Revenue Recognition - Schedule of Changes in Warranty Liability and Unearned Extended Warranty Premiums (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Abstract]
Balance at beginning of period	$ 68.2	$ 30.7
Adoption of ASC 606		35.7
Deferred revenue for new service warranties	5.9	10.5
Amortization of deferred revenue	(7.2)	(10.8)
Foreign currency translation	0.3
Balance at end of period	$ 67.2	$ 66.1