Leases - Summary of Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 27.9	$ 23.6
Operating cash flows from finance leases	1.0	0.7
Financing cash flows from finance leases	27.0	20.5	$ 9.9
Non-cash items:
Right-of-use Assets Obtained In Exchange For New Operating Liabilities	39.6	33.8
Right-of-use Assets Obtained In Exchange For New Finance Liabilities	$ 33.3	$ 22.0