,038) [11] (5,813) [12]
Net amortization on investments 961 [9] 1,555 [10] 2,355 [11] 3,291 [12]
Purchases, including capitalized PIK 52,277 [1],[9] 288,749 [2],[10] 157,343 [3],[11] 679,489 [4],[12]
Sales (268,980) [9] (137,670) [2],[10] (498,594) [3],[11] (302,640) [4],[12]
Transfers out of Level 3   (270) [6],[10]   (6,633) [8],[12]
Transfers into Level 3 0 [5]   0 [7],[11]  
Fair value, Ending balance 2,556,414 [9] 3,035,815 [10],[12] 2,556,414 [9] 3,035,815 [10],[12]
Net change in unrealized gains (losses) on Level 3 investments still held (32,289) [9] (11,672) [10] (72,762) [11] (11,490) [12]
Second Lien Secured Debt        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 51 [9] 4,221 [10] 62 [11] 5,764 [12]
Net realized gains (losses) 0 [9] (2,501) [10] 0 [11] (2,501) [12]
Net change in unrealized gains (losses) (0) [9] (1,167) [10] 7 [11] (2,716) [12]
Net amortization on investments 0 [9]   (18) [11]  
Purchases, including capitalized PIK 0 [1],[9] 3 [2],[10] 0 [3],[11] 9 [4],[12]
Sales 0 [9] (481) [2],[10] 0 [3],[11] (481) [4],[12]
Fair value, Ending balance 51 [9] 75 [10],[12] 51 [9] 75 [10],[12]
Net change in unrealized gains (losses) on Level 3 investments still held 212 [9] (3,927) [10] 230 [11] (7,705) [12]
Unsecured Debt        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 1,842 109 1,842 117
Net realized gains (losses)   (2,672) 0 (2,672)
Net change in unrealized gains (losses) 0 2,584 0 2,576
Purchases, including capitalized PIK 0 [1] 0 [2] 0 [3] 0 [4]
Sales   0 [2] 0 [3] 0 [4]
Fair value, Ending balance 1,842 21 1,842 21
Net change in unrealized gains (losses) on Level 3 investments still held 0 0 0 0
Structured Products And Other        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 16,585 23,492 18,350 26,101
Net realized gains (losses)   0 0 0
Net change in unrealized gains (losses) (1,393) (1,025) (2,239) (1,456)
Purchases, including capitalized PIK 26 [1] 152 [2] 107 [3] 152 [4]
Sales (278) [1] (1,020) [2] (1,278) [3] (3,198) [4]
Fair value, Ending balance 14,940 21,599 14,940 21,599
Net change in unrealized gains (losses) on Level 3 investments still held (1,393) (1,025) (2,239) (1,456)
Preferred Equity        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 18,612 23,664 27,104 24,831
Net realized gains (losses) 0 0 (4,344) 0
Net change in unrealized gains (losses) (32,554) (4,218) (36,757) (5,235)
Purchases, including capitalized PIK 76,835 [1] 4,449 [2] 76,890 [3] 4,549 [4]
Sales 0 [1] 0 [2] 0 [3] (250) [4]
Fair value, Ending balance 62,893 23,895 62,893 23,895
Net change in unrealized gains (losses) on Level 3 investments still held (32,569) (4,215) (41,119) (5,235)
Common Equity/Interests        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 108,712 159,366 115,791 161,648
Net realized gains (losses) 0 4 (817) 1,983
Net change in unrealized gains (losses) (859) 8,318 (2,865) 7,951
Purchases, including capitalized PIK 0 [1] 575 [2] 11 [3] 1,271 [4]
Sales (12,504) [1] (211) [2] (16,610) [3] (4,801) [4]
Transfers out of Level 3 0 [5]   (161) [7]  
Fair value, Ending balance 95,349 168,052 95,349 168,052
Net change in unrealized gains (losses) on Level 3 investments still held (848) 8,345 (3,715) 11,157
Warrants - Warrants        
Schedule of Investments [Line Items]        
Fair value, Beginning balance 133 215 326 136
Net realized gains (losses) 0 0 0 0
Net change in unrealized gains (losses) 1 (53) (192) 26
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 134 162 134 162
Net change in unrealized gains (losses) on Level 3 investments still held $ (1) $ (54) $ (192) $ 26
[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 $(9,052).
[10] Includes unfunded commitments measured at fair value of $(7,018).
[11] Includes unfunded commitments measured at fair value of $(9,052).
[12] Includes unfunded commitments measured at fair value of $(7,018).