Consolidated Statements of Changes in Net Assets - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investment Company, Net Assets [Roll Forward]
Beginning balance (in shares)		107,916,166		65,316,085	107,916,166	65,316,085	65,316,085
Beginning balance		$ 1,192,329		$ 741,931	$ 1,192,329	$ 741,931	$ 717,805
Net investment income	$ 33,371	$ 27,500	$ 36,961	$ 19,009	127,804	115,656	58,960
Net realized(loss) gain on investments / foreign currency transactions / forward currency contracts					(62,750)	12,861	(3,379)
Net unrealized (depreciation) appreciation of investments / CSA / foreign currency transactions					62,624	(123,041)	22,105
Provision for taxes					321	(795)	(1)
Return of capital, merger and other tax related adjustments					0	0	0
Distributions of net investment income					(108,997)	(93,726)	(51,910)
Deemed contribution - from Adviser (See Note 10)						72,130
Issuance of common stock in connection with acquisition of Sierra						499,418
Purchase of shares in repurchase plan					(14,772)	(32,105)
Return of capital distributions					$ 0	$ 0	$ (1,649)
Ending balance (in shares)	106,067,070		107,916,166		106,067,070	107,916,166	65,316,085
Ending balance	$ 1,196,559		$ 1,192,329		$ 1,196,559	$ 1,192,329	$ 741,931
Common Stock
Investment Company, Net Assets [Roll Forward]
Beginning balance (in shares)		107,916,166		65,316,085	107,916,166	65,316,085	65,316,085
Beginning balance		$ 108		$ 65	$ 108	$ 65	$ 65
Issuance of common stock in connection with acquisition of sierra (in shares)						45,986,926
Issuance of common stock in connection with acquisition of Sierra						$ 46
Purchases of shares in repurchase plan (in shares)					(1,849,096)	(3,386,845)
Purchase of shares in repurchase plan					$ (2)	$ (3)
Ending balance (in shares)	106,067,070		107,916,166		106,067,070	107,916,166	65,316,085
Ending balance	$ 106		$ 108		$ 106	$ 108	$ 65
Additional paid-in capital
Investment Company, Net Assets [Roll Forward]
Beginning balance		1,855,975		1,027,687	1,855,975	1,027,687	1,027,707
Return of capital, merger and other tax related adjustments					13,252	288,888	1,629
Deemed contribution - from Adviser (See Note 10)						72,130
Issuance of common stock in connection with acquisition of Sierra						499,372
Purchase of shares in repurchase plan					(14,770)	(32,102)
Return of capital distributions							(1,649)
Ending balance	1,854,457		1,855,975		1,854,457	1,855,975	1,027,687
Total Distributable Earnings (Loss)
Investment Company, Net Assets [Roll Forward]
Beginning balance		$ (663,754)		$ (285,821)	(663,754)	(285,821)	(309,967)
Net investment income					127,804	115,656	58,960
Net realized(loss) gain on investments / foreign currency transactions / forward currency contracts					(62,750)	12,861	(3,379)
Net unrealized (depreciation) appreciation of investments / CSA / foreign currency transactions					62,624	(123,041)	22,105
Provision for taxes					321	(795)	(1)
Return of capital, merger and other tax related adjustments					(13,252)	(288,888)	(1,629)
Distributions of net investment income					(108,997)	(93,726)	(51,910)
Ending balance	$ (658,004)		$ (663,754)		$ (658,004)	$ (663,754)	$ (285,821)