Unconsolidated Affiliate (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 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	$ 90,800,000		$ 90,800,000		$ 85,500,000
Equity in earnings of unconsolidated affiliate	2,800,000	4,900,000	17,100,000	13,800,000
Grace sales of catalysts to ART	69,200,000	53,400,000	174,200,000	153,100,000
Charges for fixed costs, research and development and selling, general and administrative services to ART	7,000,000	7,200,000	22,500,000	22,300,000
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