Acquisitions (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	$ 30.2	$ 30.2
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	3.3	$ 3.3
Weighted Average Amortization Period (in years)		20 years
Inventories	3.8
Properties and equipment	98.5	$ 98.5
Goodwill	395.2	395.2	$ 336.5
Intangible assets	59.1	59.1
Net assets acquired	248.7	248.7
Goodwill, Acquired During Period		60.9
Goodwill, Foreign Currency Translation Gain (Loss)		0.3
Goodwill, Written off Related to Sale of Business Unit		(2.5)
Business Acquisition, Goodwill, Expected Tax Deductible Amount	43.0	$ 43.0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles	(6.4)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment	(1.2)
Goodwill, Purchase Accounting Adjustments	(9.0)
Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Weighted Average Amortization Period (in years)		20 years
Intangible assets	8.3	$ 8.3
Trademarks [Member]
Business Acquisition [Line Items]
Weighted Average Amortization Period (in years)		20 years
Intangible assets	13.4	$ 13.4
Customer Lists [Member]
Business Acquisition [Line Items]
Weighted Average Amortization Period (in years)		20 years
Intangible assets	37.4	$ 37.4
Polyolefin Catalysts [Member]
Business Acquisition [Line Items]
Goodwill	60.9	60.9
Grace Catalysts Technologies [Member]
Business Acquisition [Line Items]
Goodwill	353.8	353.8	292.8
Goodwill, Acquired During Period		60.9
Goodwill, Foreign Currency Translation Gain (Loss)		0.1
Goodwill, Written off Related to Sale of Business Unit		0.0
Grace Materials Technologies [Member]
Business Acquisition [Line Items]
Goodwill	$ 41.4	41.4	$ 43.7
Goodwill, Acquired During Period		0.0
Goodwill, Foreign Currency Translation Gain (Loss)		0.2
Goodwill, Written off Related to Sale of Business Unit		$ (2.5)