Income Taxes - Summary of Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Current:
Federal	$ 93	$ (424)	$ 16,184
State	457	601	3,434
Foreign	0	0	0
Current total	550	177	19,618
Deferred:
Federal	(30,411)	(152)	(19,171)
State	(5,440)	(182)	(3,859)
Foreign	0	0	0
Deferred total	(35,851)	(334)	(23,030)
Income tax (benefit) expense	$ (35,301)	$ (157)	$ (3,412)