Equity Method Investments - Summarized financial information for the equity method investments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Assets
Investments at fair value (cost of $667,419 and $715,385, respectively)	$ 845,913		$ 845,913		$ 845,913	$ 675,211
Cash and cash equivalents					7,783	26,622	$ 13,188
Other assets					28	111
Total assets					898,811	749,189
Liabilities
Other liabilities					134	108
Total liabilities					551,617	460,005
Total liabilities and members' capital					$ 898,811	749,189
Equity Method Investments [Member]
Assets
Investments at fair value (cost of $667,419 and $715,385, respectively)	645,894		645,894			688,366
Cash and cash equivalents	1,498		1,498			1,057
Other assets	11,310		11,310			10,306
Total assets	658,702		658,702			699,729
Liabilities
Accrued expenses	1,234		1,234			978
Other liabilities	1,204		1,204			1,297
Total liabilities	2,438		2,438			2,275
Total equity	656,264		656,264			697,454
Total liabilities and members' capital	658,702		658,702			$ 699,729
Total income	13,008	$ 19,253	42,117	$ 55,187
Total expenses	1,459	1,845	4,256	5,585
Net investment income	11,549	17,408	37,861	49,602
Other income/(expenses)
Net realized gain	(137)	100	(1,088)	706
Net change in unrealized depreciation	(840)	(1,247)	(9,152)	(3,156)
Net income	$ 10,572	$ 16,261	$ 27,621	$ 47,152