CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (1,518)	$ (2,151)	$ (1,937)	$ (6,724)
Other comprehensive (loss) income:
Foreign currency translation adjustments, net of taxes of $0	84	130	89	(283)
Retirement plans:
Amortization of accumulated other comprehensive loss into net periodic benefit cost, net of taxes of $0	20	16	80	33
Net actuarial gains arising during the period, net of taxes of $0	0	0	880	0
Curtailment gain, net of taxes of $0	0	0	1,699	0
Total other comprehensive (loss) income	104	146	2,748	(250)
Total comprehensive (loss) income	(1,414)	(2,005)	811	(6,974)
Less: Comprehensive (loss) income attributable to non-controlling interests	(4)	(26)	(9)	1
Comprehensive (loss) income attributable to Barnwell Industries, Inc.	$ (1,410)	$ (1,979)	$ 820	$ (6,975)