Fair Value of Financial Instruments - Changes in Fair Value of Investments Using Level 3 Inputs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ 7,099,575	$ 3,096,465
Purchases or originations	2,663,075	4,580,038
Repayments / redemptions	(1,945,078)	(313,253)
Sales proceeds	(180,723)	(428,082)
Paid-in-kind interest	69,060	33,624
Net change in unrealized gains (losses)	$ 55,414	$ 101,406
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
Net realized gains (losses)	$ 25,242	$ 4,567
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
Net amortization of discount on securities	$ 60,882	$ 24,810
Balance, End of Period	7,847,447	7,099,575
First-lien Debt Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	6,728,411	2,848,805
Purchases or originations	2,538,463	4,492,641
Repayments / redemptions	(1,861,162)	(313,253)
Sales proceeds	(156,254)	(425,921)
Paid-in-kind interest	43,859	18,092
Net change in unrealized gains (losses)	39,065	80,053
Net realized gains (losses)	11,905	4,501
Net amortization of discount on securities	54,641	23,493
Balance, End of Period	7,398,928	6,728,411
Second-lien Debt Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	93,469	79,091
Purchases or originations	19,198	10,021
Repayments / redemptions	(83,916)
Sales proceeds	0	(2,161)
Paid-in-kind interest	4,788	1,213
Net change in unrealized gains (losses)	(2,080)	4,324
Net realized gains (losses)	0	66
Net amortization of discount on securities	5,701	915
Balance, End of Period	37,160	93,469
Mezzanine Debt Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	123,184	105,918
Purchases or originations	76,440
Paid-in-kind interest	19,773	14,319
Net change in unrealized gains (losses)	2,429	2,545
Net amortization of discount on securities	540	402
Balance, End of Period	222,366	123,184
Equity and Other Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	154,511	62,651
Purchases or originations	28,974	77,376
Sales proceeds	(24,469)
Paid-in-kind interest	640
Net change in unrealized gains (losses)	16,000	14,484
Net realized gains (losses)	13,337
Balance, End of Period	$ 188,993	$ 154,511