Income Taxes - Summary of Income Tax Benefit and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Income Tax Disclosure [Abstract]
(Loss) income before income taxes	$ (29.7)	$ 0.6	$ (54.1)	$ (16.8)
Income tax (benefit)	$ (7.7)	$ (0.1)	$ (13.2)	$ (4.7)
Effective income tax rate	25.90%	16.70%	24.40%	28.00%