CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (794)	$ (1,518)	$ (51)	$ (1,937)
Other comprehensive (loss) income:
Foreign currency translation adjustments, net of taxes of $0	(85)	84	(319)	89
Retirement plans:
Amortization of accumulated other comprehensive loss into net periodic benefit cost, net of taxes of $0	33	20	66	80
Net actuarial gains arising during the period, net of taxes of $0	0	0	0	880
Curtailment gain, net of taxes of $0	0	0	0	1,699
Total other comprehensive (loss) income	(52)	104	(253)	2,748
Total comprehensive (loss) income	(846)	(1,414)	(304)	811
Less: Comprehensive (income) loss attributable to non-controlling interests	(62)	4	(221)	9
Comprehensive (loss) income attributable to Barnwell Industries, Inc.	$ (908)	$ (1,410)	$ (525)	$ 820