Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Current:
Federal	$ 16,077	$ 17,083	$ 7,921
State	6,237	7,086	4,722
Deferred
Federal	8,263	(2,643)	(3,168)
State	3,098	(901)	(1,958)
Income tax expense	$ 33,675	$ 20,625	$ 7,517