Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,005.6	$ 860.2	$ 904.0	$ 767.5
Other comprehensive income/(loss), net of tax	(12.2)	4.0	(30.5)	16.3
Ending balance	1,047.3	901.4	1,047.3	901.4
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(22.7)
Other comprehensive income/(loss), net of tax			(5.5)
Ending balance	(28.2)		(28.2)
Pension Benefits Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(2.4)
Other comprehensive income/(loss), net of tax			0.0
Ending balance	(2.4)		(2.4)
Cash Flow Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			0.0
Other comprehensive income/(loss), net of tax			(25.0)
Ending balance	(25.0)		(25.0)
Accumulated Other Comprehensive Loss, net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(43.4)	(27.8)	(25.1)	(40.1)
Other comprehensive income/(loss), net of tax	(12.2)	4.0	(30.5)	16.3
Ending balance	$ (55.6)	$ (23.8)	$ (55.6)	$ (23.8)