Income Taxes - Summary of Income Tax Benefit and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 15.3	$ 34.7	$ (1.6)	$ 27.6
Income tax (benefit) expense	$ 4.5	$ 9.5	$ (0.3)	$ 8.1
Effective income tax rate	29.40%	27.40%	18.70%	29.30%