Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 55.3	$ 39.3	$ 74.8	$ 55.6
Other comprehensive (loss) income:
Foreign currency translation adjustment	(1.6)	(3.4)	12.3	(2.7)
Other comprehensive (loss) income	(1.6)	(3.4)	12.3	(2.7)
Comprehensive income	$ 53.7	$ 35.9	$ 87.1	$ 52.9