Name:	gra_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsReceivableCurrent
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Data Type:	xbrli:monetaryItemType
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Contractually required future rental payments, which are receivable on non-cancelable subleasing arrangements within the fifth year of the balance sheet date.

No definition available.

Name:	gra_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsReceivableInFiveYears
Namespace Prefix:	gra_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Contractually required future rental payments, which are receivable on non-cancelable subleasing arrangements within the fourth year of the balance sheet date.

No definition available.

Name:	gra_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsReceivableInFourYears
Namespace Prefix:	gra_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Contractually required future rental payments, which are receivable on non-cancelable subleasing arrangements after the fifth year of the balance sheet date.

No definition available.

Name:	gra_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsReceivableInThereafter
Namespace Prefix:	gra_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Contractually required future rental payments, which are receivable on non-cancelable subleasing arrangements within the third year of the balance sheet date.

No definition available.

Name:	gra_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsReceivableInThreeYears
Namespace Prefix:	gra_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Contractually required future rental payments, which are receivable on non-cancelable subleasing arrangements within the second year of the balance sheet date.

No definition available.

Name:	gra_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsReceivableInTwoYears
Namespace Prefix:	gra_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 122

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph b(i)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Data Type:	xbrli:monetaryItemType
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Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Data Type:	xbrli:monetaryItemType
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Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Amount of required minimum rental payments maturing after the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.