Restructuring Expenses and Repositioning Expenses - Expenses and Asset Impairments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 2.8	$ 8.5
Grace Catalysts Technologies [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0.4	0.5
Grace Materials Technologies [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0.3	7.9
Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 2.1	$ 0.1