Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2020	Jun. 19, 2020
Document and Entity Information
Entity Registrant Name	BARNWELL INDUSTRIES INC
Entity Central Index Key	0000010048
Document Type	10-Q
Document Period End Date	Mar. 31, 2020
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		8,277,160