OIL AND NATURAL GAS PROPERTIES (Details) - USD ($)	1 Months Ended	12 Months Ended		24 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 12, 2016	Aug. 27, 2015	Nov. 13, 2014
Oil and natural gas properties
Liabilities associated with properties sold		$ 0	$ 2,013,000
Revenues		13,287,000	17,533,000
Net earnings (loss)		(2,864,000)	1,769,000
Net earnings (loss) attributable to Barnwell Industries, Inc. stockholders		$ (3,615,000)	$ 1,263,000
Basic net earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)		$ (0.44)	$ 0.15
Oil and natural gas properties | Progress November 2014 [Member]
Oil and natural gas properties
Property and equipment							$ 751,000
Asset retirement obligation							(225,000)
Net identifiable assets acquired							$ 526,000
Oil and natural gas properties | Progress August 2015 [Member]
Oil and natural gas properties
Property and equipment						$ 397,000
Asset retirement obligation						(91,000)
Net identifiable assets acquired						$ 306,000
Oil and natural gas properties | Wood River Sept 2016 [Member]
Oil and natural gas properties
Property and equipment					$ 813,000
Asset retirement obligation					(44,000)
Net identifiable assets acquired					$ 769,000
Oil and natural gas properties | Dunvegan and Belloy areas of Alberta
Oil and natural gas properties
Divestiture of businesses, sale price	$ 21,875,000
Proceeds from divestiture of businesses	$ 14,162,000	$ 493,000
Percent difference in capitalized costs divided by proved reserves	220.00%
Gain (loss) recognized from property sales		$ 472,000	$ 6,217,000
Liabilities associated with properties sold			2,013,000
Revenues			17,533,000
Net earnings (loss)			1,769,000
Net earnings (loss) attributable to Barnwell Industries, Inc. stockholders			$ 1,263,000
Basic net earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)			$ 0.15
Cumulative gain on sale of oil and gas property				$ 6,689,000
Oil and natural gas properties | Dunvegan and Belloy areas of Alberta | Pro Forma
Oil and natural gas properties
Revenues			$ 13,235,000
Net earnings (loss)			(761,000)
Net earnings (loss) attributable to Barnwell Industries, Inc. stockholders			$ (1,267,000)
Basic net earnings (loss) per common share attributable to Barnwell Industries, Inc. stockholders (in dollars per share)			$ (0.15)
Oil and natural gas properties | Dunvegan and Belloy areas of Alberta | Working Interest Owner
Oil and natural gas properties
Proceeds from divestiture of businesses	$ 7,247,000