Income Taxes - Schedule of Income Tax Expense and Effective Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income tax expense	$ 12.6	$ 14.0	$ 45.9	$ 25.9
Effective tax rate percentage	24.80%	24.40%	25.80%	25.10%