CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Revenues	$ 9,368,000	$ 13,030,000
Costs and expenses:
Oil and natural gas operating	2,633,000	3,028,000
Contract drilling operating	3,650,000	3,231,000
General and administrative	6,262,000	6,976,000
Depletion, depreciation, and amortization	1,111,000	1,203,000
Impairment of assets	202,000	155,000
Gain on sales of assets	(2,255,000)	(527,000)
Interest expense	7,000	6,000
Total costs and expenses	11,610,000	14,072,000
Loss before equity in income of affiliates and income taxes	(2,242,000)	(1,042,000)
Equity in income of affiliates	223,000	2,276,000
(Loss) earnings before income taxes	(2,019,000)	1,234,000
Income tax benefit	(601,000)	(1,080,000)
Net (loss) earnings	(1,418,000)	2,314,000
Less: Net earnings attributable to non-controlling interests	352,000	1,143,000
Net (loss) earnings attributable to Barnwell Industries, Inc. stockholders	$ (1,770,000)	$ 1,171,000
Basic net earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (0.21)	$ 0.14
Diluted net earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)	$ (0.21)	$ 0.14
Weighted-average number of common shares outstanding:
Basic (in shares)	8,277,160	8,277,160
Diluted (in shares)	8,277,160	8,277,160
Oil and natural gas
Revenues:
Revenues	$ 3,706,000	$ 4,383,000
Contract drilling
Revenues:
Revenues	3,769,000	3,938,000
Sale of interest in leasehold land
Revenues:
Revenues	1,645,000	4,503,000
Gas processing and other
Revenues:
Revenues	$ 248,000	$ 206,000