Income Taxes - Summary of Income Tax (Benefit) and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
(Loss) before income taxes	$ (14.6)	$ (22.1)
Income tax (benefit)	$ (4.2)	$ (5.7)
Effective income tax rate	28.80%	25.80%