LONG-TERM DEBT (Details) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended				6 Months Ended		12 Months Ended							6 Months Ended			6 Months Ended		6 Months Ended		12 Months Ended		3 Months Ended				6 Months Ended							3 Months Ended				6 Months Ended						6 Months Ended	3 Months Ended				6 Months Ended						3 Months Ended				6 Months Ended						3 Months Ended	6 Months Ended	12 Months Ended	3 Months Ended				6 Months Ended				12 Months Ended			12 Months Ended		3 Months Ended				6 Months Ended						3 Months Ended						6 Months Ended
	Dec. 31, 2013 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2012	Mar. 31, 2014 USD ($)	Mar. 31, 2013 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2007	Oct. 21, 2013 USD ($)	Sep. 30, 2013 USD ($)	Mar. 31, 2014 Letter Of Credit Subfacility [Member] Revolver Due 2019 [ Member] USD ($)	Feb. 14, 2014 Letter Of Credit Subfacility [Member] Revolver Due 2019 [ Member] USD ($)	Feb. 14, 2014 Multicurrency Subfacility [Member] Revolver Due 2019 [ Member] USD ($)	Mar. 31, 2014 Swingline Subfacility [Member] Revolver Due 2019 [ Member] USD ($)	Mar. 31, 2014 Margin Rate [Member] Revolver Due 2019 [ Member]	Mar. 31, 2014 LIBOR Rate [Member] Foreign Line of Credit [Member]	Mar. 31, 2014 LIBOR Rate [Member]	Mar. 31, 2014 Bankers Acceptance Rate [Member] Foreign Line of Credit [Member]	Mar. 31, 2014 Convertible Debt 2017 [Member] USD ($)	Mar. 31, 2013 Convertible Debt 2017 [Member] USD ($)	Sep. 30, 2010 Convertible Debt 2017 [Member]	Dec. 21, 2009 Convertible Debt 2017 [Member] USD ($)	Mar. 31, 2014 Senior Notes 2022 [Member] USD ($)		Mar. 31, 2013 Senior Notes 2022 [Member] USD ($)		Mar. 31, 2014 Senior Notes 2022 [Member] USD ($)		Mar. 31, 2013 Senior Notes 2022 [Member] USD ($)		Feb. 27, 2014 Senior Notes 2022 [Member] USD ($)	Sep. 30, 2013 Senior Notes 2022 [Member] USD ($)		Mar. 31, 2014 Senior Notes 2018 [Member] USD ($)		Mar. 31, 2013 Senior Notes 2018 [Member] USD ($)		Mar. 31, 2014 Senior Notes 2018 [Member] USD ($)		Mar. 31, 2013 Senior Notes 2018 [Member] USD ($)		Sep. 30, 2013 Senior Notes 2018 [Member] USD ($)		Mar. 31, 2014 Senior Notes [Member] USD ($)	Mar. 31, 2014 Real Estate Mortgages Loan [Member] USD ($)		Mar. 31, 2013 Real Estate Mortgages Loan [Member] USD ($)		Mar. 31, 2014 Real Estate Mortgages Loan [Member] USD ($)		Mar. 31, 2013 Real Estate Mortgages Loan [Member] USD ($)		Sep. 30, 2013 Real Estate Mortgages Loan [Member] USD ($)		Mar. 31, 2014 Employee Stock Ownership Plan Loan [Member] USD ($)		Mar. 31, 2013 Employee Stock Ownership Plan Loan [Member] USD ($)		Mar. 31, 2014 Employee Stock Ownership Plan Loan [Member] USD ($)		Mar. 31, 2013 Employee Stock Ownership Plan Loan [Member] USD ($)		Sep. 30, 2013 Employee Stock Ownership Plan Loan [Member] USD ($)		Dec. 31, 2013 Term Loan [Member] AUD	Mar. 31, 2014 Term Loan [Member] USD ($)	Sep. 30, 2011 Term Loan [Member] EUR (€)	Mar. 31, 2014 Capital Lease Obligations [Member] USD ($)		Mar. 31, 2013 Capital Lease Obligations [Member] USD ($)		Mar. 31, 2014 Capital Lease Obligations [Member] USD ($)		Mar. 31, 2013 Capital Lease Obligations [Member] USD ($)		Sep. 30, 2007 Capital Lease Obligations [Member] USD ($)	Sep. 30, 2013 Capital Lease Obligations [Member] USD ($)		Sep. 30, 2011 Revolver Due 2013 [Member] EUR (€)	Mar. 31, 2014 Foreign Term Loan [Member] Brazilian CDI [Member]	Mar. 31, 2014 Foreign Term Loan [Member] USD ($)		Mar. 31, 2013 Foreign Term Loan [Member] USD ($)		Mar. 31, 2014 Foreign Term Loan [Member] USD ($)		Mar. 31, 2013 Foreign Term Loan [Member] USD ($)		Sep. 30, 2013 Foreign Term Loan [Member] USD ($)		Mar. 31, 2014 Foreign Line of Credit [Member] USD ($)		Dec. 31, 2013 Foreign Line of Credit [Member]	Mar. 31, 2013 Foreign Line of Credit [Member] USD ($)		Dec. 31, 2012 Foreign Line of Credit [Member] CAD	Mar. 31, 2014 Foreign Line of Credit [Member] USD ($)		Mar. 31, 2013 Foreign Line of Credit [Member] USD ($)		Mar. 31, 2014 Foreign Line of Credit [Member] CAD	Sep. 30, 2013 Foreign Line of Credit [Member] USD ($)		Mar. 31, 2014 Revolver Due 2019 [ Member] USD ($)	Feb. 14, 2014 Revolver Due 2019 [ Member] USD ($)
LONG-TERM DEBT (Details) [Line Items]
Debt Instrument, Face Amount	$ 21,098		$ 21,098							$ 17,175													$ 100,000									$ 600,000			$ 550,000				$ 550,000																											12,500
Debt Instrument, Interest Rate, Stated Percentage																							4.00%									5.25%			7.125%				7.125%
Payment of Tender Offer Premium						31,530
Interest Paid		10,807		11,497		22,335	23,065																	2,800	[1]	0	[1]	2,800	[1]	0	[1]				6,133	[1]	9,797	[1]	15,930	[1]	19,594	[1]			16,716	122	[2]	135	[2]	252	[2]	274	[2]			180	[3]	158	[3]	332	[3]	325	[3]						114	[4]	125	[4]	233	[4]	256	[4]						101	[5]	133	[5]	153	[5]	306	[5]			224	[5]		147	[5]		417	[5]	260	[5]
Underwriting Fees and Other Expense Capitalized						9,950
Gains (Losses) on Extinguishment of Debt		(38,890)				(38,890)
Write off of Deferred Debt Issuance Cost						6,574
Prepaid Interest on Defeased Note on Extinguishment of Debt						786
Line of Credit Facility, Current Borrowing Capacity													60,000	50,000																																																																														2,800						2,800				15,000				225,000
Proceeds from Lines of Credit															30,000
Line of Credit Facility, Interest Rate During Period																1.25%		2.25%
Maximum Percentage of Equity Interest of Subsidiaries Borrowings Guaranteed						65.00%
Line of Credit Facility, Amount Outstanding		0				0		5,500				20,352																																																							11,559															3,943				3,943																			20,000
Line of Credit Facility, Remaining Borrowing Capacity																																																																																																									184,648
Debt Instrument, Convertible, Conversion Ratio																				68.6238
Debt Conversion, Converted Instrument, Amount																				1,000
Debt Instrument, Convertible, Conversion Price (in Dollars per share)																				$ 14.57
Debt Instrument, Convertible, Terms of Conversion Feature																						1%
Debt Instrument, Convertible, If-converted Value in Excess of Principal																				15,720	15,720
Number of Properties Refinanced										2
Debt Instrument, Maturity Date						Oct. 31, 2018																																																													Dec. 31, 2018
Debt Instrument, Description of Variable Rate Basis								The revolving credit facility accrues interest at EURIBOR plus 2.20% per annum																																										The loans bear interest at a rate of LIBOR plus 2.75%.										The loan bears interest at a) LIBOR plus 2.25% or b) the lender's prime rate, at Griffon's option.
Debt Instrument, Basis Spread on Variable Rate					1.30%	2.20%																																												2.75%										2.25%						2.80%																										4.95%		2.25%
Long-term Debt, Gross		798,426				798,426					702,501													600,000	[1]			600,000	[1]				0	[1]	0	[1]			0	[1]			550,000	[1]		16,818	[2]			16,818	[2]			13,212	[2]	30,087	[3]			30,087	[3]			21,098	[3]				9,042	[4]			9,042	[4]				9,529	[4]			11,559	[5]			11,559	[5]			3,115	[5]	9,443	[5]					9,443	[5]				4,606	[5]
Number of Refinanced ESOP Loan	2
Number of New Term Loan Refinance from ESOP Loans	1
Amount of Line Note Available to Purchase Common Stock in Open Market			10,000
Share-based Compensation Arrangement by Share-based Payment Award, Shares Purchased for Award (in Shares)						749,977
Share Based Compensation Arrangement by Share Based Payment Award Shares Purchased for Award Value						10,000
Debt Instrument, Periodic Payment, Principal						419																																																						505
Debt Instrument Balloon Payment																																																												19,000
Proceeds from Issuance of Long-term Debt						644,514	303																																																																						14,290
Capital Lease Maturity Year									2022
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate									5.00%
Proceeds from Long-term Lines of Credit																																																																				20,000												10,000																	15,000
Line of Credit Facility, Expiration Date						Nov. 30, 2014
Maintains Maximum Amount Of Line Of Credit																																																																																		$ 5,700				$ 5,700
Debt Instrument, Interest Rate During Period						6.00%																		5.30%	[1]		[1]	5.30%	[1]		[1]				7.10%	[1]	7.50%	[1]	7.10%	[1]	7.40%	[1]				3.80%	[2]	5.40%	[2]	4.00%	[2]	5.40%	[2]			3.40%	[3]	2.90%	[3]	3.20%	[3]	2.90%	[3]						5.30%	[4]	5.20%	[4]	5.30%	[4]	5.30%	[4]							[5]		[5]		[5]		[5]				[5]			[5]			[5]		[5]
Line of Credit Facility, Interest Rate at Period End																	1.45%		2.47%																																																														16.55%
Line of Credit Facility, Interest Rate Description																																																																																																	The facility accrues interest at LIBOR (USD) or the Bankers Acceptance Rate (CDN) plus 1.3% per annum
Term Loan Maturity Period																																																																		Dec. 31, 2016
Debt Instrument, Interest Rate at Period End																								5.25%	[1]			5.25%	[1]					[1]		[1]				[1]			7.10%	[1]			[2]				[2]				[2]		[3]				[3]				[3]		5.50%		5.00%	[4]			5.00%	[4]				5.00%	[4]				[5]				[5]				[5]		[5]						[5]					[5]

[1] On February 27, 2014, in an unregistered offering through a private placement under Rule 144A, Griffon issued, at par, $600,000 of 5.25% Senior Notes due 2022 ("Senior Notes"); interest is payable semi-annually on March 1 and September 1, starting September 1, 2014. Proceeds from the Senior Notes were used to redeem $550,000 of 7.125% senior notes due 2018, to pay a tender offer premium of $31,530 and to make interest payments of $16,716, with the balance used to pay a portion of the related fees and expenses. The Senior Notes are senior unsecured obligations of Griffon guaranteed by certain domestic subsidiaries, and subject to certain covenants, limitations and restrictions. At the time of issuance of the Senior Notes, Griffon agreed that, within certain time periods after the issue date, it would offer to each noteholder, pursuant to a registration statement filed with and to be declared effective by the SEC, the opportunity to exchange its Senior Notes for new notes that have substantially identical terms to those of the Senior Notes (the only material difference being that the new notes are registered with the SEC). In connection with these transactions, Griffon capitalized $9,950 of underwriting fees and other expenses incurred related to issuance of the Senior Notes, which will amortize over the term of such notes. Griffon recognized a loss on the early extinguishment of debt on the 7.125% senior notes aggregating $38,890, comprised of the $31,530 tender offer premium, the write-off of $6,574 of remaining deferred financing fees and $786 of prepaid interest on defeased notes.On February 14, 2014, Griffon amended its $225,000 Revolving Credit Facility ("Credit Agreement") extending its maturity date from March 28, 2018 to March 28, 2019, amending certain financial maintenance ratio test thresholds and increasing certain baskets for permitted debt, guaranties, liens, asset sales, foreign acquisitions, investments and restricted payments. 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 swing line 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 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 ability of Griffon to incur indebtedness and liens and to make 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 and a pledge of not greater than 65% of the equity interest in each of Griffon's material, first-tier foreign subsidiaries.At March 31, 2014, outstanding borrowings and standby letters of credit were $20,000 and $20,352, respectively; $184,648 was available for borrowing at that date.

[2] On October 21, 2013, Griffon refinanced two properties' real estate mortgages to secure new loans totaling $17,175. The loans mature in October 2018, are collateralized by the related properties and are guaranteed by Griffon. The loans bear interest at a rate of LIBOR plus 2.75%. At March 31, 2014, $16,818 was outstanding.

[3] In December 2013, Griffon's Employee Stock Ownership Plan ("ESOP") entered into an agreement which refinanced the two existing ESOP loans into one new Term Loan in the amount of $21,098. The Agreement also provided a Line Note with $10,000 available to purchase shares of Griffon common stock in the open market through September 29, 2014. As of March 31, 2014, 749,977 shares of Griffon common stock, for a total of $10,000, were purchased with proceeds from the Line Note. In March 2014, the Line Note was combined with the Term Loan to form one new term loan. The loan bears interest at a) LIBOR plus 2.25% or b) the lender's prime rate, at Griffon's option. The loan requires quarterly principal payments of $505 through September 30, 2014 and $419 per quarter thereafter, with a balloon payment of approximately $19,000 due at maturity in December 2018. The loan is secured by shares purchased with the proceeds of the loan and with a lien on a specific amount of Griffon assets, and Griffon guarantees repayment. As of March 31, 2014, approximately $30,087 was outstanding.

[4] In October 2006, CBP entered into a capital lease totaling $14,290 for real estate in Troy, Ohio. The lease matures in 2022, bears interest at a fixed rate of 5.0%, is secured by a mortgage on the real estate and is guaranteed by Griffon.

[5] In November 2010, Clopay Europe GMBH ("Clopay Europe") entered into a 10,000 revolving credit facility and a 20,000 term loan. The term loan was paid off in December 2013 and the revolver had borrowings of $5,500 at March 31, 2014. The revolving facility matures in November 2014, but is renewable upon mutual agreement with the bank. The revolving credit facility accrues interest at EURIBOR plus 2.20% per annum. 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.Clopay do Brazil maintains lines of credit of approximately $5,700. Interest on borrowings accrues at a rate of Brazilian CDI plus 6.0% (16.55% at March 31, 2014). At March 31, 2014 there was approximately $3,943 borrowed under the lines. Clopay Plastic Products Co., Inc. guarantees the loan and lines.In November 2012, Garant G.P. ("Garant") entered into a CAD $15,000 revolving credit facility. The facility accrues interest at LIBOR (USD) or the Bankers Acceptance Rate (CDN) plus 1.3% per annum (1.45% LIBOR USD and 2.47% Bankers Acceptance Rate CDN as of March 31, 2014). The revolving facility matures in November 2015. Garant is required to maintain a certain minimum equity. At March 31, 2014, there were 0 borrowings under the revolving credit facility with CAD $15,000 available for borrowing.In December 2013, Northcote Holdings Pty. Ltd entered into an AUD $12,500 term loan. The term loan is unsecured, requires quarterly interest payments and principal is due at maturity (December 2016). The loan accrues interest at Bank Bill Swap Bid Rate "BBSY" plus 2.8% per annum (5.5% at March 31, 2014). As of March 31, 2014, Griffon had an outstanding balance of $11,559. Subsidiaries of Northcote Holdings maintain a line of credit of approximately $2,800. The line of credit accrues interest at BBSY plus 2.25% per annum (4.95% at March 31, 2014). At March 31, 2014, there were no outstanding borrowings under the line. Griffon Corporation guarantees both the term loan and the line of credit.