Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 13.7	$ 13.5	$ 22.7	$ 35.5
Other comprehensive income, net of tax:
Defined benefit plan adjustments	0.1	0.3	0.2	0.5
Foreign currency translation gains (loss), net	2.8	(0.2)	1.2	1.6
Other comprehensive income, net of tax	2.9	0.1	1.4	2.1
Comprehensive income	$ 16.6	$ 13.6	$ 24.1	$ 37.6