COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Apr. 30, 2009 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Net capital cost value in proposed remedial action plan	$ 10,000

Amount of net capital cost value in Proposed Remedial Action Plan as of the reporting date.

No definition available.

Name:	gff_NetCapitalCostValueInProposedRemediaActionPlan
Namespace Prefix:	gff_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant