Gladstone Capital Corporation Annual report pursuant to Section 13 and 15(d)

FEDERAL AND STATE INCOME TAXES (Details) - USD ($)	12 Months Ended
FEDERAL AND STATE INCOME TAXES (Details) - USD ($)	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Schedule of Investments [Abstract]
Investment company, target percentage of taxable income to distribute to shareholders (up to)	100.00%
Income tax provisions	$ 0	$ 0	$ 0
Investment company, percentage of ordinary income distribution	98.00%
Investment company, percentage of net capital gains distribution	98.20%
Excise tax	$ 0	$ 0	$ 0

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.