Restructuring and Repositioning Expenses - Restructuring Costs by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	$ 4.4	$ (0.6)	$ 5.0	$ (1.1)
Restructuring expenses and asset impairments reflected in discontinued operations	0.1	(0.3)	0.2	0.8
Total restructuring expenses and asset impairments	4.5	(0.9)	5.2	(0.3)
Operating Segments | SCC
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	1.3	(0.6)	1.9	(1.0)
Operating Segments | SBM
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	3.2	0.1	3.2	(0.4)
Corporate
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses and asset impairments from continuing operations	$ (0.1)	$ (0.1)	$ (0.1)	$ 0.3