Related Party Transactions (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity method investment ownership interest (percent)	50.00%
Investment in unconsolidated affiliate	$ 182,600,000		$ 181,900,000
Equity in earnings of unconsolidated affiliate	1,200,000	$ 4,100,000
ART's assets, liabilities and results of operations
Current assets	281,800,000		300,700,000
Noncurrent assets	249,500,000		237,800,000
Total assets	531,300,000		538,500,000
Current liabilities	168,500,000		177,100,000
Noncurrent liabilities	300,000		300,000
Total liabilities	168,800,000		177,400,000
Net sales	75,300,000	111,500,000
Costs and expenses applicable to net sales	68,000,000.0	97,300,000
Income before income taxes	2,900,000	9,700,000
Net income	2,500,000	9,200,000
Related Party Transactions [Abstract]
Product manufactured for ART	71,100,000	66,800,000
Mark-up on product manufactured for ART included as a reduction of Grace’s cost of goods sold	1,400,000	1,300,000
Charges for fixed costs; research and development; selling, general and administrative services; and depreciation to ART	14,100,000	12,800,000
Investment in unconsolidated affiliates
Operating Income Included in Income (Loss) from Equity Method Investments	1,600,000	3,900,000
Depreciation and Amortization Included in Income (Loss) From Equity Method Investments	(400,000)	(100,000)
Interest Expense and Income Taxes Included in Income (Loss) From Equity Method Investments	$ 0	300,000
Debt Instrument, Frequency of Periodic Payment	monthly
Loan Repayment Period, Max	P8Y
Current asset, related party	$ 184,700,000		173,900,000
Current liability, related party	184,700,000		173,900,000
Affiliated Entity [Member]
Investment in unconsolidated affiliates
Accounts receivable	1,800,000		3,600,000
Revenue from Related Parties	$ 1,900,000	$ 3,200,000
ART [Member]
Investment in unconsolidated affiliates
Basis spread on variable rate	1.25%
Accounts receivable	$ 19,500,000		17,500,000
Current asset, related party	184,700,000		173,900,000
Accounts payable	27,500,000		37,700,000
Debt payable within one year	9,800,000		9,900,000
Debt payable after one year	37,200,000		37,500,000
Current liability, related party	184,700,000		173,900,000
Grace LOC to ART [Member]
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	$ 15,000,000.0
Commitment fee on credit facility (as a percent)	0.10%
Chevron
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	$ 15,000,000.0
Commitment fee on credit facility (as a percent)	0.10%
Credit facility amount outstanding	$ 0		$ 0
Joint Venture [Member]
Investment in unconsolidated affiliates
Noncontrolling Interest, Ownership Percentage by Parent	87.50%