Represents the amortization period of debt instrument.

No definition available.

Name:	grif_DebtInstrumentAmortizationPeriod
Namespace Prefix:	grif_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of multi-story office buildings used as collateral for the loan.

+ References

No definition available.

+ Details

Name:	grif_NumberOfOfficeBuildingsUsedAsCollateral
Namespace Prefix:	grif_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of wholly-owned subsidiaries.

+ References

No definition available.

+ Details

Name:	grif_NumberOfWhollyOwnedSubsidiaries
Namespace Prefix:	grif_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13,16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate stated in the contractual debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer plus capital lease obligations due to be paid more than one year after the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section H

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Obligation related to long-term debt (excluding convertible debt) and capital leases, the portion which is due in one year or less in the future.

+ References

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified																							1 Months Ended	9 Months Ended
	Sep. 01, 2012	Dec. 03, 2011	Sep. 01, 2012 Nonrecourse mortgages	Dec. 03, 2011 Nonrecourse mortgages	Sep. 01, 2012 Nonrecourse variable rate mortgage, due October 2, 2017	Dec. 03, 2011 Nonrecourse variable rate mortgage, due October 2, 2017	Sep. 01, 2012 Nonrecourse mortgages: 6.30%, due May 1, 2014	Dec. 03, 2011 Nonrecourse mortgages: 6.30%, due May 1, 2014	Sep. 01, 2012 Nonrecourse mortgages: 5.73%, due August 1, 2015	Dec. 03, 2011 Nonrecourse mortgages: 5.73%, due August 1, 2015	Sep. 01, 2012 Nonrecourse mortgages: 8.13%, due April 1, 2016	Dec. 03, 2011 Nonrecourse mortgages: 8.13%, due April 1, 2016	Sep. 01, 2012 Nonrecourse mortgages: 7.0%, due October 1, 2017	Dec. 03, 2011 Nonrecourse mortgages: 7.0%, due October 1, 2017	Sep. 01, 2012 Nonrecourse variable rate mortgage, due February 1, 2019	Dec. 03, 2011 Nonrecourse variable rate mortgage, due February 1, 2019	Sep. 01, 2012 Nonrecourse variable rate mortgage, due August 1, 2019	Dec. 03, 2011 Nonrecourse variable rate mortgage, due August 1, 2019	Sep. 01, 2012 Nonrecourse mortgages: 5.25%, due January 28, 2020	Dec. 03, 2011 Nonrecourse mortgages: 5.25%, due January 28, 2020	Sep. 01, 2012 Capital leases	Dec. 03, 2011 Capital leases	Jun. 30, 2012 Modification Agreement item	Sep. 01, 2012 Modification Agreement item	Jun. 07, 2012 Modification Agreement
Long-Term Debt
Interest rate (as a percent)							6.30%	6.30%	5.73%	5.73%	8.13%	8.13%	7.00%	7.00%					5.25%	5.25%				6.08%
Effectively fixed interest rate																									3.86%
Total	$ 60,002	$ 61,181	$ 59,922	$ 61,135	$ 6,756	$ 6,926	$ 335	$ 453	$ 19,115	$ 19,368	$ 4,024	$ 4,232	$ 6,073	$ 6,220	$ 11,455	$ 11,609	$ 8,074	$ 8,176	$ 4,090	$ 4,151	$ 80	$ 46
Less: current portion	(1,860)	(1,700)
Total long-term debt	$ 58,142	$ 59,481
Number of wholly-owned subsidiaries																							2
Basis of interest rate																								one month LIBOR
Interest rate added to the base rate (as a percent)																								2.75%
Amortization period of debt instrument																								25 years
Number of multi-story office buildings used as collateral for loan																								2