Restructuring and Repositioning Expenses - Restructuring Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Severance and other employee costs	$ 3.6	$ 10.0	$ 4.1	$ 9.3
Asset impairments	0.1	4.1	4.1	4.5
Facility exit costs	0.0	0.2	0.0	0.2
Other associated costs	0.2	0.0	0.9	0.0
Total restructuring expenses and asset impairments	3.9	14.3	9.1	14.0
Less: restructuring expenses and asset impairments reflected in discontinued operations	0.1	0.0	0.3	0.8
Total restructuring expenses and asset impairments from continuing operations	$ 3.8	$ 14.3	$ 8.8	$ 13.2