Supplemental Financial Statement Information (Details 3) (USD $) In Thousands, unless otherwise specified		0 Months Ended
May 31, 2014	Jan. 08, 2014 Imperial's landscape nursery business Inventory and certain assets item	Jun. 03, 2014 Imperial's landscape nursery business Inventory and certain assets Subsequent events
Discontinued operation
Proceeds from sale of nursery inventory		$ 732
Number of installments in which promissory note will become due		2
Amount of promissory note receivable due on June 1, 2014		2,750
Amount of promissory note receivable due on June 1, 2015		1,500
Discount rate (as a percent)		7.00%
Present value	4,036	4,036
Promissory Note installment received			$ 2,750

Represents the amount of installment of promissory note received by the entity.

No definition available.

Name:	grif_AmountOfInstallmentOfPromissoryNoteReceived
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of promissory note receivable by the entity on the first due date.

+ References

No definition available.

+ Details

Name:	grif_AmountOfPromissoryNoteReceivableOnFirstDueDate
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of promissory note receivable by the entity on the second due date.

+ References

No definition available.

+ Details

Name:	grif_AmountOfPromissoryNoteReceivableOnSecondDueDate
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the fair value of non-interest bearing note receivable, for the disposal group, including a component of the entity's (discontinued operation).

+ References

No definition available.

+ Details

Name:	grif_DisposalGroupIncludingDiscontinuedOperationNoteReceivableFairValue
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of cash inflow from the sale of nursery inventory.

+ References

No definition available.

+ Details

Name:	grif_ProceedsFromSaleOfInventory
Namespace Prefix:	grif_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the discount rate applied to non-interest bearing note receivable.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of installments in which the promissory note receivable by the entity will become due.

+ References

No definition available.

+ Details

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

- Details

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