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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ 4,274,058	$ 1,262,452	$ 3,096,465	$ 808,801
Purchases or originations	995,734	523,565	2,293,820	968,327
Repayments / redemptions	(30,579)	(32,451)	(41,602)	(38,737)
Sales proceeds	(268,010)		(408,569)
Paid-in-kind interest	8,200	779	13,745	799
Net change in unrealized gains (losses)	16,110	$ 872	34,624	$ 14,633
Net realized gains (losses)	$ 1,570		$ 4,412
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Change In Unrealized Gains Losses On Investments And Foreign Currency Translation	Net Change In Unrealized Gains Losses On Investments And Foreign Currency Translation	Net Change In Unrealized Gains Losses On Investments And Foreign Currency Translation	Net Change In Unrealized Gains Losses On Investments And Foreign Currency Translation
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Realized Gains Losses on Investments and Foreign Currency Translation	Net Realized Gains Losses on Investments and Foreign Currency Translation	Net Realized Gains Losses on Investments and Foreign Currency Translation	Net Realized Gains Losses on Investments and Foreign Currency Translation
Net amortization of discount on securities	$ 4,710	$ 3,694	$ 8,898	$ 5,088
Balance, End of Period	5,001,793	1,758,911	5,001,793	1,758,911
First-lien Debt Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	3,979,498	1,246,008	2,848,805	800,995
Purchases or originations	995,734	422,327	2,255,540	858,451
Repayments / redemptions	(30,579)	(32,451)	(41,602)	(38,737)
Sales proceeds	(265,850)		(406,408)
Paid-in-kind interest	4,306	779	6,591	799
Net change in unrealized gains (losses)	13,328	203	26,783	13,964
Net realized gains (losses)	1,504		4,346
Net amortization of discount on securities	4,383	3,613	8,269	5,007
Balance, End of Period	4,702,324	1,640,479	4,702,324	1,640,479
Second-lien Debt Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	89,086		79,091
Purchases or originations			10,021
Sales proceeds	(2,160)		(2,161)
Paid-in-kind interest	494		494
Net change in unrealized gains (losses)	2,586		2,359
Net realized gains (losses)	66		66
Net amortization of discount on securities	227		429
Balance, End of Period	90,299		90,299
Mezzanine Debt Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	111,081		105,918
Purchases or originations		97,000		97,000
Paid-in-kind interest	3,400		6,660
Net change in unrealized gains (losses)	509	669	2,312	669
Net amortization of discount on securities	100	81	200	81
Balance, End of Period	115,090	97,750	115,090	97,750
Equity and Other Investments
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	94,393	16,444	62,651	7,806
Purchases or originations		4,238	28,259	12,876
Net change in unrealized gains (losses)	(313)		3,170
Balance, End of Period	$ 94,080	$ 20,682	$ 94,080	$ 20,682