Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Dec. 01, 2017	Mar. 31, 2017
Document and Entity Information
Entity Registrant Name	BARNWELL INDUSTRIES INC
Entity Central Index Key	0000010048
Document Type	10-K
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Public Float			$ 7,978
Entity Common Stock, Shares Outstanding		8,277,160
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY