Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income tax expense	$ 13.0	$ 5.2	$ 41.4	$ 21.5
Effective income tax rate, percent	24.70%	24.60%	24.40%	24.50%
Deferred Income Tax Liabilities, Net of Deferred Income Tax Assets	$ 24.5		$ 24.5		$ 23.2
Valuation allowance, deferred tax asset, amount	1.1		1.1		1.2
Deferred tax liability, net	$ 25.6		$ 25.6		$ 24.4