GOING CONCERN	6 Months Ended
GOING CONCERN	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
GOING CONCERN	GOING CONCERN The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business for the twelve-month period following the date of issuance of these condensed consolidated financial statements. Our ability to sustain our business in the future will depend on sufficient oil and natural gas operating cash flows, which are highly sensitive to volatile oil and natural gas prices, sufficient contract drilling operating cash flows, which are subject to large changes in demand, and sufficient future land investment segment proceeds and distributions from the Kukio Resort Land Development Partnerships, the timing of which are both highly uncertain and not within Barnwell’s control. A sufficient level of such cash inflows are necessary to fund discretionary oil and natural gas capital expenditures, which must be economically successful to provide sufficient returns, as well as fund our non-discretionary outflows such as oil and natural gas asset retirement obligations and ongoing operating and general and administrative expenses. In addition, as discussed in the "Asset Retirement Obligation" section of "Liquidity and Capital Resources," a significant amount of funds will be required to be put on deposit with Canadian regulatory authorities to fund abandonments at the Company's oil and natural gas properties in the Manyberries area. The Company listed its corporate office on the 29th floor of a commercial office building in downtown Honolulu, Hawaii for sale to generate liquidity in order to help mitigate the substantial doubt about our ability to continue as a going concern. The corporate office is currently under a purchase and sales contract with a buyer with a tentative closing to occur prior to September 30, 2021. While the Company believes the likelihood of the sale occurring as per the terms of the contract is more likely than not, the Company’s ability to successfully consummate the sale cannot be assured. On March 16, 2021, the Company initiated an at-the-market offering program (“ATM”) pursuant to which the Company may offer and sell, from time to time, shares of its common stock under price and volume guidelines set by the Company's Board of Directors and the terms and conditions described in the Registration Statement. As of the filing date of this Quarterly Report, no shares have been sold under the ATM, and there is no assurance that a sufficient level of funds can be raised by the ATM. In April 2021, the Company re-initiated the marketing of its non-core oil and natural gas properties in the Spirit River, Wood River, Medicine River, Kaybob, Bonanza, Balsam and Thornbury areas for sale. These properties were previously marketed for sale in January 2020, before the COVID-19 lockdowns began, but the Company did not receive any suitable offers, in part due to the impact of COVID-19 on oil and gas markets. There is no assurance that the sale of these properties will occur. We have experienced a trend of losses and negative operating cash flows in three of the last four years. While potential sources of liquidity may come from the aforementioned initiatives, due to the continuing uncertainties regarding the impacts of the COVID-19 pandemic on our business and the sufficiency of our cash balances and future cash inflows as described above, there is substantial doubt about our ability to meet our estimated cash outflows or continue as a going concern for one year from the date of the filing of this report. These financial statements do not include any adjustments that might result from the outcome of these uncertainties.