Restructuring Expenses and Asset Impairments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Restructuring Expenses and Asset Impairments (In millions)
Accruals for severance and other costs	$ 4,800,000	$ 800,000	$ 18,700,000	$ 3,500,000
Asset impairments	0	4,600,000	0	14,300,000
Other than Temporary Impairment Losses, Investments				4,500,000
Total restructuring expenses and asset impairments	4,800,000	5,400,000	18,700,000	17,800,000
Restructuring Liability (In millions)
Balance, December 31, 2014			4,500,000
Accruals for severance and other costs	4,800,000	$ 800,000	18,700,000	3,500,000
Payments			(12,100,000)	(4,800,000)
Currency translation adjustments and other			300,000
Balance, September 30, 2015	11,400,000		$ 11,400,000
Grace Catalysts Technologies [Member]
Restructuring Expenses and Asset Impairments (In millions)
Accruals for severance and other costs	0.5
Restructuring Liability (In millions)
Accruals for severance and other costs	0.5
Grace Construction Products
Restructuring Expenses and Asset Impairments (In millions)
Accruals for severance and other costs	0.4
Asset impairments				$ 9,800,000
Restructuring Liability (In millions)
Accruals for severance and other costs	0.4
Grace Materials Technologies [Member]
Restructuring Expenses and Asset Impairments (In millions)
Accruals for severance and other costs	0.3
Restructuring Liability (In millions)
Accruals for severance and other costs	0.3
Corporate Segment [Member]
Restructuring Expenses and Asset Impairments (In millions)
Accruals for severance and other costs	3.6
Restructuring Liability (In millions)
Accruals for severance and other costs	$ 3.6