Supplemental Disclosure of Cash Flow Information - Schedule of Supplemental Disclosure of Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Cash paid during the period for:
Income taxes, net	$ 21,936	$ 25,292	$ 5,133
Interest	$ 8,928	$ 11,722	$ 12,601