Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies (Details)	3 Months Ended
Mar. 31, 2012 segment entity
Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies
Number of operating segments	3
Number of United States subsidiaries and affiliates filed voluntary petitions for reorganization	61

Number of entities included in the bankruptcy proceeding.

No definition available.

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Namespace Prefix:	gra_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant