Restructuring Expenses and Related Asset Impairments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Restructuring expenses and related asset impairments
Severance and other employee related costs	$ 2.9	$ 0.2
Asset impairments and other restructuring costs	0.1
Total restructuring expenses and related asset impairments	3.0	0.2
Restructuring Liability
Balance at beginning of the period	5.9
Accruals for severance and other employee related costs	2.9
Payments	(2.2)
Total restructuring liability	6.6
Grace Construction Products
Restructuring expenses and related asset impairments
Total restructuring expenses and related asset impairments	0.7
Grace Materials Products
Restructuring expenses and related asset impairments
Total restructuring expenses and related asset impairments	0.3
Grace Catalyst Products
Restructuring expenses and related asset impairments
Total restructuring expenses and related asset impairments	0.5
Corporate
Restructuring expenses and related asset impairments
Total restructuring expenses and related asset impairments	$ 1.5