Accumulated Other Comprehensive Loss (Components of accumulated comprehensive loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			$ 231.7
Other comprehensive loss adjustments	$ 7.7	$ (1.0)	19.5	$ (4.6)
Ending balance	275.9		275.9
Cumulative Translation Adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(30.8)	(16.9)
Other comprehensive loss adjustments			18.9	(5.3)
Ending balance	(11.9)	(22.2)	(11.9)	(22.2)
Pension and Postretirement Benefits
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(11.9)	(13.1)
Other comprehensive loss adjustments			0.6	0.7
Ending balance	(11.3)	(12.4)	(11.3)	(12.4)
Total
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(42.7)	(30.0)
Ending balance	$ (23.2)	$ (34.6)	$ (23.2)	$ (34.6)