Operating Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 segment	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting [Abstract]
Number of operating segments	3
Net Sales
Net sales	$ 838.0	$ 802.8	$ 1,582.5	$ 1,512.7
Adjusted EBIT
Gain on termination of postretirement plans related to current businesses	4.7	0	4.7	0
Grace Adjusted EBIT	166.1	153.3	277.4	270.1
Reconciliation of operating segment data to financial statements
Grace Adjusted EBIT	166.1	153.3	277.4	270.1
Costs related to Chapter 11	(3.0)	(3.3)	(9.3)	(7.1)
Asbestos-related costs	(4.3)	(2.1)	(5.8)	(4.2)
Asbestos and bankruptcy related charges, net	2.4	0	(6.4)	0
Pension MTM adjustment and other related costs, net	0	0	4.8	(2.5)
gain on termination of postretirement plans related to divested businesses	3.2	0	3.2	0
Restructuring expenses and related asset impairments	(11.7)	(4.3)	(12.4)	(5.1)
Gain on sale of product line	0.2	0	0.2	0
Divestment Expenses	(0.2)		(0.2)	0
Interest expense and related financing costs	(11.1)	(10.9)	(22.3)	(21.4)
Interest accretion on deferred payment obligations	(13.6)	0	(21.8)	0
Consolidated Exchange Rate Net Charges		0		(6.9)
Investment Income, Interest	0.5	0.1	1.0	0.3
Currency transaction loss in Venezuela	0	0		8.5
Net Income (Loss) Attributable to Noncontrolling Interest, Reconciliation of Operating Segment Data	0.5	0.5	0.7	0.8
Income before income taxes	129.0	133.3	209.1	224.0
Segment Reconciling Items [Member]
Reconciliation of operating segment data to financial statements
Consolidated Exchange Rate Net Charges			0
Currency transaction loss in Venezuela				6.9
Grace Catalysts Technologies [Member]
Net Sales
Net sales	313.2	290.9	597.7	557.4
Adjusted EBIT
Segment operating income	97.5	93.8	168.7	171.0
Grace Materials Technologies [Member]
Net Sales
Net sales	236.1	228.7	455.9	443.6
Adjusted EBIT
Segment operating income	49.7	44.8	95.2	89.1
Construction Products
Net Sales
Net sales	288.7	283.2	528.9	511.7
Adjusted EBIT
Segment operating income	45.0	45.3	70.4	68.1
Corporate, Non-Segment [Member]
Adjusted EBIT
Segment operating income	(22.8)	(23.7)	(45.3)	(44.5)
Certain Pension Costs	$ 8.0	$ 6.9	$ 16.3	$ 13.6