Property and Equipment - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation	$ 23.7	$ 27.6	$ 29.0
Impairment charge	15.6
Leasehold Improvements And Furniture And Fixtures
Property, Plant and Equipment [Line Items]
Impairment charge	$ 2.8