LOSS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Numerator:
Net loss from continuing operations	$ (1,538)	$ (1,084)	$ (3,138)	$ (1,432)
Less: Net earnings (loss) attributable to non-controlling interests of continuing operations	0	222	(2)	224
Net loss from continuing operations attributable to Barnwell Industries, Inc.	(1,538)	(1,306)	(3,136)	(1,656)
Net earnings (loss) from discontinued operations	331	(466)	12	(780)
Net loss attributable to Barnwell Industries, Inc.	$ (1,207)	$ (1,772)	$ (3,124)	$ (2,436)
Denominator:
Basic weighted-average number of common shares outstanding	10,053,534	10,019,172	10,050,319	10,007,905
Effect of dilutive securities - common stock options and restricted stock units	0	0	0	0
Diluted weighted-average number of common shares outstanding	10,053,534	10,019,172	10,050,319	10,007,905
Basic and diluted (loss) earnings 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)	$ (0.15)	$ (0.13)	$ (0.31)	$ (0.16)
Diluted net loss per common share from continuing operations attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	(0.15)	(0.13)	(0.31)	(0.16)
Basic net earnings (loss) per common share from discontinued operations (in dollars per share)	0.03	(0.05)	0	(0.08)
Diluted net earnings (loss) per common share from discontinued operations (in dollars per share)	0.03	(0.05)	0	(0.08)
Basic net loss per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	(0.12)	(0.18)	(0.31)	(0.24)
Diluted net loss per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (0.12)	$ (0.18)	$ (0.31)	$ (0.24)
Options
Antidilutive shares excluded from the computation of diluted shares
Antidilutive shares excluded from computation of loss per share (in shares)	465,000	465,000	465,000	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)	258,699	76,336	237,475	76,336