Pension Plans and Other Postretirement Benefits - Pension and Postretirement Plan Contributions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Other postretirement benefits payments	$ 0.7	$ 0.7	$ 1.9	$ 2.3
Chemetall Surface Treatment
Defined Benefit Plan Disclosure [Line Items]
Pension contributions		1.0		2.9
Continuing Operations
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	$ 2.6	$ 2.4	$ 7.7	$ 8.5