Restructuring and Repositioning Expenses - Restructuring Costs by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	$ 3.8	$ 14.3	$ 8.8	$ 13.2
Restructuring expenses and asset impairments reflected in discontinued operations	0.1	0.0	0.3	0.8
Total restructuring expenses and asset impairments	3.9	14.3	9.1	14.0
Operating Segments | SCC
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	1.5	11.9	3.4	10.9
Operating Segments | SBM
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	0.7	2.3	3.9	1.9
Corporate
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	$ 1.6	$ 0.1	$ 1.5	$ 0.4