LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate					6.00%
Cash Interest	$ 11,730		$ 11,422		$ 34,795		$ 34,503
Amort. Debt Discount	846		777		2,491		2,286
Amort. Deferred Cost & Other Fees	703		733		2,160		2,211
Total Interest Expense	13,279		12,932		39,446		39,000
Senior Notes 2018 [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	7.40%	[1]	7.40%	[1]	7.40%	[1]	7.40%	[1]
Cash Interest	9,797	[1]	9,797	[1]	29,391	[1]	29,391	[1]
Amort. Debt Discount	0	[1]	0	[1]	0	[1]	0	[1]
Amort. Deferred Cost & Other Fees	406	[1]	406	[1]	1,217	[1]	1,218	[1]
Total Interest Expense	10,203	[1]	10,203	[1]	30,608	[1]	30,609	[1]
Revolver Due 2016 [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate		[1]		[1]	0.00%	[1]		[1]
Cash Interest	179	[1]	440	[1]	603	[1]	440	[1]
Amort. Debt Discount	0	[1]	0	[1]	0	[1]	0	[1]
Amort. Deferred Cost & Other Fees	131	[1]	157	[1]	444	[1]	466	[1]
Total Interest Expense	310	[1]	597	[1]	1,047	[1]	906	[1]
Convertible Debt 2017 [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	9.10%	[2]	9.20%	[2]	9.20%	[2]	9.20%	[2]
Cash Interest	1,000	[2]	1,000	[2]	3,000	[2]	3,000	[2]
Amort. Debt Discount	846	[2]	777	[2]	2,491	[2]	2,286	[2]
Amort. Deferred Cost & Other Fees	110	[2]	111	[2]	332	[2]	332	[2]
Total Interest Expense	1,956	[2]	1,888	[2]	5,823	[2]	5,618	[2]
Real Estate Mortgages Loan [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	4.90%	[3]	5.60%	[3]	4.90%	[3]	5.60%	[3]
Cash Interest	133	[3]	142	[3]	407	[3]	436	[3]
Amort. Debt Discount	0	[3]	0	[3]	0	[3]	0	[3]
Amort. Deferred Cost & Other Fees	22	[3]	22	[3]	65	[3]	65	[3]
Total Interest Expense	155	[3]	164	[3]	472	[3]	501	[3]
Employee Stock Ownership Plan Loan [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	2.80%	[4]	3.00%	[4]	2.90%	[4]	3.00%	[4]
Cash Interest	151	[4]	177	[4]	476	[4]	532	[4]
Amort. Debt Discount	0	[4]	0	[4]	0	[4]	0	[4]
Amort. Deferred Cost & Other Fees	2	[4]	2	[4]	6	[4]	4	[4]
Total Interest Expense	153	[4]	179	[4]	482	[4]	536	[4]
Capital Lease Obligations [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	5.30%	[5]	5.30%	[5]	5.30%	[5]	5.30%	[5]
Cash Interest	125	[5]	136	[5]	381	[5]	417	[5]
Amort. Debt Discount	0	[5]	0	[5]	0	[5]	0	[5]
Amort. Deferred Cost & Other Fees	6	[5]	6	[5]	19	[5]	19	[5]
Total Interest Expense	131	[5]	142	[5]	400	[5]	436	[5]
Term Loan 2013 [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	4.10%	[6]	3.40%	[6]	3.80%	[6]	4.80%	[6]
Cash Interest	58	[6]	164	[6]	232	[6]	691	[6]
Amort. Debt Discount	0	[6]	0	[6]	0	[6]	0	[6]
Amort. Deferred Cost & Other Fees	22	[6]	21	[6]	66	[6]	66	[6]
Total Interest Expense	80	[6]	185	[6]	298	[6]	757	[6]
Revolver Due 2013 [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate		[6]		[6]		[6]		[6]
Cash Interest	16	[6]	0	[6]	51	[6]	0	[6]
Amort. Debt Discount	0	[6]	0	[6]	0	[6]	0	[6]
Amort. Deferred Cost & Other Fees	0	[6]	0	[6]	0	[6]	0	[6]
Total Interest Expense	16	[6]	0	[6]	51	[6]	0	[6]
Foreign Line of Credit [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	13.60%	[7]	15.00%	[7]	12.00%	[7]	9.80%	[7]
Cash Interest	139	[7]	26	[7]	364	[7]	182	[7]
Amort. Debt Discount	0	[7]	0	[7]	0	[7]	0	[7]
Amort. Deferred Cost & Other Fees	0	[7]	0	[7]	0	[7]	0	[7]
Total Interest Expense	139	[7]	26	[7]	364	[7]	182	[7]
Foreign Term Loan [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Effective Interest Rate	10.80%	[7]	10.90%	[7]	10.50%	[7]	10.60%	[7]
Cash Interest	51	[7]	101	[7]	183	[7]	151	[7]
Amort. Debt Discount	0	[7]	0	[7]	0	[7]	0	[7]
Amort. Deferred Cost & Other Fees	4	[7]	8	[7]	11	[7]	7	[7]
Total Interest Expense	55	[7]	109	[7]	194	[7]	158	[7]
Other Long Term Debt [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Cash Interest	272	[8]	30	[8]	523	[8]	785	[8]
Amort. Debt Discount	0	[8]	0	[8]	0	[8]	0	[8]
Amort. Deferred Cost & Other Fees	0	[8]	0	[8]	0	[8]	34	[8]
Total Interest Expense	272	[8]	30	[8]	523	[8]	819	[8]
Capitalized Interest [Member]
LONG-TERM DEBT (Details) - Summary of Interest Expense Incurred [Line Items]
Cash Interest	(191)		(591)		(816)		(1,522)
Amort. Debt Discount	0		0		0		0
Amort. Deferred Cost & Other Fees	0		0		0		0
Total Interest Expense	$ (191)		$ (591)		$ (816)		$ (1,522)

[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 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 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 28, 2013, Griffon amended and increased the amount available under its Revolving Credit Facility ("Credit Agreement") from $200,000 to $225,000 and extended its maturity from March 17, 2016 to March 28, 2018. The facility includes a letter of credit sub-facility with a limit of $60,000, 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 an event of default under the Credit Agreement. Interest is payable on borrowings at either a LIBOR or base rate benchmark rate, in each case without a floor, plus an applicable margin, which adjusts based on financial performance. The current margins are 1.25% for base rate loans and 2.25% for LIBOR loans. 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 Griffon's material domestic subsidiaries and are secured, on a first priority basis, by substantially all assets of the Company and the guarantors.At June 30, 2013, there were $25,867 of standby letters of credit outstanding under the Credit Agreement; $199,133 was available, subject to certain covenants, for borrowing at that date.

[2] On December 21, 2009, Griffon issued $100,000 principal of 4% convertible subordinated notes due 2017 (the "2017 Notes"). The current conversion rate of the 2017 Notes is 67.8495 shares of Griffon's common stock per $1,000 principal amount of notes, corresponding to a conversion price of $14.74 per share. When a cash dividend is declared that would result in an adjustment to the conversion ratio of less than 1%, any adjustment to the conversion ratio is deferred until the first to occur of (i) actual conversion, (ii) the 42nd trading day prior to maturity of the notes, and (iii) such time as the cumulative adjustment equals or exceeds 1%. As of June 30, 2013, aggregate dividends since the last conversion price adjustment of $0.05 per share would have resulted in an adjustment to the conversion ratio of approximately 0.44%. At June 30, 2013 and September 30, 2012, the 2017 Notes had a capital in excess of par component, net of tax, of $15,720.

[3] On December 20, 2010, Griffon entered into two second lien real estate mortgages to secure new loans totaling $11,834. The loans mature in February 2016, are collateralized by the related properties and are guaranteed by Griffon. The loans bear interest at a rate of LIBOR plus 3% with the option to swap to a fixed rate.Griffon has other real estate mortgages, collateralized by real property, which bear interest at 6.3% and mature in 2016.

[4] Griffon's Employee Stock Ownership Plan ("ESOP") entered into a loan agreement in August 2010 to borrow $20,000 over a one-year period. The proceeds were used to purchase 1,874,737 shares of Griffon common stock in the open market for $19,973. The loan bears interest at a) LIBOR plus 2.5% or b) the lender's prime rate, at Griffon's option. In November 2011, Griffon exercised an option to convert the outstanding loan to a five-year term loan; principal is payable in quarterly installments of $250, beginning December 2011, with a balloon payment of $15,223 due at maturity (November 2016). The loan is secured by shares purchased with the proceeds of the loan, and repayment is guaranteed by Griffon. At June 30, 2013, $18,223 was outstanding.In addition, the ESOP is party to a loan agreement which requires quarterly principal payments of $156 and interest through the extended expiration date of December 2013 at which time the $3,125 balance of the loan, and any outstanding interest, will be payable. Griffon has the intent and ability to refinance the December 2013 balance, and has classified the balance in Long-Term Debt. The primary purpose of this loan was to purchase 547,605 shares of Griffon's common stock in October 2008. The loan is secured by shares purchased with the proceeds of the loan, and repayment is guaranteed by Griffon. The loan bears interest at rates based upon the prime rate or LIBOR. At June 30, 2013, $3,281 was outstanding.

[5] In October 2006, CBP entered into a capital lease totaling $14,290 for real estate in Troy, Ohio. The lease matures in 2021, bears interest at a fixed rate of 5.3%, is secured by a mortgage on the real estate and is guaranteed by Griffon.

[6] In November 2010, Clopay Europe GMBH ("Clopay Europe") entered into a 10,000 revolving credit facility and a 20,000 term loan. The facility accrues interest at EURIBOR plus 2.45% per annum and the term loan accrues interest at EURIBOR plus 2.20% per annum. The revolving facility matures in November 2013, but is renewable upon mutual agreement with the bank. In July 2011, the full 20,000 was drawn on the Term Loan, with a portion of the proceeds used to repay borrowings under the revolving credit facility. The term loan is payable in ten equal quarterly installments which began in September 2011, with maturity in December 2013. Under the term loan, Clopay Europe is required to maintain a certain minimum equity to assets ratio and keep leverage below a certain level, defined as the ratio of total debt to EBITDA.

[7] In February 2012, Clopay do Brazil, a subsidiary of Plastics, borrowed $4,000 at a rate of 104.5% of Brazilian CDI (7.7% at June 30, 2013). The loan was used to refinance existing loans, is collateralized by accounts receivable and a 50% guaranty by Plastics and is to be repaid in four equal, semi-annual installments of principal plus accrued interest beginning in August 2012. Clopay do Brazil also maintains lines of credit of approximately $5,000.Interest on borrowings accrue at a rate of Brazilian CDI plus 6.0% (13.7%, at June 30, 2013). At June 30, 2013 there was approximately $4,100 borrowed under the lines.In November 2012, Garant G.P. ("Garant") entered into a CAD $15,000 revolving credit facility. The facility accrues interest at LIBOR or the Bankers Acceptance Rate plus 1.3% per annum (1.49% and 2.45% as of June 30, 2013). The revolving facility matures in November 2015. Garant is required to maintain a certain minimum equity. At June 30, 2013, there were 0 borrowings under the revolving credit facility with CAD $15,000 available for borrowing.

[8] At September 30, 2012, Griffon had $532 of 4% convertible subordinated notes due 2023 ("2023 Notes") outstanding. On April 15, 2013, the 2023 Notes were redeemed at par plus accrued interest. Other long term debt also includes capital leases.