CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Operating Activities
Net increase (decrease) in net assets resulting from operations	$ 110,400	$ 37,239	$ 317,462	$ (61,021)
Net realized (gain) loss on investments	(1,018)	4,092	3,611	17,549
Net change in unrealized (gains) losses on investments	(8,921)	19,885	(102,585)	159,982
Net unrealized (appreciation) depreciation on foreign currency forward contracts	(1,105)	(482)	(823)	(582)
Net unrealized (appreciation) depreciation on translation of assets and liabilities in foreign currencies	(14,240)	(14,488)	(4,590)	(19,095)
Payment-in-kind interest capitalized			(5,909)	(3,627)
Net accretion of discount and amortization of premium			(10,914)	(3,221)
Amortization of deferred financing costs			4,098	2,693
Amortization of offering costs			38	1,462
Purchases of investments			(2,306,194)	(5,826,781)
Proceeds from sale of investments and principal repayments			1,441,363	1,674,871
Changes in operating assets and liabilities:
Interest receivable			(4,070)	(29,827)
Receivable for investments sold			(51,699)	(168,247)
Other assets			6,600	(5,675)
Payable for investments purchased			11,991	211,650
Management and performance-based incentive fees payable			4,450	7,561
Accrued administrative services expense payable			(1,467)	1,829
Interest payable			6,417	7,622
Other liabilities and accrued expenses			(3,032)	11,631
Net Cash Used in/Provided by Operating Activities			(695,253)	(4,021,226)
Financing Activities
Issuances of debt			2,176,014	3,770,462
Payments of debt			(1,970,099)	(1,683,910)
Financing costs paid and deferred			(5,071)	(22,823)
Proceeds from issuance of common shares			1,135,145	2,073,250
Repurchased shares, net of early repurchase deduction paid			(259,919)	(1,821)
Distributions paid			(91,666)	(34,019)
Offering costs paid and deferred			(38)	(2,006)
Net Cash Used in/Provided by Financing Activities			984,366	4,099,133
Cash Cash Equivalents And Foreign Currencies [Abstract]
Net increase (decrease) in cash and cash equivalents and foreign currencies during the period			289,113	77,907
Effect of foreign exchange rate changes on cash and cash equivalents			(25)	40
Cash, cash equivalents and foreign currencies at beginning of period			51,658	50	$ 50
Cash, Cash Equivalents and Foreign Currencies at the End of Period	340,746	77,997	340,746	77,997	$ 51,658
Supplemental Disclosure and Non-Cash Information
Cash interest paid			105,826	27,327
Distributions payable			23,702	11,889
Reinvestment of distributions during the period			73,642	33,342
PIK income	$ 2,983	$ 1,679	$ 6,728	$ 3,627