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Fair Value - Schedule of Changes in Fair Value of Level III Portfolio Investments (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Total |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | $ 2,920,263 | $ 3,098,192 | $ 2,987,078 | $ 2,938,849
Purchases, including capitalized PIK and revolver fundings | 139,332 | 170,005 | 470,593 | 797,225
Proceeds from sales and paydowns of investments | (163,342) | (110,879) | (550,437) | (608,697)
Transfers into Level III | 20,231 |  | 29,666 | 28,440
Transfers out of Level III | (54,257) | (8,931) | (46,430) |
Ending balance | 2,842,734 | 3,141,885 | 2,842,734 | 3,141,885
Net change in unrealized (depreciation) appreciation for the period relating to those Level III assets that were still held by the Company at the end of the period: | (37,652) | (6,029) | (53,505) | (23,625)
Total | Net realized gains (loss) on investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 11 | (1,981) | 51,087 | (44,979)
Total | Net change in unrealized (depreciation) appreciation of investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | (19,504) | (4,521) | (98,823) | 31,047
First lien |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 1,927,366 | 1,973,080 | 1,902,610 | 1,637,889
Purchases, including capitalized PIK and revolver fundings | 121,173 | 136,054 | 365,524 | 708,021
Proceeds from sales and paydowns of investments | (98,831) | (83,124) | (319,690) | (360,253)
Transfers into Level III | 0 |  | 0 | 28,440
Transfers out of Level III | (54,257) | (8,931) | (46,430) |
Ending balance | 1,888,377 | 2,019,063 | 1,888,377 | 2,019,063
Net change in unrealized (depreciation) appreciation for the period relating to those Level III assets that were still held by the Company at the end of the period: | (7,387) | 2,007 | (13,964) | 3,908
First lien | Net realized gains (loss) on investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 3 | (1,529) | 101 | (13,267)
First lien | Net change in unrealized (depreciation) appreciation of investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | (7,077) | 3,513 | (13,738) | 18,233
Second lien |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 128,623 | 216,064 | 150,334 | 406,180
Purchases, including capitalized PIK and revolver fundings | 9,464 | 1,485 | 13,719 | 13,546
Proceeds from sales and paydowns of investments | (62,656) | (25,766) | (94,270) | (233,648)
Transfers into Level III | 20,231 |  | 26,434 | 0
Transfers out of Level III | 0 | 0 | 0 |
Ending balance | 98,128 | 191,332 | 98,128 | 191,332
Net change in unrealized (depreciation) appreciation for the period relating to those Level III assets that were still held by the Company at the end of the period: | 2,498 | (452) | 4,386 | 347
Second lien | Net realized gains (loss) on investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | (33) | 0 | (2,762) | (35,163)
Second lien | Net change in unrealized (depreciation) appreciation of investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 2,499 | (451) | 4,673 | 40,417
Subordinated |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 107,986 | 96,653 | 102,034 | 82,871
Purchases, including capitalized PIK and revolver fundings | 3,187 | 2,823 | 8,965 | 18,044
Proceeds from sales and paydowns of investments | 0 | (292) | 0 | (292)
Transfers into Level III | 0 |  | 0 | 0
Transfers out of Level III | 0 | 0 | 0 |
Ending balance | 111,031 | 99,386 | 111,031 | 99,386
Net change in unrealized (depreciation) appreciation for the period relating to those Level III assets that were still held by the Company at the end of the period: | (143) | 197 | 30 | (1,242)
Subordinated | Net realized gains (loss) on investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 0 | 3 | 0 | 3
Subordinated | Net change in unrealized (depreciation) appreciation of investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | (142) | 199 | 32 | (1,240)
Structured Finance Obligations |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 3,249 |  | 0 |
Purchases, including capitalized PIK and revolver fundings | 0 |  | 0 |
Proceeds from sales and paydowns of investments | 0 |  | 0 |
Transfers into Level III | 0 |  | 3,232 |
Transfers out of Level III | 0 |  | 0 |
Ending balance | 3,257 |  | 3,257 |
Net change in unrealized (depreciation) appreciation for the period relating to those Level III assets that were still held by the Company at the end of the period: | 8 |  | 25 |
Structured Finance Obligations | Net realized gains (loss) on investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 0 |  | 0 |
Structured Finance Obligations | Net change in unrealized (depreciation) appreciation of investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 8 |  | 25 |
Equity and other |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 753,039 | 812,395 | 832,100 | 811,909
Purchases, including capitalized PIK and revolver fundings | 5,508 | 29,643 | 82,385 | 57,614
Proceeds from sales and paydowns of investments | (1,855) | (1,697) | (136,477) | (14,504)
Transfers into Level III | 0 |  | 0 | 0
Transfers out of Level III | 0 | 0 | 0 |
Ending balance | 741,941 | 832,104 | 741,941 | 832,104
Net change in unrealized (depreciation) appreciation for the period relating to those Level III assets that were still held by the Company at the end of the period: | (32,628) | (7,781) | (43,982) | (26,638)
Equity and other | Net realized gains (loss) on investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | 41 | (455) | 53,748 | 3,448
Equity and other | Net change in unrealized (depreciation) appreciation of investments |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Total gains or losses included in earnings: | $ (14,792) | $ (7,782) | $ (89,815) | $ (26,363)

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