Goodwill and Other Intangible Assets - Summary of Changes in the Company's Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Balance on beginning	$ 254,110	$ 253,398
Fiscal year business combinations	7,993	3,072
Goodwill included within assets held for sale		(2,215)
Other		(145)
Balance on ending	$ 262,103	$ 254,110