Fair Value of Financial Instruments - Changes in Fair Value of Investments Using Level 3 Inputs (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||||
| Balance, beginning of period | $ 8,435,390 | $ 7,176,460 | $ 7,847,447 | $ 7,099,575 |
| Purchases or originations | 476,904 | 382,988 | 1,416,950 | 1,159,199 |
| Repayments / redemptions | (482,370) | (458,687) | (684,461) | (1,099,011) |
| Sales proceeds | (17,422) | (3,088) | (127,182) | |
| Paid-in-kind interest | 14,346 | 15,811 | 31,341 | 29,885 |
| Net change in unrealized gains (losses) | 1,472 | 117,267 | (170,828) | 138,244 |
| Net realized gains (losses) | $ 15 | $ 7,214 | $ 49 | $ 7,674 |
| Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax | Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax | Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax | Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax |
| Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Realized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax | Realized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax | Realized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax | Realized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax |
| Net amortization of discount on securities | $ 8,587 | $ 16,736 | $ 16,934 | $ 31,983 |
| Balance, End of Period | 8,454,344 | 7,240,367 | 8,454,344 | 7,240,367 |
| First-lien Debt Investments | ||||
| Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||||
| Balance, beginning of period | 8,001,078 | 6,686,427 | 7,398,928 | 6,728,411 |
| Purchases or originations | 458,535 | 382,321 | 1,391,246 | 1,059,498 |
| Repayments / redemptions | (482,370) | (374,771) | (684,461) | (1,015,095) |
| Sales proceeds | (5,659) | (3,088) | (115,419) | |
| Paid-in-kind interest | 6,648 | 10,390 | 15,939 | 20,009 |
| Net change in unrealized gains (losses) | (8,418) | 128,445 | (151,174) | 134,497 |
| Net realized gains (losses) | 15 | 26 | 49 | 486 |
| Net amortization of discount on securities | 8,282 | 11,530 | 16,331 | 26,322 |
| Balance, End of Period | 7,983,770 | 6,838,709 | 7,983,770 | 6,838,709 |
| Second-lien Debt Investments | ||||
| Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||||
| Balance, beginning of period | 37,210 | 121,036 | 37,160 | 93,469 |
| Purchases or originations | 19,198 | |||
| Repayments / redemptions | (83,916) | (83,916) | ||
| Paid-in-kind interest | 1,418 | 1,229 | 2,772 | 2,167 |
| Net change in unrealized gains (losses) | (220) | (11,140) | (1,682) | (4,055) |
| Net amortization of discount on securities | 163 | 5,056 | 321 | 5,402 |
| Balance, End of Period | 38,571 | 32,265 | 38,571 | 32,265 |
| Mezzanine Debt Investments | ||||
| Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||||
| Balance, beginning of period | 225,454 | 204,815 | 222,366 | 123,184 |
| Purchases or originations | 76,440 | |||
| Paid-in-kind interest | 6,280 | 4,192 | 12,630 | 7,709 |
| Net change in unrealized gains (losses) | (1,282) | 935 | (4,684) | 2,500 |
| Net amortization of discount on securities | 142 | 150 | 282 | 259 |
| Balance, End of Period | 230,594 | 210,092 | 230,594 | 210,092 |
| Equity Investments | ||||
| Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||||
| Balance, beginning of period | 164,313 | 164,182 | 188,993 | 154,511 |
| Purchases or originations | 667 | 4,063 | ||
| Sales proceeds | (11,763) | (11,763) | ||
| Net change in unrealized gains (losses) | 10,171 | (973) | (14,509) | 5,302 |
| Net realized gains (losses) | 7,188 | 7,188 | ||
| Balance, End of Period | 174,484 | $ 159,301 | 174,484 | $ 159,301 |
| Joint Venture Investments | ||||
| Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||||
| Balance, beginning of period | 7,335 | |||
| Purchases or originations | 18,369 | 25,704 | ||
| Net change in unrealized gains (losses) | 1,221 | 1,221 | ||
| Balance, End of Period | $ 26,925 | $ 26,925 | ||