DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)	9 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, these financial statements do not include all the information and footnotes required by U.S. GAAP for complete financial statements. As such, they should be read with reference to Griffon’s Annual Report on Form 10-K for the year ended September 30, 2013, which provides a more complete explanation of Griffon’s accounting policies, financial position, operating results, business properties and other matters. In the opinion of management, these financial statements reflect all adjustments considered necessary for a fair statement of interim results. Griffon’s HBP operations are seasonal; for this and other reasons, the financial results of the Company for any interim period are not necessarily indicative of the results for the full year. The condensed consolidated balance sheet information at September 30, 2013 was derived from the audited financial statements included in Griffon’s Annual Report on Form 10-K for the year ended September 30, 2013. The consolidated financial statements include the accounts of Griffon and all subsidiaries. Intercompany accounts and transactions have been eliminated on consolidation. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting periods. These estimates may be adjusted due to changes in economic, industry or customer financial conditions, as well as changes in technology or demand. Significant estimates include allowances for doubtful accounts receivable and returns, net realizable value of inventories, restructuring reserves, valuation of goodwill and intangible assets, percentage of completion method of accounting, pension assumptions, useful lives associated with depreciation and amortization of intangible and fixed assets, warranty reserves, sales incentive accruals, stock based compensation assumptions, income taxes and tax valuation reserves, environmental reserves, legal reserves, insurance reserves and the valuation of discontinued assets and liabilities, and the accompanying disclosures. These estimates are based on management’s best knowledge of current events and actions Griffon may undertake in the future. Actual results may ultimately differ from these estimates. Certain amounts in the prior year have been reclassified to conform to current year presentation.
Inventory	Inventories are stated at the lower of cost (first-in, first-out or average) or market.
Share-based Compensation, Option and Incentive Plans	Compensation expense for restricted stock is recognized ratably over the required service period based on the fair value of the grant calculated as the number of shares granted multiplied by the stock price on the date of grant and, for performance shares, the likelihood of achieving the performance criteria. Compensation cost related to stock-based awards with graded vesting is amortized using the straight-line attribution method.
New Accounting Pronouncements	In February 2013, the FASB issued guidance requiring enhanced disclosures for items reclassified out of accumulated other comprehensive income (loss). The guidance does not amend any existing requirements for reporting net income (loss) or other comprehensive income (loss) in the financial statements. This guidance is effective prospectively for annual reporting periods beginning after December 15, 2012, with early adoption permitted. As this new guidance is related to presentation only, the implementation of this guidance in the first quarter of fiscal year 2014 did not have a material effect on the Company’s financial condition or results of operations. In April 2014, the FASB issued guidance changing the requirements for reporting discontinued operations where a disposal of a component of an entity or group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity's operations and financial results when either classified as held for sale, or disposed of by sale or otherwise disposed. The amendment also requires enhanced disclosures about the discontinued operation and disclosure information for other significant dispositions. This guidance is effective prospectively for annual reporting periods beginning after December 15, 2014, with early adoption permitted for disposals that have not been previously reported. The implementation of this guidance is not expected to have a material effect on the Company’s financial condition or results of operations. In May 2014, the FASB issued guidance on revenue from contracts with customers. The underlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The guidance provides a five-step analysis of transactions to determine when and how revenue is recognized. Other major provisions include capitalization of certain contract costs, consideration of time value of money in the transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved, in certain circumstances. The guidance also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from an entity's contracts with customers. This guidance permits the use of either the retrospective or cumulative effect transition method and is effective for annual reporting periods beginning after December 15, 2016; early adoption is not permitted. We have not yet selected a transition method and are currently evaluating the impact of the guidance on the Company's financial condition, results of operations and related disclosures. The Company has implemented all new accounting pronouncements that are in effect and that may impact its financial statements and does not believe that there are any other new accounting pronouncements that have been issued that might have a material impact on its financial position or results of operations.

Disclosure of accounting policy for major classes of inventories, bases of stating inventories (for example, lower of cost or market), methods by which amounts are added and removed from inventory classes (for example, FIFO, LIFO, or average cost), loss recognition on impairment of inventories, and situations in which inventories are stated above cost. If inventory is carried at cost, this disclosure includes the nature of the cost elements included in inventory.

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