EARNINGS (LOSS) PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Net Earnings (Loss) (Numerator)
Basic	$ 1,171	$ (3,615)
Diluted	$ 1,171	$ (3,615)
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 earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ 0.14	$ (0.44)
Diluted net earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ 0.14	$ (0.44)
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)	593,750	621,250

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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