Forward Currency Contracts - Schedule of Forward Currency Contract, Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Open Forward Foreign Currency Contract [Line Items]
Unrealized appreciation on forward currency contracts	$ 10,466	$ 32,333
Net amounts presented in the Consolidated Statement of Financial Condition	10,007	32,333
Foreign exchange
Open Forward Foreign Currency Contract [Line Items]
Unrealized appreciation on forward currency contracts	10,466	32,333
Unrealized depreciation on forward currency contracts	(459)	0
Net amounts presented in the Consolidated Statement of Financial Condition	10,007	32,333
Collateral (received) pledged	0	0
Net amount	$ 10,007	$ 32,333