Restructuring and Repositioning Expenses, Asset Impairments - Restructuring Expenses and Asset Impairments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring and Related Activities [Abstract]
Severance and other employee costs	$ 0.0	$ 0.2	$ 1.9	$ 0.5
Asset impairments	0.2	3.8	1.2	4.0
Other associated costs	0.2	0.5	0.4	0.7
Total restructuring expenses and asset impairments	0.4	4.5	3.5	5.2
Less: restructuring expenses and asset impairments reflected in discontinued operations	0.0	0.1	0.0	0.2
Total restructuring expenses and asset impairments from continuing operations	$ 0.4	$ 4.4	$ 3.5	$ 5.0