The increase (decrease) in estimated project cost during the period.

No definition available.

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Balance Type:	debit
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- Definition

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

+ References

No definition available.

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Balance Type:	debit
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- Definition

The total pre-tax gain (loss) estimated to be derived from the project over its entire life.

+ References

No definition available.

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Namespace Prefix:	grif_
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Balance Type:	debit
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- Definition

The number of acres donated by the entity.

+ References

No definition available.

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The number of acres retained by the entity.

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No definition available.

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- Definition

Area of land sold.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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The price for which the property subject to or available for an operating lease may be purchased under the purchase option conditions.

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No definition available.

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Amount of real estate depreciation expense for the period.

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No definition available.

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The total gross cost at balance sheet date of construction on real estate projects that are not yet completed.

+ References

No definition available.

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Amount of real estate investment property not held for sale, which may include the following: (1) land available-for-development; (2) investments in building and building improvements; (3) tenant allowances; (4) developments in-process; (5) rental properties; and (6) other real estate investments.

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No definition available.

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Amount of real estate investment property not including that held for sale, net of accumulated depreciation, which may include the following: (1) land available-for-development; (2) investments in building and building improvements; (3) tenant allowances; (4) developments in-process; (5) rental properties; and (6) other real estate investments.

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No definition available.

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- Definition

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

+ References

No definition available.

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Data Type:	num:percentItemType
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- Definition

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

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No definition available.

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- Definition

Represents the sale price of land and related assets.

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No definition available.

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- Definition

Area of land held.

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No definition available.

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- 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.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Paragraph 1
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- Definition

The current amount of expenditures for a real estate project that has not yet been completed.

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- Definition

Amount before accumulated depreciation of fixtures and equipment. Includes, but is not limited to, machinery, equipment, and engines.

+ References

No definition available.

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

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Amount of interest capitalized during the period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.

+ References

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Paragraph 1
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Amount before accumulated deprecation and depletion of additions or improvements to real estate held for productive use. Examples include, but are not limited to, walkways, driveways, fences, and parking lots.

+ References

No definition available.

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- Definition

Term of the lessor's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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The cash inflow from the sale of land held for investment; excludes sales of land held as inventory or productive use.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

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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.

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-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule III)
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28)
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- References

No definition available.

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Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

+ References

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

+ References

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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.

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No definition available.

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Revenue from the sale of commercial, industrial, or residential property during the period. This element is more likely than not relevant to an entity for which real estate operations are a principal activity. If real estate operations are not a principal activity, the reporting entity would likely use a gain (loss) on sale of property, plant, or equipment type element.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Carrying amount as of the balance sheet date of improvements having a life longer than one year that were made for the benefit of one or more tenants.

+ References

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Real Estate Assets (Details) $ in Thousands			1 Months Ended	3 Months Ended			12 Months Ended
Real Estate Assets (Details) $ in Thousands	Sep. 22, 2016 USD ($) a	Jun. 01, 2015 USD ($)	Aug. 31, 2015 USD ($)	May 31, 2016 USD ($)	Feb. 29, 2016 USD ($)	Nov. 30, 2013 USD ($) a	Nov. 30, 2016 USD ($)	Nov. 30, 2015 USD ($)	Nov. 30, 2014 USD ($)	Nov. 30, 2013 USD ($) a	May 31, 2015 USD ($)
Real Estate Assets
Land							$ 17,895	$ 18,157
Land improvements							27,592	22,440
Buildings and improvements							164,353	149,111
Tenant improvements							21,925	19,611
Machinery and equipment							11,022	11,810
Construction in progress							1,659	10,240
Development costs							14,615	15,870
Real estate assets, gross							259,061	247,239
Accumulated depreciation							(86,801)	(80,784)
Real estate assets, net							172,260	166,455
Depreciation expense							7,768	6,539	$ 5,747
Capitalized interest							274	777	580
Sales
Revenue from property sales							4,364	3,483	3,667
Deferred revenue							9,526	10,790
Real estate held for sale							$ 2,992	1,418
Maximum
Sales
Purchase price under option			$ 3,900
Windsor undeveloped land sale
Sales
Number of acres sold \| a						90				90
Proceeds from sale of undeveloped land						$ 8,968
Number of acres \| a						268				268
Proceeds from land sale deposited in escrow						$ 8,860
Increase in estimated project cost				$ 79
Percentage of cost incurred on sale of land							99.00%
Revenue from property sales							$ 608	2,483	3,105	$ 2,668
Estimated total pre-tax gain					$ 6,765		6,686
Pretax gain on land sale							380	1,880	$ 2,358	$ 1,990
Number of acres donated \| a						15				15
Griffin Center South, Bloomfield, CT
Sales
Number of acres sold \| a	29
Number of acres \| a	45
Proceeds from land sale deposited in escrow	$ 3,536
Revenue from property sales	3,756
Pretax gain on land sale	$ 3,174
Number of acres donated \| a	15
Number of acres retained \| a	1
Florida Farm Used By Imperial [Member]
Sales
Revenue from property sales								400
Sale price											$ 4,100
Deposit received in real estate sale		$ 400
Lease term			3 years
Florida Farm Used By Imperial [Member] \| Minimum
Sales
Purchase price under option			$ 3,400
Land.
Sales
Real estate held for sale							$ 264	78
Land. \| Windsor undeveloped land sale
Sales
Percentage of total revenue and pretax gain on sale have been recognized							99.00%
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 \| Minimum
Real Estate Assets
Estimated Useful Lives							10 years
Buildings and improvements \| Maximum
Real Estate Assets
Estimated Useful Lives							40 years
Machinery and equipment. \| Minimum
Real Estate Assets
Estimated Useful Lives							3 years
Machinery and equipment. \| Maximum
Real Estate Assets
Estimated Useful Lives							20 years
Development costs
Sales
Real estate held for sale							$ 2,728	$ 1,340