Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 13.9	$ 9.0	$ 26.9	$ 16.1
Effective Income Tax Rate Reconciliation, Percent	23.60%	25.10%	24.40%	25.20%
Deferred Tax Liabilities, Gross	$ 50.0		$ 50.0		$ 49.8
Deferred Tax Assets, Valuation Allowance	0.8		0.8		0.9
Deferred tax liability, net	$ 50.8		$ 50.8		$ 50.7