Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 19.5	$ 16.3
Other comprehensive income:
Foreign currency translation adjustment	13.9	0.7
Other comprehensive income	13.9	0.7
Comprehensive income	$ 33.4	$ 17.0