Revenue Recognition - Schedule of Changes in Warranty Liability and Unearned Extended Warranty Premiums (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Abstract]
Balance at beginning of period	$ 64.4	$ 68.2
Deferred revenue for new service warranties	5.0	5.9
Amortization of deferred revenue	(6.8)	(7.2)
Foreign currency translation	0.4	0.3
Balance at end of period	$ 63.0	$ 67.2