<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>266</ContextCount>
  <ElementCount>348</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>70</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>11</UnitCount>
  <MyReports>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>1001 - Document - Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/Cover</Role>
      <ShortName>Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1002 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1003 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1004 - Statement - Conolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/ConolidatedStatementsOfOperations</Role>
      <ShortName>Conolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1005 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Deficit)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/ConsolidatedStatementsOfChangesInStockholdersEquityDeficit</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity (Deficit)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1006 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1007 - Disclosure - Organization and Business Purpose</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/OrganizationAndBusinessPurpose</Role>
      <ShortName>Organization and Business Purpose</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1008 - Disclosure - Capitalization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/Capitalization</Role>
      <ShortName>Capitalization</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>1009 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>1010 - Disclosure - Investments in Real Estate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentsInRealEstate</Role>
      <ShortName>Investments in Real Estate</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>1011 - Disclosure - Intangibles</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/Intangibles</Role>
      <ShortName>Intangibles</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>1012 - Disclosure - Investment in Real Estate-Related Loan</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentInRealEstateRelatedLoan</Role>
      <ShortName>Investment in Real Estate-Related Loan</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>1013 - Disclosure - Accounts and Other Receivables and Other Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/AccountsAndOtherReceivablesAndOtherAssets</Role>
      <ShortName>Accounts and Other Receivables and Other Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>1014 - Disclosure - Accounts Payable, Accrued Expenses and Other Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/AccountsPayableAccruedExpensesAndOtherLiabilities</Role>
      <ShortName>Accounts Payable, Accrued Expenses and Other Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>1015 - Disclosure - Mortgage Loans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/MortgageLoans</Role>
      <ShortName>Mortgage Loans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>1016 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/RelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>1017 - Disclosure - Stockholder's Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/StockholdersEquity</Role>
      <ShortName>Stockholder's Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>1018 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>1019 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>1020 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>1021 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://oak.com/role/SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>1022 - Disclosure - Capitalization (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/CapitalizationTables</Role>
      <ShortName>Capitalization (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/Capitalization</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>1023 - Disclosure - Investments in Real Estate (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentsInRealEstateTables</Role>
      <ShortName>Investments in Real Estate (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/InvestmentsInRealEstate</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>1024 - Disclosure - Intangibles (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/IntangiblesTables</Role>
      <ShortName>Intangibles (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/Intangibles</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>1025 - Disclosure - Investment in Real Estate-Related Loan (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentInRealEstateRelatedLoanTables</Role>
      <ShortName>Investment in Real Estate-Related Loan (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/InvestmentInRealEstateRelatedLoan</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>1026 - Disclosure - Accounts and Other Receivables and Other Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/AccountsAndOtherReceivablesAndOtherAssetsTables</Role>
      <ShortName>Accounts and Other Receivables and Other Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/AccountsAndOtherReceivablesAndOtherAssets</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>1027 - Disclosure - Accounts Payable, Accrued Expenses and Other Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/AccountsPayableAccruedExpensesAndOtherLiabilitiesTables</Role>
      <ShortName>Accounts Payable, Accrued Expenses and Other Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/AccountsPayableAccruedExpensesAndOtherLiabilities</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>1028 - Disclosure - Mortgage Loans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/MortgageLoansTables</Role>
      <ShortName>Mortgage Loans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/MortgageLoans</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>1029 - Disclosure - Stockholder's Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/StockholderSEquityTables</Role>
      <ShortName>Stockholder's Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/StockholdersEquity</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>1030 - Disclosure - Segment Reporting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SegmentReportingTables</Role>
      <ShortName>Segment Reporting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/SegmentReporting</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>1031 - Disclosure - Subsequent Events (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SubsequentEventsTables</Role>
      <ShortName>Subsequent Events (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://oak.com/role/SubsequentEvents</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>1032 - Disclosure - Organization and Business Purpose - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/OrganizationAndBusinessPurposeAdditionalInformationDetail</Role>
      <ShortName>Organization and Business Purpose - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>1033 - Disclosure - Capitalization - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/CapitalizationAdditionalInformationDetail</Role>
      <ShortName>Capitalization - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>1034 - Disclosure - Capitalization - Summary of Classes of Common Stock Authorized (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/CapitalizationSummaryOfClassesOfCommonStockAuthorizedDetail</Role>
      <ShortName>Capitalization - Summary of Classes of Common Stock Authorized (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>1035 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SummaryOfSignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Summary of Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>1036 - Disclosure - Summary of Significant Accounting Policies VIE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SummaryOfSignificantAccountingPoliciesVieDetails</Role>
      <ShortName>Summary of Significant Accounting Policies VIE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/SummaryOfSignificantAccountingPoliciesPolicies</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>1037 - Disclosure - Summary of Significant Accounting Policies Restricted cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SummaryOfSignificantAccountingPoliciesRestrictedCashDetails</Role>
      <ShortName>Summary of Significant Accounting Policies Restricted cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>1038 - Disclosure - Investments in Real Estate - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentsInRealEstateAdditionalInformationDetail</Role>
      <ShortName>Investments in Real Estate - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>1039 - Disclosure - Investments in Real Estate (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentsInRealEstateDetail</Role>
      <ShortName>Investments in Real Estate (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/InvestmentsInRealEstateTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>1040 - Disclosure - Investments in Real Estate Assets Acquired Liabilities Assumed (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentsInRealEstateAssetsAcquiredLiabilitiesAssumedDetails</Role>
      <ShortName>Investments in Real Estate Assets Acquired Liabilities Assumed (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>1041 - Disclosure - Intangibles (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/IntangiblesDetails</Role>
      <ShortName>Intangibles (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/IntangiblesTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>1042 - Disclosure - Intangibles - Future Amortization (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/IntangiblesFutureAmortizationDetails</Role>
      <ShortName>Intangibles - Future Amortization (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>1043 - Disclosure - Investment in Real Estate-Related Loan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentInRealEstateRelatedLoanDetails</Role>
      <ShortName>Investment in Real Estate-Related Loan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/InvestmentInRealEstateRelatedLoanTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>1044 - Disclosure - Investment in Real Estate-Related Loan - Schedule of Real Estate Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentInRealEstateRelatedLoanScheduleOfRealEstateLoansDetails</Role>
      <ShortName>Investment in Real Estate-Related Loan - Schedule of Real Estate Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>1045 - Disclosure - Investment in Real Estate-Related Loan - Floating Rate CMBS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/InvestmentInRealEstateRelatedLoanFloatingRateCmbsDetails</Role>
      <ShortName>Investment in Real Estate-Related Loan - Floating Rate CMBS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>1046 - Disclosure - Accounts and Other Receivables and Other Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/AccountsAndOtherReceivablesAndOtherAssetsDetails</Role>
      <ShortName>Accounts and Other Receivables and Other Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/AccountsAndOtherReceivablesAndOtherAssetsTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>1047 - Disclosure - Accounts Payable, Accrued Expenses and Other Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/AccountsPayableAccruedExpensesAndOtherLiabilitiesDetails</Role>
      <ShortName>Accounts Payable, Accrued Expenses and Other Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/AccountsPayableAccruedExpensesAndOtherLiabilitiesTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>1048 - Disclosure - Mortgage Loans - Schedule of Mortgage Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/MortgageLoansScheduleOfMortgageLoansDetails</Role>
      <ShortName>Mortgage Loans - Schedule of Mortgage Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>1049 - Disclosure - Mortgage Loans - Schedule of Future Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/MortgageLoansScheduleOfFuturePaymentsDetails</Role>
      <ShortName>Mortgage Loans - Schedule of Future Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>1050 - Disclosure - Related Party Transactions - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/RelatedPartyTransactionsAdditionalInformationDetail</Role>
      <ShortName>Related Party Transactions - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>1051 - Disclosure - Stockholder's Equity - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/StockholdersEquityAdditionalInformationDetail</Role>
      <ShortName>Stockholder's Equity - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>1052 - Disclosure - Stockholder's Equity - Schedule of Common and Preferred Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/StockholdersEquityScheduleOfCommonAndPreferredStockDetails</Role>
      <ShortName>Stockholder's Equity - Schedule of Common and Preferred Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>1053 - Disclosure - Stockholder's Equity - Common Stock Rollforward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/StockholdersEquityCommonStockRollforwardDetails</Role>
      <ShortName>Stockholder's Equity - Common Stock Rollforward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>1054 - Disclosure - Stockholder's Equity - Dividends (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/StockholdersEquityDividendsDetails</Role>
      <ShortName>Stockholder's Equity - Dividends (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>1055 - Disclosure - Segment Reporting (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SegmentReportingDetails</Role>
      <ShortName>Segment Reporting (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://oak.com/role/SegmentReportingTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>1056 - Disclosure - Subsequent Events - Distributions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SubsequentEventsDistributionsDetails</Role>
      <ShortName>Subsequent Events - Distributions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="cik0001713407-20200630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>1057 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://oak.com/role/SubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>cik0001713407-20200630.xml</File>
    <File>cik0001713407-20200630.xsd</File>
    <File>cik0001713407-20200630_cal.xml</File>
    <File>cik0001713407-20200630_def.xml</File>
    <File>cik0001713407-20200630_lab.xml</File>
    <File>cik0001713407-20200630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
