(LOSS) EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Net Earnings (Loss) (Numerator)
Basic	$ (12,414)	$ (1,770)
Diluted	$ (12,414)	$ (1,770)
Shares (Denominator)
Basic (in shares)	8,277,160	8,277,160
Effect of dilutive securities-common stock options (in shares)	0	0
Diluted (in shares)	8,277,160	8,277,160
Per-Share Amount
Basic net loss per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (1.50)	$ (0.21)
Diluted net loss per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (1.50)	$ (0.21)
Options
Antidilutive shares of common stock excluded from the computation of diluted shares
Antidilutive shares excluded from computation of earnings (loss) per share (in shares)	318,750	318,750