Restructuring Expenses and Repositioning Expenses - Expenses and Asset Impairments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 1.8	$ 2.5	$ 18.2	$ 8.8
Grace Catalysts Technologies [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	1.6	0.5	2.7	3.8
Grace Materials Technologies [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	(0.1)	0.2	15.1	0.8
Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 0.3	$ 1.8	$ 0.4	$ 4.2