Document And Entity Information	3 Months Ended
	Dec. 31, 2015 shares
Document and Entity Information [Abstract]
Entity Registrant Name	GRIFFON CORP
Document Type	10-Q
Current Fiscal Year End Date	--09-30
Entity Common Stock, Shares Outstanding	48,083,859
Amendment Flag	false
Entity Central Index Key	0000050725
Entity Current Reporting Status	Yes
Entity Voluntary FIlers	No
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q1