<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>219</ContextCount>
  <ElementCount>357</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>72</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>19</UnitCount>
  <MyReports>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Document - Audit Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AuditInformation</Role>
      <ShortName>Audit Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952151 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952153 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - CONSOLIDATED STATEMENTS OF EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CONSOLIDATEDSTATEMENTSOFEQUITY</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952156 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952157 - Statement - CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CONSOLIDATEDSTATEMENTSOFEQUITYParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - BUSINESS AND BASIS OF PRESENTATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/BUSINESSANDBASISOFPRESENTATION</Role>
      <ShortName>BUSINESS AND BASIS OF PRESENTATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - ASSET RETIREMENT OBLIGATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/ASSETRETIREMENTOBLIGATIONS</Role>
      <ShortName>ASSET RETIREMENT OBLIGATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - OIL AND NATURAL GAS PROPERTIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/OILANDNATURALGASPROPERTIES</Role>
      <ShortName>OIL AND NATURAL GAS PROPERTIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTS</Role>
      <ShortName>COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - FAIR VALUE MEASUREMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FAIRVALUEMEASUREMENTS</Role>
      <ShortName>FAIR VALUE MEASUREMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - SIGNIFICANT OPERATORS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SIGNIFICANTOPERATORS</Role>
      <ShortName>SIGNIFICANT OPERATORS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - CREDIT FACILITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CREDITFACILITY</Role>
      <ShortName>CREDIT FACILITY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - INCENTIVE COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATION</Role>
      <ShortName>INCENTIVE COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - EMPLOYEE BENEFIT PLANS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EMPLOYEEBENEFITPLANS</Role>
      <ShortName>EMPLOYEE BENEFIT PLANS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMITMENTSANDCONTINGENCIES</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - PREFERRED UNITS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/PREFERREDUNITS</Role>
      <ShortName>PREFERRED UNITS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - EARNINGS PER UNIT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EARNINGSPERUNIT</Role>
      <ShortName>EARNINGS PER UNIT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - COMMON UNITS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMONUNITS</Role>
      <ShortName>COMMON UNITS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - SUBSEQUENT EVENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUBSEQUENTEVENTS</Role>
      <ShortName>SUBSEQUENT EVENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITED</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995447 - Disclosure - Insider Trading Policies and Procedures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc</Role>
      <ShortName>Insider Trading Policies and Procedures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure</Role>
      <ShortName>Cybersecurity Risk Management and Strategy Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - ASSET RETIREMENT OBLIGATIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/ASSETRETIREMENTOBLIGATIONSTables</Role>
      <ShortName>ASSET RETIREMENT OBLIGATIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/ASSETRETIREMENTOBLIGATIONS</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTSTables</Role>
      <ShortName>COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTS</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - FAIR VALUE MEASUREMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FAIRVALUEMEASUREMENTSTables</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/FAIRVALUEMEASUREMENTS</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - INCENTIVE COMPENSATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATIONTables</Role>
      <ShortName>INCENTIVE COMPENSATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATION</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - EARNINGS PER UNIT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EARNINGSPERUNITTables</Role>
      <ShortName>EARNINGS PER UNIT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/EARNINGSPERUNIT</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITEDTables</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITED</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - BUSINESS AND BASIS OF PRESENTATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/BUSINESSANDBASISOFPRESENTATIONDetails</Role>
      <ShortName>BUSINESS AND BASIS OF PRESENTATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/BUSINESSANDBASISOFPRESENTATION</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Accrued Revenue and Accounts Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleofAccruedRevenueandAccountsReceivableDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Accrued Revenue and Accounts Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Accrued Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleofAccruedLiabilitiesDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Accrued Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - ASSET RETIREMENT OBLIGATIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/ASSETRETIREMENTOBLIGATIONSDetails</Role>
      <ShortName>ASSET RETIREMENT OBLIGATIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/ASSETRETIREMENTOBLIGATIONSTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - OIL AND NATURAL GAS PROPERTIES - Acquisitions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/OILANDNATURALGASPROPERTIESAcquisitionsDetails</Role>
      <ShortName>OIL AND NATURAL GAS PROPERTIES - Acquisitions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - OIL AND NATURAL GAS PROPERTIES - Asset Exchange (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/OILANDNATURALGASPROPERTIESAssetExchangeDetails</Role>
      <ShortName>OIL AND NATURAL GAS PROPERTIES - Asset Exchange (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - OIL AND NATURAL GAS PROPERTIES - Farmout Agreements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/OILANDNATURALGASPROPERTIESFarmoutAgreementsDetails</Role>
      <ShortName>OIL AND NATURAL GAS PROPERTIES - Farmout Agreements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - OIL AND NATURAL GAS PROPERTIES - Impairment of Oil and Natural Gas Properties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/OILANDNATURALGASPROPERTIESImpairmentofOilandNaturalGasPropertiesDetails</Role>
      <ShortName>OIL AND NATURAL GAS PROPERTIES - Impairment of Oil and Natural Gas Properties (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTSNarrativeDetails</Role>
      <ShortName>COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Fair Value and Classification of Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTSScheduleofFairValueandClassificationofDerivativeInstrumentsDetails</Role>
      <ShortName>COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Fair Value and Classification of Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Changes in Fair Value of Company's Commodity Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTSScheduleofChangesinFairValueofCompanysCommodityDerivativeInstrumentsDetails</Role>
      <ShortName>COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Changes in Fair Value of Company's Commodity Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Open Derivative Contracts for Oil and Natural Gas (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMODITYDERIVATIVEFINANCIALINSTRUMENTSScheduleofOpenDerivativeContractsforOilandNaturalGasDetails</Role>
      <ShortName>COMMODITY DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Open Derivative Contracts for Oil and Natural Gas (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - FAIR VALUE MEASUREMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FAIRVALUEMEASUREMENTSDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/FAIRVALUEMEASUREMENTSTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - SIGNIFICANT OPERATORS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SIGNIFICANTOPERATORSDetails</Role>
      <ShortName>SIGNIFICANT OPERATORS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/SIGNIFICANTOPERATORS</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - CREDIT FACILITY (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CREDITFACILITYDetails</Role>
      <ShortName>CREDIT FACILITY (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/CREDITFACILITY</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - INCENTIVE COMPENSATION - Schedule of Information about Restricted Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATIONScheduleofInformationaboutRestrictedUnitsDetails</Role>
      <ShortName>INCENTIVE COMPENSATION - Schedule of Information about Restricted Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - INCENTIVE COMPENSATION - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATIONNarrativeDetails</Role>
      <ShortName>INCENTIVE COMPENSATION - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - INCENTIVE COMPENSATION - Schedule of Information about Performance Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATIONScheduleofInformationaboutPerformanceUnitsDetails</Role>
      <ShortName>INCENTIVE COMPENSATION - Schedule of Information about Performance Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - INCENTIVE COMPENSATION - Schedule of Incentive Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/INCENTIVECOMPENSATIONScheduleofIncentiveCompensationExpenseDetails</Role>
      <ShortName>INCENTIVE COMPENSATION - Schedule of Incentive Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - EMPLOYEE BENEFIT PLANS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EMPLOYEEBENEFITPLANSDetails</Role>
      <ShortName>EMPLOYEE BENEFIT PLANS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/EMPLOYEEBENEFITPLANS</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMITMENTSANDCONTINGENCIESDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/COMMITMENTSANDCONTINGENCIES</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - PREFERRED UNITS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/PREFERREDUNITSDetails</Role>
      <ShortName>PREFERRED UNITS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/PREFERREDUNITS</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - EARNINGS PER UNIT - Schedule of Computation of Basic and Diluted Earnings per Unit (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EARNINGSPERUNITScheduleofComputationofBasicandDilutedEarningsperUnitDetails</Role>
      <ShortName>EARNINGS PER UNIT - Schedule of Computation of Basic and Diluted Earnings per Unit (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - EARNINGS PER UNIT - Schedule of Potentially Dilutive Securities Excluded from Computation of Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EARNINGSPERUNITScheduleofPotentiallyDilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails</Role>
      <ShortName>EARNINGS PER UNIT - Schedule of Potentially Dilutive Securities Excluded from Computation of Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9955544 - Disclosure - COMMON UNITS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/COMMONUNITSDetails</Role>
      <ShortName>COMMON UNITS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/COMMONUNITS</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9955545 - Disclosure - SUBSEQUENT EVENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUBSEQUENTEVENTSDetails</Role>
      <ShortName>SUBSEQUENT EVENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/SUBSEQUENTEVENTS</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9955546 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Costs Incurred in Oil and Natural Gas Property Acquisitions, Exploration, and Development Activities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITEDScheduleofCostsIncurredinOilandNaturalGasPropertyAcquisitionsExplorationandDevelopmentActivitiesDetails</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Costs Incurred in Oil and Natural Gas Property Acquisitions, Exploration, and Development Activities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9955547 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Oil and Natural Gas Capitalized Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITEDScheduleofOilandNaturalGasCapitalizedCostsDetails</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Oil and Natural Gas Capitalized Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9955548 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Estimated Net Quantities of Partnership Proved, Proved Developed and Proved Undeveloped Oil and Natural Gas Reserve (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITEDScheduleofEstimatedNetQuantitiesofPartnershipProvedProvedDevelopedandProvedUndevelopedOilandNaturalGasReserveDetails</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Estimated Net Quantities of Partnership Proved, Proved Developed and Proved Undeveloped Oil and Natural Gas Reserve (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9955549 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Standardized Measure of Discounted Future Net Cash Flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITEDScheduleofStandardizedMeasureofDiscountedFutureNetCashFlowsDetails</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Standardized Measure of Discounted Future Net Cash Flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="bsm-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9955550 - Disclosure - SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Changes in Standardized Measure of Discounted Future Net Cash Flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SUPPLEMENTALOILANDNATURALGASDISCLOSURESUNAUDITEDScheduleofChangesinStandardizedMeasureofDiscountedFutureNetCashFlowsDetails</Role>
      <ShortName>SUPPLEMENTAL OIL AND NATURAL GAS DISCLOSURES???UNAUDITED - Schedule of Changes in Standardized Measure of Discounted Future Net Cash Flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-K" isDefinitelyFs="true" isUsgaap="true" original="bsm-20251231.htm">bsm-20251231.htm</File>
    <File>bsm-20251231.xsd</File>
    <File>bsm-20251231_cal.xml</File>
    <File>bsm-20251231_def.xml</File>
    <File>bsm-20251231_lab.xml</File>
    <File>bsm-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>bsm-20251231_g1.jpg</File>
    <File>bsm-20251231_g2.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="140">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="706">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="39">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="12">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
