OTHER INCOME (EXPENSE)	3 Months Ended
Dec. 31, 2019
Other Income and Expenses [Abstract]
OTHER INCOME (EXPENSE)	OTHER INCOME (EXPENSE) For the quarters ended December 31, 2019 and 2018, Other income (expense) includes $(376) and $502, respectively, of net currency exchange gains (losses) in connection with the translation of receivables and payables denominated in currencies other than the functional currencies of Griffon and its subsidiaries, net periodic benefit plan income of $389 and $787, respectively, as well as $81 and $(77), respectively, of net investment (loss) income. During the quarter ended December 31, 2019, Other income (expense) also includes a one-time contract award of $700.

The entire disclosure for other income or other expense items (both operating and nonoperating). Sources of nonoperating income or nonoperating expense that may be disclosed, include amounts earned from dividends, interest on securities, profits (losses) on securities, net and miscellaneous other income or income deductions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
-URI http://asc.fasb.org/topic&trid=2122503

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 610
-URI http://asc.fasb.org/topic&trid=49130413

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