Fair Value of Investments - Changes in Fair Value of Level 3 Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Jul. 28, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset acquisition, investments, fair value		$ 186,300
AG Twin Brook BDC, Inc.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset acquisition, investments, fair value			$ 186,264
Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1,343,705	797,019
Purchases and Drawdowns	2,243,761	704,942
Sales and Paydowns	(522,943)	(162,560)
Other	19,411	6,584
Ending balance	3,080,569	1,343,705
Change in Unrealized Appreciation/(Depreciation) for Level 3 Assets Still Held	(4,050)	(2,171)
Investments | Realized Gains/ (Losses)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	6	(11)
Investments | Change in Unrealized Appreciation/(Depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Gains (losses) included in earnings	(3,371)	(2,269)
First lien senior secured debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1,343,692	797,019
Purchases and Drawdowns	2,243,761	704,930
Sales and Paydowns	(522,943)	(162,560)
Other	19,410	6,584
Ending balance	3,080,554	1,343,692
Change in Unrealized Appreciation/(Depreciation) for Level 3 Assets Still Held	(4,051)	(2,172)
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	6	(11)
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	(3,372)	(2,270)
Sponsor subordinated note
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	13	0
Purchases and Drawdowns	0	12
Sales and Paydowns	0	0
Other	1	0
Ending balance	15	13
Change in Unrealized Appreciation/(Depreciation) for Level 3 Assets Still Held	1	1
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
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	$ 1	$ 1