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Income Taxes - Schedule of Reconciliation between Effective Tax Rate Income from Continuing Operations and Statutory Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Income tax expense at federal statutory rate	$ 13,290	$ 3,878	$ 18,796
Increase (reduction) in income taxes resulting from:
State taxes, net of federal tax benefit	1,785	660	1,397
Nondeductible stock compensation expenses	(21)
Permanent items	261	63	92
Change in valuation allowances	(50)	(646)	531
US Tax Cuts and Jobs Act Impact		(22,015)
162(m) Limitation	119
Impact of changing rates on deferred tax assets	484	(773)	(353)
Expired tax attributes	111	1,088	409
Other	(273)	319	2
Provision (Benefit) for income taxes	$ 15,706	$ (17,426)	$ 20,874

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