Name:	grif_EstimatedPretaxGainFromSaleOfRealEstatePropertyToBeRecognizedAfterIncurringTotalCostsAndRecognitionOfTotalRevenue
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

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

No definition available.

Name:	grif_PercentageOfTotalCostsIncurredRelatedToSaleOfRealEstateProperty
Namespace Prefix:	grif_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

No definition available.

Name:	grif_PretaxGainFromSaleOfRealEstatePropertyRecognizedBasedOnPercentageOfTotalCostsIncurredRelatedToSale
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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.

No definition available.

Name:	grif_RealEstatePropertiesPercentageOfRevenueAndPretaxGainOnSaleOfLandRecognized
Namespace Prefix:	grif_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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.

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

Reference 2: 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)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

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

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2941-110230

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Name:	us-gaap_GainLossOnDispositionOfAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Revenue from the sale of land in the reporting period.

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