RELATED PARTIES (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 Senior Notes [Member]		Sep. 30, 2011 Senior Notes [Member]
Debt Instrument, Interest Rate at Period End			7.125%	[1]	7.125%	[1]
Costs and Expenses, Related Party	$ 825	$ 14,149

[1] On March 17, 2011, in an unregistered offering through a private placement under Rule 144A, Griffon issued, at par, $550,000 of 7.125% Senior Notes due in 2018 ("Senior Notes"); interest is payable semi-annually. On August 9, 2011, Griffon exchanged all of the Senior Notes for substantially identical Senior Notes registered under the Securities Act of 1933 ("Senior Notes"), via an exchange offer.The Senior Notes can be redeemed prior to April 1, 2014 at a price of 100% of principal plus a make-whole premium and accrued interest; on or after April 1, 2014, the Senior Notes can be redeemed at a certain price (declining from 105.344% of principal on or after April 1, 2014 to 100% of principal on or after April 1, 2017), plus accrued interest. Proceeds from the Senior Notes were used to pay down the outstanding borrowings under a senior secured term loan facility and two senior secured revolving credit facilities of certain of the Company's subsidiaries. The Senior Notes are senior unsecured obligations of Griffon guaranteed by certain domestic subsidiaries, and are subject to certain covenants, limitations and restrictions.On March 18, 2011, Griffon entered into a five-year $200,000 Revolving Credit Facility ("Credit Agreement"), which included a letter of credit sub-facility with a limit of $50,000, a multi-currency sub-facility of $50,000 and a swingline sub-facility with a limit of $30,000. Borrowings under the Credit Agreement may be repaid and re-borrowed at any time, subject to final maturity of the facility or the occurrence of a default or event of default under the Credit Agreement. Interest is payable on borrowings at either a LIBOR or base rate benchmark rate plus an applicable margin, which adjusts based on financial performance. The margins are 1.75% for base rate loans and 2.75% for LIBOR loans, in each case without a floor. The Credit Agreement has certain financial maintenance tests including a maximum total leverage ratio, a maximum senior secured leverage ratio and a minimum interest coverage ratio as well as customary affirmative and negative covenants and events of default. The Credit Agreement also includes certain restrictions, such as limitations on the incurrence of indebtedness and liens and the making of restricted payments and investments. Borrowings under the Credit Agreement are guaranteed by certain domestic subsidiaries and are secured, on a first priority basis, by substantially all assets of the Company and the guarantors.At September 30, 2012, there were $21,693 of standby letters of credit outstanding under the Credit Agreement; $178,307 was available for borrowing at that date.