Document and Entity Information - shares	3 Months Ended
	Dec. 31, 2019	Feb. 07, 2020
Document and Entity Information
Entity Registrant Name	BARNWELL INDUSTRIES INC
Entity Central Index Key	0000010048
Document Type	10-Q
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		8,277,160
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1