COMMITMENTS AND CONTINGENCIES	12 Months Ended
COMMITMENTS AND CONTINGENCIES	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Incentive compensation plan In fiscal 2020, Barnwell established an incentive compensation plan to compensate all Canadian oil and natural gas segment personnel and an incentive compensation plan to compensate Canadian executive officers. The value of the plans are directly related to our oil and natural gas segment's free cash flows and the divestiture of oil and natural gas assets. As of September 30, 2020, Barnwell has accrued approximately $23,000 in bonus compensation under these plans and the amount is reported in “Accrued compensation” on the Consolidated Balance Sheet at September 30, 2020. Environmental Matters Because of the inherent uncertainties associated with environmental assessment and remediation activities, future expenses to remediate sites identified in the future, if any, could be incurred. Barnwell's management is not currently aware of any significant environmental contingent liabilities requiring disclosure or accrual. Legal and Regulatory Matters Barnwell is routinely involved in disputes with third parties that occasionally require litigation. In addition, Barnwell is required to maintain compliance with all current governmental controls and regulations in the ordinary course of business. Barnwell’s management is not aware of any claims or litigation involving Barnwell that are likely to have a material adverse effect on its results of operations, financial position or liquidity. In the year ended September 30, 2019, two of the water wells drilled by the contract drilling segment for one customer were determined to not meet the contract specifications for plumbness. Subsequently, in the quarter ended March 31, 2020, the Company executed a separate five-year warranty agreement with the customer for one of the wells that did not meet plumbness. Under the terms of the agreement, if the lack of plumbness is determined to be the cause of a pump failure within the warranty period, the Company would be obligated to replace the pump at no cost to the customer. If the Company is unable to replace the pump using industry-standard methods, or if there are two or more pump failures attributable to lack of plumbness within the five-year warranty period, the Company would be obligated to drill a new well at no cost to the customer. Negotiations with the customer are currently ongoing for the other well that the customer claims did not meet plumbness despite the fact that the independent consulting engineer for the job concluded that the most recent plumbness test, completed after the well was cased with casing cemented into place as per the contract, showed that the well meets the plumbness specifications of the contract. Management believes the degrees of deviation for both wells are not impactful to the performance of the submersible pumps that will be installed in those wells. Accordingly, no accruals have been recorded as of September 30, 2020 as there is no probable or estimable contingent liability. On July 28, 2020, the Staff of the Commission circulated a draft of a proposed recommendation to the Commission under which the Company, the water utility, the water utility's independent hydrologist firm and the owner of the land on which the two aforementioned water wells were drilled would be assessed penalty fines because each of the wells were calculated to have been drilled beyond the depth permitted by the permit. The wells were drilled to a depth to penetrate certain layers of impermeable rock necessary to access the aquifer at the instructions and on the advice of the hydrologist hired by the owner of the well. The Company’s share of the proposed penalties and fines were originally calculated to approximately $1,200,000. Subsequently, the Staff of the Commission acknowledged that one well had not been drilled to a depth beyond its permitted depth and the fines on that well were eliminated. Additionally, the fines applicable to the depth of the second well were recalculated and reduced to approximately $300,000 as to the Company. The Commission and the aforementioned four parties have worked on a possible proposed alternative settlement in lieu of the penalties and fines whereby the named parties would be responsible for providing the Commission with assistance to monitor the aquifer, at no cost to the Commission, to aid in the Commission’s efforts to monitor water quality in the subject area. The Company and the other three parties are currently evaluating proposals that it believes would likely satisfy the Commission's request under the proposed alternative settlement but it is currently uncertain as to whether or not they will be acceptable to the Commission. Additionally, it is uncertain as to how the cost of the alternative settlement would be allocated to the named parties of the subject violations. Accordingly, the Company recorded a contingent liability of approximately $300,000 at September 30, 2020. Other Matters Barnwell is obligated to pay Nearco Enterprises Ltd. 10.4%, net of non-controlling interests' share, of Kaupulehu Developments’ gross receipts from real estate transactions. The fees represent compensation for promotion and marketing of Kaupulehu Developments’ property and were determined based on the estimated fair value of such services. These fees are included in general and administrative expenses. Barnwell is obligated to pay its external real estate legal counsel 1.2%, net of non-controlling interests' share, of all Increment II payments received by Kaupulehu Developments for services provided by its external real estate legal counsel in the negotiation and closing of the Increment II transaction. These fees are included in general and administrative expenses. Effective March 2019, Barnwell is now also obligated to pay an amount equal to 0.72% and 0.20% of the cumulative net profits of KD II to KD Development, LLC and a pool of various individuals, respectively, all of whom are partners of KKM and are unrelated to Barnwell, in compensation for the agreement of these parties to admit the new development partner for Increment II. Such compensation will be reflected as the obligation becomes probable and the amount of the obligation can be reasonably estimated.