Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Current
Federal			$ (39)
State	$ 560	$ 231	202
Total current income tax provision	560	231	163
Deferred
Federal	(7,392)	(47,879)	4,494
State	(1,913)	(4,342)	1,171
Total deferred income tax provision	(9,305)	(52,221)	5,665
(Benefit) provision for income taxes	$ (8,745)	$ (51,990)	$ 5,828