Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,482.8	$ 1,176.6	$ 1,379.1	$ 1,070.1
Other comprehensive income, net of tax	(5.4)	17.5	22.2	40.4
Ending balance	1,542.6	1,247.3	1,542.6	1,247.3
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(31.2)
Other comprehensive income, net of tax			2.3
Ending balance	(28.9)		(28.9)
Pension Benefits Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(2.2)
Other comprehensive income, net of tax			0.0
Ending balance	(2.2)		(2.2)
Cash Flow Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(18.4)
Other comprehensive income, net of tax			19.9
Ending balance	1.5		1.5
Accumulated Other Comprehensive Loss, net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(24.2)	(67.7)	(51.8)	(90.6)
Other comprehensive income, net of tax	(5.4)	17.5	22.2	40.4
Ending balance	$ (29.6)	$ (50.2)	$ (29.6)	$ (50.2)