SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation The condensed consolidated financial statements include the accounts of Barnwell Industries, Inc. and all majority-owned subsidiaries (collectively referred to herein as “Barnwell,” “we,” “our,” “us,” or the “Company”), including a 77.6%-owned land investment general partnership (Kaupulehu Developments), a 75%-owned land investment partnership (KD Kona 2013 LLLP) and an 80%-owned joint venture (Kaupulehu 2007, LLLP). All significant intercompany accounts and transactions have been eliminated. Barnwell’s investments in both unconsolidated entities in which a significant, but less than controlling, interest is held and in variable interest entities (“VIE”) in which the Company is not deemed to be the primary beneficiary are accounted for by the equity method. Unless otherwise indicated, all references to “dollars” in this Form 10-Q are to U.S. dollars. Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements and notes have been prepared by Barnwell in accordance with the rules and regulations of the United States (“U.S.”) Securities and Exchange Commission. Accordingly, certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made are adequate to make the information not misleading. These condensed consolidated financial statements and notes should be read in conjunction with the consolidated financial statements and notes thereto included in Barnwell’s September 30, 2017 Annual Report on Form 10-K. The Condensed Consolidated Balance Sheet as of September 30, 2017 has been derived from audited consolidated financial statements. In the opinion of management, all adjustments (which include only normal recurring adjustments) necessary to present fairly the financial position at March 31, 2018, results of operations and comprehensive income (loss) for the three and six months ended March 31, 2018 and 2017, and equity and cash flows for the six months ended March 31, 2018 and 2017, have been made. The results of operations for the period ended March 31, 2018 are not necessarily indicative of the operating results for the full year. Use of Estimates The preparation of the financial statements in conformity with U.S. GAAP requires management of Barnwell to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ significantly from those estimates. Significant Accounting Policies There have been no changes to Barnwell’s significant accounting policies as described in the Notes to Consolidated Financial Statements included in Item 8 of the Company’s most recently filed Annual Report on Form 10-K. Recently Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-07, “Simplifying the Transition to the Equity Method of Accounting,” which eliminates the requirement that when an investment subsequently qualifies for use of the equity method as a result of an increase in level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. This ASU requires that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and to adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. In addition, the ASU requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The Company adopted the provisions of this ASU effective October 1, 2017. The adoption of this update did not have an impact on Barnwell’s consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting,” which includes provisions intended to simplify various aspects related to how share-based payments are accounted for and presented in the financial statements. The Company adopted the provisions of this ASU effective October 1, 2017. The adoption of this update did not have an impact on Barnwell’s consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-17, “Interests Held through Related Parties That Are under Common Control,” which modifies existing guidance with respect to how a decision maker that holds an indirect interest in a VIE through a common control party determines whether it is the primary beneficiary of the VIE as part of the analysis of whether the VIE would need to be consolidated. Under this ASU, a decision maker would need to consider only its proportionate indirect interest in the VIE held through a common control party. The Company adopted the provisions of this ASU effective October 1, 2017. The adoption of this update did not have an impact on Barnwell’s consolidated financial statements.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Principles of Consolidation

The condensed consolidated financial statements include the accounts of Barnwell Industries, Inc. and all majority-owned subsidiaries (collectively referred to herein as “Barnwell,” “we,” “our,” “us,” or the “Company”), including a 77.6%-owned land investment general partnership (Kaupulehu Developments), a 75%-owned land investment partnership (KD Kona 2013 LLLP) and an 80%-owned joint venture (Kaupulehu 2007, LLLP). All significant intercompany accounts and transactions have been eliminated.

Barnwell’s investments in both unconsolidated entities in which a significant, but less than controlling, interest is held and in variable interest entities (“VIE”) in which the Company is not deemed to be the primary beneficiary are accounted for by the equity method.

Unless otherwise indicated, all references to “dollars” in this Form 10-Q are to U.S. dollars.

Unaudited Interim Financial Information

The accompanying unaudited condensed consolidated financial statements and notes have been prepared by Barnwell in accordance with the rules and regulations of the United States (“U.S.”) Securities and Exchange Commission. Accordingly, certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made are adequate to make the information not misleading. These condensed consolidated financial statements and notes should be read in conjunction with the consolidated financial statements and notes thereto included in Barnwell’s September 30, 2017 Annual Report on Form 10-K. The Condensed Consolidated Balance Sheet as of September 30, 2017 has been derived from audited consolidated financial statements.

In the opinion of management, all adjustments (which include only normal recurring adjustments) necessary to present fairly the financial position at March 31, 2018, results of operations and comprehensive income (loss) for the three and six months ended March 31, 2018 and 2017, and equity and cash flows for the six months ended March 31, 2018 and 2017, have been made. The results of operations for the period ended March 31, 2018 are not necessarily indicative of the operating results for the full year.

Use of Estimates

The preparation of the financial statements in conformity with U.S. GAAP requires management of Barnwell to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ significantly from those estimates.

Significant Accounting Policies

There have been no changes to Barnwell’s significant accounting policies as described in the Notes to Consolidated Financial Statements included in Item 8 of the Company’s most recently filed Annual Report on Form 10-K.

Recently Adopted Accounting Pronouncements

In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-07, “Simplifying the Transition to the Equity Method of Accounting,” which eliminates the requirement that when an investment subsequently qualifies for use of the equity method as a result of an increase in level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. This ASU requires that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and to adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. In addition, the ASU requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The Company adopted the provisions of this ASU effective October 1, 2017. The adoption of this update did not have an impact on Barnwell’s consolidated financial statements.

In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting,” which includes provisions intended to simplify various aspects related to how share-based payments are accounted for and presented in the financial statements. The Company adopted the provisions of this ASU effective October 1, 2017. The adoption of this update did not have an impact on Barnwell’s consolidated financial statements.

In October 2016, the FASB issued ASU No. 2016-17, “Interests Held through Related Parties That Are under Common Control,” which modifies existing guidance with respect to how a decision maker that holds an indirect interest in a VIE through a common control party determines whether it is the primary beneficiary of the VIE as part of the analysis of whether the VIE would need to be consolidated. Under this ASU, a decision maker would need to consider only its proportionate indirect interest in the VIE held through a common control party. The Company adopted the provisions of this ASU effective October 1, 2017. The adoption of this update did not have an impact on Barnwell’s consolidated financial statements.