Accumulated Other Comprehensive Income (Loss) (Components of accumulated comprehensive loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 288.0	$ 236.0	$ 212.2
Currency translation	(23.0)	24.8	(12.7)
Ending balance	312.6	288.0	236.0
Cumulative Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(11.6)	(30.8)	(16.9)
Currency translation	(9.7)	19.2	(13.9)
Pension and OPEB activity, net of tax	0.0	0.0	0.0
Ending balance	(21.3)	(11.6)	(30.8)
Pension and Postretirement Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(6.3)	(11.9)	(13.1)
Currency translation	0.0	0.0	0.0
Pension and OPEB activity, net of tax	(13.3)	5.6	1.2
Ending balance	(19.6)	(6.3)	(11.9)
Accumulated Other Comprehensive (Loss) Income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(17.9)	(42.7)	(30.0)
Currency translation	(9.7)	19.2	(13.9)
Pension and OPEB activity, net of tax	(13.3)	5.6	1.2
Ending balance	$ (40.9)	$ (17.9)	$ (42.7)