Fair Value of Investments - Schedule of Changes in Fair Value of Level 3 Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 3,512,536	$ 2,266,894	$ 3,080,569	$ 1,343,705
Purchases and Drawdowns	472,434	582,422	1,155,457	1,634,764
Sales and Paydowns	(176,458)	(154,759)	(439,030)	(290,248)
Other	6,933	5,434	20,467	12,626
Ending balance	3,804,018	2,699,919	3,804,018	2,699,919
Change in Unrealized Appreciation/(Depreciation) for Level 3 Assets Still Held	(14,211)	(441)	(11,717)	(1,527)
Investments | Realized Gains/ (Losses)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	(175)	369	(125)	599
Investments | Change in Unrealized Appreciation/(Depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	(11,252)	(441)	(13,320)	(1,527)
First lien senior secured debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3,512,520	2,266,885	3,080,554	1,343,692
Purchases and Drawdowns	472,035	582,422	1,155,058	1,634,764
Sales and Paydowns	(176,458)	(154,759)	(439,030)	(290,248)
Other	6,933	5,434	20,467	12,625
Ending balance	3,804,000	2,699,909	3,804,000	2,699,909
Change in Unrealized Appreciation/(Depreciation) for Level 3 Assets Still Held	(13,814)	(441)	(11,718)	(1,527)
First lien senior secured debt | Realized Gains/ (Losses)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	(175)	369	(125)	599
First lien senior secured debt | Change in Unrealized Appreciation/(Depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	(10,855)	(442)	(12,924)	(1,523)
Sponsor subordinated note
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	16	9	15	13
Purchases and Drawdowns	399	0	399	0
Sales and Paydowns	0	0	0	0
Other	0	0	0	1
Ending balance	18	10	18	10
Change in Unrealized Appreciation/(Depreciation) for Level 3 Assets Still Held	(397)	0	1	0
Sponsor subordinated note | Realized Gains/ (Losses)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	0	0	0	0
Sponsor subordinated note | Change in Unrealized Appreciation/(Depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	$ (397)	$ 1	$ (396)	$ (4)