Unconsolidated Affiliate (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Investment in unconsolidated affiliates
Equity method investment, ownership interest (as a percent)	50.00%		50.00%
Investment in unconsolidated affiliate	$ 99,500,000		$ 99,500,000		$ 85,500,000
Equity in earnings of unconsolidated affiliate	9,200,000	3,200,000	14,300,000	8,900,000
Grace sales of catalysts to ART	52,100,000	49,200,000	105,000,000	99,700,000
Charges for fixed costs, research and development and selling, general and administrative services to ART	7,100,000	7,700,000	15,500,000	15,100,000
Commitment fee on credit facility (as a percent)			0.10%
W.R. Grace & Co
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	15,000,000.0		15,000,000.0
Chevron
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	$ 15,000,000.0		$ 15,000,000.0