Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense for intangible assets	$ 20.0	$ 18.0	$ 18.6