Aggregate Area of undeveloped Land.

No definition available.

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Balance Type:	na
Period Type:	instant

- Definition

Represents the estimated pretax gain on sale that would be recognized after all costs are incurred and total revenue is recognized.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Funds held in escrow for the acquisition of a replacement property, as a part of the Section 1031 like-kind exchange.

+ References

No definition available.

+ Details

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- Definition

Area of land sold.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of total cost incurred, related to the sale of real estate property.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Amount of real estate depreciation expense for the period.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Represents the percentage of revenue and pretax gain from sale of real estate property recognized based on the percentage of total costs incurred related to sale.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

This element represents the amount of deposit received in a land sale transaction.

+ References

No definition available.

+ Details

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Balance Type:	credit
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- Definition

Represents the sale price of land and related assets.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1 Response)

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

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- Definition

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2941-110230

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of interest capitalized during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Allowance for Funds Used during Construction

-URI http://asc.fasb.org/extlink&oid=6504829

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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Period Type:	duration

- Definition

Revenue from the sale of land in the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Useful life on which depreciation was computed for entities with a substantial portion of business acquiring and holding investment real estate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule III)

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 970

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-28)

-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

The cumulative amount of depreciation for real estate property held for investment purposes.

+ 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 210.7-03.1(3))

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

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ 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 210.7-03.1(d))

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

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Period Type:	instant

- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ 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 210.7-03.1(d))

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

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=grif_LandscapeNurseryMember
Namespace Prefix:
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- Details

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- Details

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis=grif_ImperialsFloridaFarmMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorPropertyClassAxis=us-gaap_LandMember
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Period Type:

- Details

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- Details

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- Details

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Real Estate Assets (Details) $ in Thousands		3 Months Ended		9 Months Ended		24 Months Ended
Real Estate Assets (Details) $ in Thousands	Jun. 01, 2015 USD ($)	Aug. 31, 2015 USD ($)	Aug. 31, 2014 USD ($)	Aug. 31, 2015 USD ($)	Aug. 31, 2014 USD ($)	Nov. 30, 2014 USD ($)	May. 31, 2015 USD ($)	Nov. 30, 2013 USD ($) a
Real Estate Assets
Real estate assets, gross		$ 235,980		$ 235,980		$ 209,284
Accumulated depreciation		(79,010)		(79,010)		(74,762)
Real estate assets, net		156,970		156,970		134,522
Depreciation expense		1,619	$ 1,459	4,765	$ 4,527
Capitalized interest		290	49	657	424
Sales
Deferred revenue		11,580		11,580		8,349
Imperial's landscape nursery business
Sales
Sale price		4,100		4,100			$ 4,100
Windsor undeveloped land sale
Sales
Revenue from sale of land				8,020
Pretax gain on land sale				6,111
Assets held for sale
Real Estate Assets
Real estate assets, net		9,963		9,963		9,943
Imperial's Florida farm \| Imperial's landscape nursery business
Sales
Deposit received in real estate sale	$ 400
Revenue from sale of land		400		400
Land
Real Estate Assets
Real estate assets, gross		$ 17,955		$ 17,955		17,955
Land \| Windsor undeveloped land sale
Sales
Number of acres sold \| a								90
Sale price								$ 9,000
Number of acres of undeveloped land \| a								253
Proceeds from land sale deposited in escrow								$ 8,860
Percentage of cost incurred on sale of land		89.00%		89.00%
Percentage of total revenue and pretax gain on sale have been recognized				89.00%
Revenue from sale of land		$ 1,176	904	$ 2,247	1,274
Pretax gain on land sale		1,014	$ 674	1,763	$ 950
Deferred revenue		948		948
Estimated pretax gain on sale that would be recognized after incurring total costs and recognizing total revenue				6,833		6,833
Land \| Assets held for sale
Real Estate Assets
Real estate assets, gross		286		286		286
Land improvements
Real Estate Assets
Real estate assets, gross		22,755		$ 22,755		18,527
Land improvements \| Minimum
Real Estate Assets
Estimated Useful Lives				10 years
Land improvements \| Maximum
Real Estate Assets
Estimated Useful Lives				30 years
Buildings and improvements
Real Estate Assets
Real estate assets, gross		147,480		$ 147,480		135,857
Buildings and improvements \| Minimum
Real Estate Assets
Estimated Useful Lives				10 years
Buildings and improvements \| Maximum
Real Estate Assets
Estimated Useful Lives				40 years
Tenant improvements
Real Estate Assets
Real estate assets, gross		19,570		$ 19,570		14,820
Machinery and equipment
Real Estate Assets
Real estate assets, gross		11,810		$ 11,810		11,810
Machinery and equipment \| Minimum
Real Estate Assets
Estimated Useful Lives				3 years
Machinery and equipment \| Maximum
Real Estate Assets
Estimated Useful Lives				20 years
Construction in progress
Real Estate Assets
Real estate assets, gross		9,104		$ 9,104		3,927
Development costs
Real Estate Assets
Real estate assets, gross		7,306		7,306		6,388
Development costs \| Assets held for sale
Real Estate Assets
Real estate assets, gross		$ 9,677		$ 9,677		$ 9,657