Income Taxes - Summary of Income Tax Benefit and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 33.4	$ 24.4	$ 58.3	$ (29.6)
Income tax expense (benefit)	$ 9.9	$ 7.6	$ 17.5	$ (5.5)
Effective income tax rate	29.60%	31.10%	30.00%	18.60%