Effect on Future EBITDA Margins, Percentage

No definition available.

Name:	gff_EffectOnFutureEBITDAMarginsPercentage
Namespace Prefix:	gff_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Restructuring and Related Cost, Expected Reduction In Inventory

+ References

No definition available.

+ Details

Name:	gff_RestructuringAndRelatedCostExpectedReductionInInventory
Namespace Prefix:	gff_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The quantified amount of the future effect on cash flows.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.P.4)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_EffectOnFutureCashFlowsAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount expected to be recognized in earnings for the specified restructuring cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(d))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringAndRelatedCostExpectedCost1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of positions eliminated during the period as a result of restructuring activities.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109237686&loc=d3e17752-110868

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

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

- Definition

Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

+ Details

Name:	us-gaap_RestructuringCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of decrease in the reserve for full or partial settlement through consideration other than cash.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(2))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringReserveSettledWithoutCash2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=gff_ConsumerAndProfessionalProductsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=gff_NextGenerationBusinessPlatformMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=gff_OneTimeChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=gff_CapitalInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=gff_EmployeeSeveranceAndFacilityClosingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_EmployeeSeveranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_FacilityClosingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=gff_AssetWriteDownsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

RESTRUCTURING CHARGES - Narrative (Details) $ in Thousands		3 Months Ended
RESTRUCTURING CHARGES - Narrative (Details) $ in Thousands	Nov. 12, 2020 USD ($)	Dec. 31, 2021 USD ($) position	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 1,716		$ 3,079
Non-cash charges			$ 289
Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring charges				3,079
Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring costs		1,427		2,886
Non-cash charges		$ 289		193
Reduction of headcount \| position		0
Minimum \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Effects on EBITDA margin	0.12
Annual cash savings	$ 30,000
Reduction in inventory	30,000
Maximum \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Annual cash savings	35,000
Reduction in inventory	35,000
One-time charges \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	65,000
Capital investments \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	65,000
Cash charges \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	46,000
Personnel related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 260		362
Non-cash charges			0
Personnel related costs \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	26,000
Restructuring costs		260		362
Facilities & Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,167		2,524
Non-cash charges			$ 0
Facilities & Exit Costs \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	20,000
Restructuring costs		$ 1,167		$ 2,524
Asset write-downs \| Next-generation Business Platform \| Consumer and Professional Products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 19,000