Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Condensed Consolidated Statement of Other Comprehensive Income (Loss) [Abstract]
Net income	$ (6.9)	$ 6.3
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(2.2)	(0.9)
Reclassification of adjustments included in net income [Abstract]
Other comprehensive income (loss)	(2.2)	(0.9)
Comprehensive income	$ (9.1)	$ 5.4