Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Consolidated Statement of Other Comprehensive Income (Loss) [Abstract]
Net income	$ 16.3	$ 24.0	$ 57.9	$ 39.8
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustment	0.3	(4.9)	0.6	(8.7)
Other comprehensive (loss) income	0.3	(4.9)	0.6	(8.7)
Comprehensive income	$ 16.6	$ 19.1	$ 58.5	$ 31.1