Forward Currency Contracts - Schedule of Realized and Unrealized Gain (Loss) on Forward Currency Contract (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Open Forward Foreign Currency Contract [Line Items]
Realized gain (loss) on forward currency contracts recognized in income	$ 2,021	$ 1,080	$ 3,192	$ 1,080
Change in unrealized appreciation (depreciation) on forward currency contracts recognized in income	(5,431)	11,922	(22,326)	14,059
Foreign exchange
Open Forward Foreign Currency Contract [Line Items]
Realized gain (loss) on forward currency contracts recognized in income	2,021	1,080	3,192	1,080
Change in unrealized appreciation (depreciation) on forward currency contracts recognized in income	$ (5,431)	$ 11,922	$ (22,326)	$ 14,059