Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Unrecognized income tax benefits at beginning of year	$ 700	$ 568	$ 509
Additions for tax positions of prior years	0	34
Additions for tax positions of current year	138	138	104
Tax examination and other settlements	(64)	(40)	(45)
Unrecognized income tax benefits at end of year	$ 774	$ 700	$ 568