<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>232</ContextCount>
  <ElementCount>306</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>61</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001001 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/DocumentandEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001002 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002003 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003004 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004005 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005006 - Statement - CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS EQUITY/ PARTNER'S CAPITAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDSTATEMENTOFCHANGESINSTOCKHOLDERSEQUITYPARTNERSCAPITAL</Role>
      <ShortName>CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS EQUITY/ PARTNER'S CAPITAL</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1006007 - Statement - CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY / PARTNERS' CAPITAL (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDSTATEMENTOFCHANGESINSTOCKHOLDERSEQUITYPARTNERSCAPITALParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY / PARTNERS' CAPITAL (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1007008 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2101101 - Disclosure - Organization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/Organization</Role>
      <ShortName>Organization</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2103102 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2107103 - Disclosure - Investment in Real Estate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/InvestmentinRealEstate</Role>
      <ShortName>Investment in Real Estate</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2111104 - Disclosure - Indebtedness</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/Indebtedness</Role>
      <ShortName>Indebtedness</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2117105 - Disclosure - Variable Interest Entities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/VariableInterestEntities</Role>
      <ShortName>Variable Interest Entities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2121106 - Disclosure - Stockholders??? Equity of the Company and Partners' Capital of the Operating Partnership</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/StockholdersEquityoftheCompanyandPartnersCapitaloftheOperatingPartnership</Role>
      <ShortName>Stockholders??? Equity of the Company and Partners' Capital of the Operating Partnership</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2125107 - Disclosure - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Accumulated Other Comprehensive Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2130108 - Disclosure - Earnings Per Share / Unit (EPS / EPU)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPU</Role>
      <ShortName>Earnings Per Share / Unit (EPS / EPU)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2134109 - Disclosure - Long-Term Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/LongTermCompensation</Role>
      <ShortName>Long-Term Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2136110 - Disclosure - Derivatives</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/Derivatives</Role>
      <ShortName>Derivatives</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2140111 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/RelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2142112 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2144113 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2204201 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/SummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2308302 - Disclosure - Investment in Real Estate Investment in Real Estate (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/InvestmentinRealEstateInvestmentinRealEstateTables</Role>
      <ShortName>Investment in Real Estate Investment in Real Estate (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2312303 - Disclosure - Indebtedness (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/IndebtednessTables</Role>
      <ShortName>Indebtedness (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/Indebtedness</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2318304 - Disclosure - Variable Interest Entities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/VariableInterestEntitiesTables</Role>
      <ShortName>Variable Interest Entities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/VariableInterestEntities</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2326306 - Disclosure - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncome</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2331307 - Disclosure - Earnings Per Share / Unit (EPS / EPU) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPUTables</Role>
      <ShortName>Earnings Per Share / Unit (EPS / EPU) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPU</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2337308 - Disclosure - Derivatives (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/DerivativesTables</Role>
      <ShortName>Derivatives (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/Derivatives</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2402401 - Disclosure - Organization - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/OrganizationAdditionalInformationDetails</Role>
      <ShortName>Organization - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2409403 - Disclosure - Investment in Real Estate - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/InvestmentinRealEstateAdditionalInformationDetails</Role>
      <ShortName>Investment in Real Estate - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Investment in Real Estate Investment in Real Estate - Summary of Purchase Price Allocation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/InvestmentinRealEstateInvestmentinRealEstateSummaryofPurchasePriceAllocationDetails</Role>
      <ShortName>Investment in Real Estate Investment in Real Estate - Summary of Purchase Price Allocation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2413405 - Disclosure - Indebtedness - Summary of Indebtedness (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/IndebtednessSummaryofIndebtednessDetails</Role>
      <ShortName>Indebtedness - Summary of Indebtedness (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2414406 - Disclosure - Indebtedness - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/IndebtednessAdditionalInformationDetails</Role>
      <ShortName>Indebtedness - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2415407 - Disclosure - Indebtedness - Schedule of Maturities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/IndebtednessScheduleofMaturitiesDetails</Role>
      <ShortName>Indebtedness - Schedule of Maturities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2416408 - Disclosure - Indebtedness - Summary of Indebtedness at Estimated Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/IndebtednessSummaryofIndebtednessatEstimatedFairValueDetails</Role>
      <ShortName>Indebtedness - Summary of Indebtedness at Estimated Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2419409 - Disclosure - Variable Interest Entities - Summarized Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/VariableInterestEntitiesSummarizedBalanceSheetDetails</Role>
      <ShortName>Variable Interest Entities - Summarized Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2420410 - Disclosure - Variable Interest Entities - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/VariableInterestEntitiesAdditionalInformationDetails</Role>
      <ShortName>Variable Interest Entities - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2423411 - Disclosure - Stockholders??? Equity of the Company and Partners' Capital of the Operating Partnership - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/StockholdersEquityoftheCompanyandPartnersCapitaloftheOperatingPartnershipAdditionalInformationDetails</Role>
      <ShortName>Stockholders??? Equity of the Company and Partners' Capital of the Operating Partnership - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2427413 - Disclosure - Accumulated Other Comprehensive Income (Changes in AOCI) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncomeChangesinAOCIDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Changes in AOCI) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2428414 - Disclosure - Accumulated Other Comprehensive Income (Amounts Reclassified from AOCI) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncomeAmountsReclassifiedfromAOCIDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Amounts Reclassified from AOCI) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2429415 - Disclosure - Accumulated Other Comprehensive Income - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/AccumulatedOtherComprehensiveIncomeAdditionalInformationDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2432416 - Disclosure - Earnings Per Share / Unit (EPS / EPU) - Computation of Basic and Diluted EPS / EPU (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPUComputationofBasicandDilutedEPSEPUDetails</Role>
      <ShortName>Earnings Per Share / Unit (EPS / EPU) - Computation of Basic and Diluted EPS / EPU (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPUTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2433417 - Disclosure - Earnings Per Share / Unit (EPS / EPU) - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPUAdditionalInformationDetails</Role>
      <ShortName>Earnings Per Share / Unit (EPS / EPU) - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstindustrial.com/role/EarningsPerShareUnitEPSEPUTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2435418 - Disclosure - Long-Term Compensation - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/LongTermCompensationAdditionalInformationDetails</Role>
      <ShortName>Long-Term Compensation - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2438419 - Disclosure - Derivatives - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/DerivativesAdditionalInformationDetails</Role>
      <ShortName>Derivatives - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2439420 - Disclosure - Derivatives - Fair Value Measurements on Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/DerivativesFairValueMeasurementsonRecurringBasisDetails</Role>
      <ShortName>Derivatives - Fair Value Measurements on Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2441421 - Disclosure - Related Party Transactions Related Party Transactions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/RelatedPartyTransactionsRelatedPartyTransactionsAdditionalInformationDetails</Role>
      <ShortName>Related Party Transactions Related Party Transactions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2443422 - Disclosure - Commitments and Contingencies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/CommitmentsandContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="fr-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2445423 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstindustrial.com/role/SubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</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="fr-20200630.htm">fr-20200630.htm</File>
    <File>fr-20200630.xsd</File>
    <File>fr-20200630_cal.xml</File>
    <File>fr-20200630_def.xml</File>
    <File>fr-20200630_lab.xml</File>
    <File>fr-20200630_pre.xml</File>
    <File>fr-2020630xex311.htm</File>
    <File>fr-2020630xex312.htm</File>
    <File>fr-2020630xex313.htm</File>
    <File>fr-2020630xex314.htm</File>
    <File>fr-2020630xex321.htm</File>
    <File>fr-2020630xex322.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>fr-20200630_g1.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
