Restructuring and Restructuring Related Charges (Accrued Liability) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Reserve [Roll Forward]
Balance at beginning of period	$ 0.8	$ 0.5
Add: Charges	(7.8)	(0.8)	$ (0.8)
Less: Payments	1.4	0.5
Balance at end of period	7.2	0.8	0.5
Termination benefits
Restructuring Reserve [Roll Forward]
Balance at beginning of period	0.3	0.0
Add: Charges	(7.3)	(0.5)
Less: Payments	1.0	0.2
Balance at end of period	6.6	0.3	0.0
Other restructuring costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period	0.5	0.5
Add: Charges	(0.5)	(0.3)
Less: Payments	0.4	0.3
Balance at end of period	$ 0.6	$ 0.5	$ 0.5