Accumulated Other Comprehensive (Loss) Income (Components of accumulated comprehensive loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 331.6	$ 329.3	$ 349.6	$ 312.6
Other comprehensive income (loss)	3.3	(2.1)	(12.8)	3.9
Ending balance	316.2	330.2	316.2	330.2
Cumulative Translation Adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(39.0)	(20.6)	(22.4)	(21.3)
Other comprehensive income (loss)	2.9	(2.5)	(13.7)	(1.8)
Ending balance	(36.1)	(23.1)	(36.1)	(23.1)
Pension and Postretirement Benefits
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(14.1)	(14.3)	(14.6)	(19.6)
Other comprehensive income (loss)	(0.4)	(0.4)	(0.9)	(5.7)
Ending balance	(13.7)	(13.9)	(13.7)	(13.9)
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(53.1)	(34.9)	(37.0)	(40.9)
Ending balance	$ (49.8)	$ (37.0)	$ (49.8)	$ (37.0)