<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.7.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>183</ContextCount>
  <ElementCount>225</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>71</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>14</UnitCount>
  <MyReports>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0002000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - 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>2</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001501 - 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>3</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - 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>4</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004000 - Statement - CONSOLIDATED STATEMENT OF EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/ConsolidatedStatementOfEquity</Role>
      <ShortName>CONSOLIDATED STATEMENT OF EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005000 - 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>6</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2101100 - 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>7</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2102100 - 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>8</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2103100 - 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>9</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - Acquisitions and Dispositions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AcquisitionsAndDispositions</Role>
      <ShortName>Acquisitions and Dispositions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Derivatives and Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstruments</Role>
      <ShortName>Derivatives and Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - Fair Value Measurement</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FairValueMeasurement</Role>
      <ShortName>Fair Value Measurement</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Credit Facility</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CreditFacility</Role>
      <ShortName>Credit Facility</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2108100 - 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>14</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - Incentive Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/IncentiveCompensation</Role>
      <ShortName>Incentive Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Redeemable Preferred Units</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/RedeemablePreferredUnits</Role>
      <ShortName>Redeemable Preferred Units</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2111100 - 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>17</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - AT-THE-MARKET OFFERING PROGRAM</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AtTheMarketOfferingProgram</Role>
      <ShortName>AT-THE-MARKET OFFERING PROGRAM</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2202201 - 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>
      <ParentRole>http://www.blackstoneminerals.com/role/SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2303301 - 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>21</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - Acquisitions and Dispositions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AcquisitionsAndDispositionsTables</Role>
      <ShortName>Acquisitions and Dispositions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/AcquisitionsAndDispositions</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - Derivatives and Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstrumentsTables</Role>
      <ShortName>Derivatives and Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstruments</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - Fair Value Measurement (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FairValueMeasurementTables</Role>
      <ShortName>Fair Value Measurement (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/FairValueMeasurement</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2309301 - 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>25</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2311301 - 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>26</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2401401 - Disclosure - Business and Basis of Presentation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/BusinessAndBasisOfPresentationAdditionalInformationDetails</Role>
      <ShortName>Business and Basis of Presentation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - Asset Retirement Obligations - Schedule of Change in Asset Retirement Obligation Liability (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AssetRetirementObligationsScheduleOfChangeInAssetRetirementObligationLiabilityDetails</Role>
      <ShortName>Asset Retirement Obligations - Schedule of Change in Asset Retirement Obligation Liability (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - Acquisitions and Dispositions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AcquisitionsAndDispositionsAdditionalInformationDetails</Role>
      <ShortName>Acquisitions and Dispositions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2404403 - Disclosure - Acquisitions and Dispositions - Schedule of Fair Values of the Properties Acquired (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AcquisitionsAndDispositionsScheduleOfFairValuesOfPropertiesAcquiredDetails</Role>
      <ShortName>Acquisitions and Dispositions - Schedule of Fair Values of the Properties Acquired (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Derivatives and Financial Instruments - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstrumentsAdditionalInformationDetails</Role>
      <ShortName>Derivatives and Financial Instruments - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2405403 - Disclosure - Derivatives and Financial Instruments - Summary of Fair Value and Classification of Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstrumentsSummaryOfFairValueAndClassificationOfDerivativeInstrumentsDetails</Role>
      <ShortName>Derivatives and Financial Instruments - Summary of Fair Value and Classification of Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2405404 - Disclosure - Derivatives and Financial Instruments - Changes in Fair Value of Company's Commodity Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstrumentsChangesInFairValueOfCompanysCommodityDerivativeInstrumentsDetails</Role>
      <ShortName>Derivatives and Financial Instruments - Changes in Fair Value of Company's Commodity Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2405405 - Disclosure - Derivatives and Financial Instruments - Summary of Open Derivative Contracts for Oil and Natural Gas (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/DerivativesAndFinancialInstrumentsSummaryOfOpenDerivativeContractsForOilAndNaturalGasDetails</Role>
      <ShortName>Derivatives and Financial Instruments - Summary of Open Derivative Contracts for Oil and Natural Gas (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - Fair Value Measurement - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FairValueMeasurementAdditionalInformationDetails</Role>
      <ShortName>Fair Value Measurement - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2406403 - Disclosure - Fair Value Measurement - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FairValueMeasurementScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails</Role>
      <ShortName>Fair Value Measurement - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2406404 - Disclosure - Fair Value Measurement - Schedule of Assets Measured at Fair Value on a Nonrecurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/FairValueMeasurementScheduleOfAssetsMeasuredAtFairValueOnNonrecurringBasisDetails</Role>
      <ShortName>Fair Value Measurement - Schedule of Assets Measured at Fair Value on a Nonrecurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2407401 - Disclosure - Credit Facility - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CreditFacilityAdditionalInformationDetails</Role>
      <ShortName>Credit Facility - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2408401 - Disclosure - Commitments and Contingencies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/CommitmentsAndContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - Incentive Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/IncentiveCompensationAdditionalInformationDetails</Role>
      <ShortName>Incentive Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2409403 - Disclosure - Incentive Compensation - Summary of Incentive Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/IncentiveCompensationSummaryOfIncentiveCompensationExpenseDetails</Role>
      <ShortName>Incentive Compensation - Summary of Incentive Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2410401 - Disclosure - Redeemable Preferred Units - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/RedeemablePreferredUnitsAdditionalInformationDetails</Role>
      <ShortName>Redeemable Preferred Units - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2411402 - Disclosure - Earnings Per Unit - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EarningsPerUnitAdditionalInformationDetails</Role>
      <ShortName>Earnings Per Unit - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2411403 - Disclosure - Earnings Per Unit - Computation of Basic and Diluted Earnings per Unit (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/EarningsPerUnitComputationOfBasicAndDilutedEarningsPerUnitDetails</Role>
      <ShortName>Earnings Per Unit - Computation of Basic and Diluted Earnings per Unit (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2412401 - Disclosure - AT-THE-MARKET OFFERING PROGRAM (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/AtTheMarketOfferingProgramDetails</Role>
      <ShortName>AT-THE-MARKET OFFERING PROGRAM (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.blackstoneminerals.com/role/AtTheMarketOfferingProgram</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="bsm-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2413401 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.blackstoneminerals.com/role/SubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>bsm-20170630.xml</File>
    <File>bsm-20170630.xsd</File>
    <File>bsm-20170630_cal.xml</File>
    <File>bsm-20170630_def.xml</File>
    <File>bsm-20170630_lab.xml</File>
    <File>bsm-20170630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
