COVER - USD ($)	12 Months Ended
	Sep. 30, 2022	Oct. 31, 2022	Mar. 31, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	1-06620
Entity Registrant Name	GRIFFON CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	11-1893410
Entity Address, Address Line One	712 Fifth Ave, 18th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10019
City Area Code	212
Local Phone Number	957-5000
Title of 12(b) Security	Common Stock, $0.25 par value
Trading Symbol	GFF
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,026,000,000
Entity Common Stock, Shares Outstanding		57,064,331
Documents Incorporated by Reference	Part III — (Items 10, 11, 12, 13 and 14). Registrant’s definitive proxy statement to be filed pursuant to Regulation 14A of the Securities Exchange Act of 1934.
Current Fiscal Year End Date	--09-30
Amendment Flag	false
Entity Central Index Key	0000050725
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY