LOSS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Numerator:
Net loss from continuing operations	$ (7,123)	$ (3,871)
Less: Net (loss) earnings attributable to non-controlling interests	(8)	234
Net loss from continuing operations attributable to Barnwell Industries, Inc.	(7,115)	(4,105)
Net earnings (loss) from discontinued operations	12	(1,460)
Net loss attributable to Barnwell Industries, Inc.	$ (7,103)	$ (5,565)
Denominator:
Basic weighted-average number of common shares outstanding	10,056,479	10,017,997
Effect of dilutive securities - common stock options and restricted stock units	0	0
Diluted weighted-average number of common shares outstanding	10,056,479	10,017,997
Basic and diluted loss per common share attributable to Barnwell Industries, Inc. stockholders:
Basic net loss per common share from continuing operations attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (0.71)	$ (0.41)
Diluted net loss per common share from continuing operations attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	(0.71)	(0.41)
Basic net loss per common share from discontinued operations (in dollars per share)	0	(0.15)
Diluted net loss per common share from discontinued operations (in dollars per share)	0	(0.15)
Basic net loss per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	(0.71)	(0.56)
Diluted net loss per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (0.71)	$ (0.56)
Options
Antidilutive shares excluded from the computation of diluted shares
Antidilutive shares excluded from computation of loss per share (in shares)	454,452	465,000
Restricted Stock Units (RSUs)
Antidilutive shares excluded from the computation of diluted shares
Antidilutive shares excluded from computation of loss per share (in shares)	218,300	98,795