Income Taxes - Summary of Income Tax Benefit and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 24.4	$ 15.3	$ (29.6)	$ (1.6)
Income tax expense (benefit)	$ 7.6	$ 4.5	$ (5.5)	$ (0.3)
Effective income tax rate	31.10%	29.40%	18.60%	18.70%