<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:brn="http://brninc.com/20261013"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:us-gaap="http://fasb.org/us-gaap/2025"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="brn-20261013.xsd" xlink:type="simple"/>
    <context id="c20261013to20261013">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000010048</identifier>
        </entity>
        <period>
            <startDate>2026-10-13</startDate>
            <endDate>2026-10-13</endDate>
        </period>
    </context>
    <context id="c20261013to20261013_StatementClassOfStockAxis_CommonStockPurchaseRightsMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000010048</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">brn:CommonStockPurchaseRightsMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-10-13</startDate>
            <endDate>2026-10-13</endDate>
        </period>
    </context>
    <context id="c20261013to20261013_StatementClassOfStockAxis_CommonStockMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000010048</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">us-gaap:CommonStockMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-10-13</startDate>
            <endDate>2026-10-13</endDate>
        </period>
    </context>
    <dei:AmendmentFlag
      contextRef="c20261013to20261013"
      id="Fact_726d7d2975f44ed7ab81a747d2f7b4b0">false</dei:AmendmentFlag>
    <dei:EntityCentralIndexKey
      contextRef="c20261013to20261013"
      id="Fact_2bf81da556da40a2b14a97d51113f9b2">0000010048</dei:EntityCentralIndexKey>
    <dei:DocumentType
      contextRef="c20261013to20261013"
      id="Fact_d611e4ccb7ed42928bac8b952b04d2a0">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="c20261013to20261013"
      id="Fact_487be38bbb34487ca9c02ef18214916b">2026-10-13</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="c20261013to20261013"
      id="Fact_dff23217a28d457eaebb65354133b1ea">BARNWELL INDUSTRIES INC.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="c20261013to20261013"
      id="Fact_9216b20c722b487ba31637eefcb75ca1">DE</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="c20261013to20261013"
      id="Fact_0767fa84665c4973b285141918dc3071">1-5103</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="c20261013to20261013"
      id="Fact_2261e11609db40e381348ccd28166be4">72-0496921</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="c20261013to20261013"
      id="Fact_34d1b185f1364c61a679d53bdabb8c0b">24 Greenway Plaza</dei:EntityAddressAddressLine1>
    <dei:EntityAddressAddressLine2
      contextRef="c20261013to20261013"
      id="Fact_e3b484dc03f949b4821f6c69381c1923">Suite 1800</dei:EntityAddressAddressLine2>
    <dei:EntityAddressCityOrTown
      contextRef="c20261013to20261013"
      id="Fact_978d47c359f54894ae88551be900a802">Houston</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="c20261013to20261013"
      id="Fact_eba5a2923ef5488e80cb2f8470524137">TX</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="c20261013to20261013"
      id="Fact_decdab38e1f64ca988f2c0920e12421a">77046</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="c20261013to20261013"
      id="Fact_d02b877104bd4554b6c70978d67be8e4">713</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="c20261013to20261013"
      id="Fact_34d5bd050af44c5ea5fec66942efccc5">730-7026</dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="c20261013to20261013"
      id="Fact_cb177c2f1ee54465a1bc759d53e88cdc">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="c20261013to20261013"
      id="Fact_9559a022936040b6bce1eaa7ad7c0dcc">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="c20261013to20261013"
      id="Fact_4b3f30f789ab46b8854dd62280ec073b">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="c20261013to20261013"
      id="Fact_74eef80243424198ad22294e2ca2b56d">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="c20261013to20261013_StatementClassOfStockAxis_CommonStockMember"
      id="Fact_6ae27a9a58ab4373a7f180a279da5adf">Common Stock, $0.50 Par Value</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="c20261013to20261013_StatementClassOfStockAxis_CommonStockMember"
      id="Fact_f188d2d0012f477689fd841cc2d70810">BRN</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="c20261013to20261013_StatementClassOfStockAxis_CommonStockMember"
      id="Fact_0a22c477bfd546249c3ec32b03277a02">NYSEAMER</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="c20261013to20261013_StatementClassOfStockAxis_CommonStockPurchaseRightsMember"
      id="Fact_f576221a85da40829420aecd4e586f21">Common Stock Purchase Rights</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="c20261013to20261013_StatementClassOfStockAxis_CommonStockPurchaseRightsMember"
      id="Fact_cd91a122fb6740da8f3f0732172b49e8">N/A</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="c20261013to20261013_StatementClassOfStockAxis_CommonStockPurchaseRightsMember"
      id="Fact_cf004881de33470c86be2408afb28fb3">NYSEAMER</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="c20261013to20261013"
      id="Fact_c0cad64002a94a50843ece9d4498cdfa">false</dei:EntityEmergingGrowthCompany>
</xbrl>
