<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>436</ContextCount>
  <ElementCount>467</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>160</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Condensed Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheets</Role>
      <ShortName>Condensed Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001501 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - Statement - Condensed Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedStatementsOfOperations</Role>
      <ShortName>Condensed Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003000 - Statement - Condensed Consolidated Statements of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedStatementsOfEquity</Role>
      <ShortName>Condensed Consolidated Statements of Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1004000 - Statement - Condensed Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - BUSINESS AND ORGANIZATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/BusinessAndOrganization</Role>
      <ShortName>BUSINESS AND ORGANIZATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - SUMMARY OF SIGNIFICANT ACOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/SummaryOfSignificantAcountingPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransaction</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2103100 - Disclosure - REAL ESTATE INVESTMENTS, NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNet</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - INVESTMENT IN UNCONSOLIDATED ENTITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntity</Role>
      <ShortName>INVESTMENT IN UNCONSOLIDATED ENTITY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheetsDetails</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - DEBT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/Debt</Role>
      <ShortName>DEBT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - INTEREST RATE SWAP DERIVATIVES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InterestRateSwapDerivatives</Role>
      <ShortName>INTEREST RATE SWAP DERIVATIVES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RelatedPartyTransactions</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - COMMITMENTS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CommitmentsAndContingencies</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - SUBSEQUENT EVENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/SubsequentEvents</Role>
      <ShortName>SUBSEQUENT EVENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2201201 - Disclosure - SUMMARY OF SIGNIFICANT ACOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/SummaryOfSignificantAcountingPoliciesPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2302301 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionTables</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/MergerAndSelfManagementTransaction</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - REAL ESTATE INVESTMENTS, NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetTables</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/RealEstateInvestmentsNet</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - INVESTMENT IN UNCONSOLIDATED ENTITY (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntityTables</Role>
      <ShortName>INVESTMENT IN UNCONSOLIDATED ENTITY (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntity</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheetsDetailsTables</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheetsDetails</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - DEBT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtTables</Role>
      <ShortName>DEBT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/Debt</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - INTEREST RATE SWAP DERIVATIVES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InterestRateSwapDerivativesTables</Role>
      <ShortName>INTEREST RATE SWAP DERIVATIVES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/InterestRateSwapDerivatives</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - RELATED PARTY TRANSACTIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RelatedPartyTransactionsTables</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/RelatedPartyTransactions</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2309301 - Disclosure - COMMITMENTS AND CONTINGENCIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2401401 - Disclosure - BUSINESS AND ORGANIZATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/BusinessAndOrganizationDetails</Role>
      <ShortName>BUSINESS AND ORGANIZATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/BusinessAndOrganization</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2401402 - Disclosure - SUMMARY OF SIGNIFICANT ACOUNTING POLICIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/SummaryOfSignificantAcountingPoliciesDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACOUNTING POLICIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/SummaryOfSignificantAcountingPoliciesPolicies</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2402402 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionAdditionalInformationDetails</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2402403 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION - REIT I Purchase Price Allocation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionReitIPurchasePriceAllocationDetails</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION - REIT I Purchase Price Allocation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2402404 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION - Class M OP Units Conversion (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionClassMOpUnitsConversionDetails</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION - Class M OP Units Conversion (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2402405 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION - BrixInvest Purchase Price Allocation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionBrixinvestPurchasePriceAllocationDetails</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION - BrixInvest Purchase Price Allocation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2402406 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION - Net Carrying Amount of Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionNetCarryingAmountOfGoodwillDetails</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION - Net Carrying Amount of Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2402407 - Disclosure - MERGER AND SELF-MANAGEMENT TRANSACTION - Other Intangible Assets Acquired (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/MergerAndSelfManagementTransactionOtherIntangibleAssetsAcquiredDetails</Role>
      <ShortName>MERGER AND SELF-MANAGEMENT TRANSACTION - Other Intangible Assets Acquired (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - REAL ESTATE INVESTMENTS, NET - Narative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetNarativeDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Narative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2403403 - Disclosure - REAL ESTATE INVESTMENTS, NET - Summary of Real Estate Properties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetSummaryOfRealEstatePropertiesDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Summary of Real Estate Properties (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2403407 - Disclosure - REAL ESTATE INVESTMENTS, NET - Real Estate Impairment Charges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetRealEstateImpairmentChargesDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Real Estate Impairment Charges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2403408 - Disclosure - REAL ESTATE INVESTMENTS, NET - Revenue Concentration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetRevenueConcentrationDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Revenue Concentration (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2403409 - Disclosure - REAL ESTATE INVESTMENTS, NET - Rental Payments for Operating Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetRentalPaymentsForOperatingLeasesDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Rental Payments for Operating Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2403410 - Disclosure - REAL ESTATE INVESTMENTS, NET - Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetIntangibleAssetsDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2403411 - Disclosure - REAL ESTATE INVESTMENTS, NET - Intangible Assets Amortization (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RealEstateInvestmentsNetIntangibleAssetsAmortizationDetails</Role>
      <ShortName>REAL ESTATE INVESTMENTS, NET - Intangible Assets Amortization (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - INVESTMENT IN UNCONSOLIDATED ENTITY - Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntityInvestmentsDetails</Role>
      <ShortName>INVESTMENT IN UNCONSOLIDATED ENTITY - Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2404403 - Disclosure - INVESTMENT IN UNCONSOLIDATED ENTITY - Entities Equity In Earnings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntityEntitiesEquityInEarningsDetails</Role>
      <ShortName>INVESTMENT IN UNCONSOLIDATED ENTITY - Entities Equity In Earnings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2404404 - Disclosure - INVESTMENT IN UNCONSOLIDATED ENTITY - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntityNarrativeDetails</Role>
      <ShortName>INVESTMENT IN UNCONSOLIDATED ENTITY - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2404405 - Disclosure - INVESTMENT IN UNCONSOLIDATED ENTITY - Summarized Financial Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InvestmentInUnconsolidatedEntitySummarizedFinancialInformationDetails</Role>
      <ShortName>INVESTMENT IN UNCONSOLIDATED ENTITY - Summarized Financial Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS - Tenant Receivables, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheetsDetailsTenantReceivablesNetDetails</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS - Tenant Receivables, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2405403 - Disclosure - CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS - Accounts Payable, Accrued and Other Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CondensedConsolidatedBalanceSheetsDetailsAccountsPayableAccruedAndOtherLiabilitiesDetails</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS DETAILS - Accounts Payable, Accrued and Other Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - DEBT - Schedule of Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtScheduleOfDebtDetails</Role>
      <ShortName>DEBT - Schedule of Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2406403 - Disclosure - DEBT - Mortgage Loan Payable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtMortgageLoanPayableDetails</Role>
      <ShortName>DEBT - Mortgage Loan Payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2406404 - Disclosure - DEBT - Schedule of Line of Credit Facilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtScheduleOfLineOfCreditFacilitiesDetails</Role>
      <ShortName>DEBT - Schedule of Line of Credit Facilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2406405 - Disclosure - DEBT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtNarrativeDetails</Role>
      <ShortName>DEBT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2406406 - Disclosure - DEBT - Maturities of Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtMaturitiesOfLongTermDebtDetails</Role>
      <ShortName>DEBT - Maturities of Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2406407 - Disclosure - DEBT - Interest Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/DebtInterestExpensesDetails</Role>
      <ShortName>DEBT - Interest Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - INTEREST RATE SWAP DERIVATIVES - Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InterestRateSwapDerivativesDerivativeInstrumentsDetails</Role>
      <ShortName>INTEREST RATE SWAP DERIVATIVES - Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - INTEREST RATE SWAP DERIVATIVES - Statement of FInancial Position (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InterestRateSwapDerivativesStatementOfFinancialPositionDetails</Role>
      <ShortName>INTEREST RATE SWAP DERIVATIVES - Statement of FInancial Position (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2407404 - Disclosure - INTEREST RATE SWAP DERIVATIVES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/InterestRateSwapDerivativesNarrativeDetails</Role>
      <ShortName>INTEREST RATE SWAP DERIVATIVES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - RELATED PARTY TRANSACTIONS - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RelatedPartyTransactionsAdditionalInformationDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - RELATED PARTY TRANSACTIONS - Related Party Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/RelatedPartyTransactionsRelatedPartyCostsDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Related Party Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - COMMITMENTS AND CONTINGENCIES - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CommitmentsAndContingenciesAdditionalInformationDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2409403 - Disclosure - COMMITMENTS AND CONTINGENCIES - Maturities of Operating Lease Liability (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/CommitmentsAndContingenciesMaturitiesOfOperatingLeaseLiabilityDetails</Role>
      <ShortName>COMMITMENTS AND CONTINGENCIES - Maturities of Operating Lease Liability (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="cik0001645873-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2410401 - Disclosure - SUBSEQUENT EVENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.RichUncles.com/role/SubsequentEventsDetails</Role>
      <ShortName>SUBSEQUENT EVENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.RichUncles.com/role/SubsequentEvents</ParentRole>
      <Position>61</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>cik0001645873-20200331.xml</File>
    <File>cik0001645873-20200331.xsd</File>
    <File>cik0001645873-20200331_cal.xml</File>
    <File>cik0001645873-20200331_def.xml</File>
    <File>cik0001645873-20200331_lab.xml</File>
    <File>cik0001645873-20200331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
