<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>133</ContextCount>
  <ElementCount>309</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>52</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001002 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002003 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003004 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004005 - Statement - CONSOLIDATED STATEMENTS OF EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CONSOLIDATEDSTATEMENTSOFEQUITY</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005006 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2101101 - Disclosure - Organization and Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/OrganizationandBusiness</Role>
      <ShortName>Organization and Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2103102 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2106103 - Disclosure - Real Estate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RealEstate</Role>
      <ShortName>Real Estate</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2111104 - Disclosure - Accrued Rent and Accounts Receivable, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/AccruedRentandAccountsReceivablenet</Role>
      <ShortName>Accrued Rent and Accounts Receivable, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2115105 - Disclosure - Deferred Leasing Commission Costs, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/DeferredLeasingCommissionCostsnet</Role>
      <ShortName>Deferred Leasing Commission Costs, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2118106 - Disclosure - Future Minimum Rents</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/FutureMinimumRents</Role>
      <ShortName>Future Minimum Rents</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2121107 - Disclosure - Notes Payable</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://hartmaninvestment.com/role/NotesPayable</Role>
      <ShortName>Notes Payable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2126108 - Disclosure - Income Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncomePerShare</Role>
      <ShortName>Income Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2129109 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2131110 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2133111 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/StockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2137112 - Disclosure - Incentive Award Plan</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncentiveAwardPlan</Role>
      <ShortName>Incentive Award Plan</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2139113 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2140114 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2204201 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/SummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Real Estate (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RealEstateTables</Role>
      <ShortName>Real Estate (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/RealEstate</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2312302 - Disclosure - Accrued Rent and Accounts Receivable, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/AccruedRentandAccountsReceivablenetTables</Role>
      <ShortName>Accrued Rent and Accounts Receivable, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/AccruedRentandAccountsReceivablenet</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2316303 - Disclosure - Deferred Leasing Commission Costs, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/DeferredLeasingCommissionCostsnetTables</Role>
      <ShortName>Deferred Leasing Commission Costs, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/DeferredLeasingCommissionCostsnet</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2319304 - Disclosure - Future Minimum Rents (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/FutureMinimumRentsTables</Role>
      <ShortName>Future Minimum Rents (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/FutureMinimumRents</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2322305 - Disclosure - Notes Payable (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://hartmaninvestment.com/role/NotesPayableTables</Role>
      <ShortName>Notes Payable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/NotesPayable</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2327306 - Disclosure - Income Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncomePerShareTables</Role>
      <ShortName>Income Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/IncomePerShare</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2334307 - Disclosure - Stockholders' Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/StockholdersEquityTables</Role>
      <ShortName>Stockholders' Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/StockholdersEquity</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2402401 - Disclosure - Organization and Business (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/OrganizationandBusinessDetails</Role>
      <ShortName>Organization and Business (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/OrganizationandBusiness</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Summary of Significant Accounting Policies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/SummaryofSignificantAccountingPoliciesDetails</Role>
      <ShortName>Summary of Significant Accounting Policies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/SummaryofSignificantAccountingPoliciesPolicies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - Real Estate - Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RealEstateAssetsDetails</Role>
      <ShortName>Real Estate - Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2409404 - Disclosure - Real Estate - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RealEstateAdditionalInformationDetails</Role>
      <ShortName>Real Estate - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2410405 - Disclosure - Real Estate - In-place Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RealEstateInplaceIntangibleAssetsDetails</Role>
      <ShortName>Real Estate - In-place Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2413406 - Disclosure - Accrued Rent and Accounts Receivable, net - Summary of Accounts Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/AccruedRentandAccountsReceivablenetSummaryofAccountsReceivableDetails</Role>
      <ShortName>Accrued Rent and Accounts Receivable, net - Summary of Accounts Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2414407 - Disclosure - Accrued Rent and Accounts Receivable, net - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/AccruedRentandAccountsReceivablenetAdditionalInformationDetails</Role>
      <ShortName>Accrued Rent and Accounts Receivable, net - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2417408 - Disclosure - Deferred Leasing Commission Costs, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/DeferredLeasingCommissionCostsnetDetails</Role>
      <ShortName>Deferred Leasing Commission Costs, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/DeferredLeasingCommissionCostsnetTables</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2420409 - Disclosure - Future Minimum Rents (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/FutureMinimumRentsDetails</Role>
      <ShortName>Future Minimum Rents (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/FutureMinimumRentsTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2423410 - Disclosure - Notes Payable - Additional Information (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://hartmaninvestment.com/role/NotesPayableAdditionalInformationDetails</Role>
      <ShortName>Notes Payable - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2424411 - Disclosure - Notes Payable - Summary of Notes Payable (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://hartmaninvestment.com/role/NotesPayableSummaryofNotesPayableDetails</Role>
      <ShortName>Notes Payable - Summary of Notes Payable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2425412 - Disclosure - Notes Payable - Deferred Loan Costs (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://hartmaninvestment.com/role/NotesPayableDeferredLoanCostsDetails</Role>
      <ShortName>Notes Payable - Deferred Loan Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2428413 - Disclosure - Income Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncomePerShareDetails</Role>
      <ShortName>Income Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/IncomePerShareTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2430414 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/IncomeTaxes</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2432415 - Disclosure - Related Party Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/RelatedPartyTransactionsDetails</Role>
      <ShortName>Related Party Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/RelatedPartyTransactions</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2435416 - Disclosure - Stockholders' Equity - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/StockholdersEquityNarrativeDetails</Role>
      <ShortName>Stockholders' Equity - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2436417 - Disclosure - Stockholders' Equity - Distributions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/StockholdersEquityDistributionsDetails</Role>
      <ShortName>Stockholders' Equity - Distributions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="fil-20200331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2438418 - Disclosure - Incentive Award Plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://hartmaninvestment.com/role/IncentiveAwardPlanDetails</Role>
      <ShortName>Incentive Award Plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://hartmaninvestment.com/role/IncentiveAwardPlan</ParentRole>
      <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 doctype="10-Q" original="fil-20200331.htm">fil-20200331.htm</File>
    <File>fil-20200331.xsd</File>
    <File>fil-20200331_cal.xml</File>
    <File>fil-20200331_def.xml</File>
    <File>fil-20200331_lab.xml</File>
    <File>fil-20200331_pre.xml</File>
    <File>xxexhibit3112020q1.htm</File>
    <File>xxexhibit3122020q1.htm</File>
    <File>xxexhibit3212020q1new.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/stpr/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2018-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
