BORROWINGS - Fair Value Narrative (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2026	Sep. 30, 2025
Debt Instrument [Line Items]
Investments, at fair value	$ 906,844	$ 859,124	[1]
Collateral Pledged
Debt Instrument [Line Items]
Investments, at fair value	$ 818,800	$ 754,600
Credit Facility | Line of Credit | Revolving Line of Credit
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.60%	2.60%
Unused fee percentage	0.60%	1.00%

[1] Cumulative gross unrealized depreciation for federal income tax purposes is $59.7 million; cumulative gross unrealized appreciation for federal income tax purposes is $34.1 million. Cumulative net unrealized depreciation is $25.5 million, based on a tax cost of $884.7 million.