<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.8.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>602</ContextCount>
  <ElementCount>473</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>204</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>11</UnitCount>
  <MyReports>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - CONSOLIDATED STATEMENTS OF INCOME (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedStatementsOfIncomeUnaudited</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF INCOME (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00300 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedStatementsOfComprehensiveIncomeUnaudited</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00400 - Statement - CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedStatementOfChangesInEquityUnaudited</Role>
      <ShortName>CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00500 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00505 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/StatementConsolidatedStatementsOfCashFlowsUnauditedParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Description of Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDescriptionOfBusiness</Role>
      <ShortName>Description of Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10201 - Disclosure - Basis of Presentation and Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Loans and Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestments</Role>
      <ShortName>Loans and Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Loans Held-for-Sale, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansHeldForSaleNet</Role>
      <ShortName>Loans Held-for-Sale, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10501 - Disclosure - Capitalized Mortgage Servicing Rights</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureCapitalizedMortgageServicingRights</Role>
      <ShortName>Capitalized Mortgage Servicing Rights</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10601 - Disclosure - Mortgage Servicing</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureMortgageServicing</Role>
      <ShortName>Mortgage Servicing</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10701 - Disclosure - Securities Held-to-Maturity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSecuritiesHeldToMaturity</Role>
      <ShortName>Securities Held-to-Maturity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10801 - Disclosure - Investments in Equity Affiliates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureInvestmentsInEquityAffiliates</Role>
      <ShortName>Investments in Equity Affiliates</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10901 - Disclosure - Real Estate Owned</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureRealEstateOwned</Role>
      <ShortName>Real Estate Owned</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>11001 - Disclosure - Debt Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligations</Role>
      <ShortName>Debt Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>11101 - Disclosure - Allowance for Loss-Sharing Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureAllowanceForLossSharingObligations</Role>
      <ShortName>Allowance for Loss-Sharing Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>11201 - Disclosure - Derivative Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDerivativeFinancialInstruments</Role>
      <ShortName>Derivative Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>11301 - Disclosure - Fair Value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValue</Role>
      <ShortName>Fair Value</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>11401 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>11501 - Disclosure - Variable Interest Entities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureVariableInterestEntities</Role>
      <ShortName>Variable Interest Entities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>11601 - Disclosure - Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureEquity</Role>
      <ShortName>Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>11701 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>11801 - Disclosure - Agreements and Transactions with Related Parties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureAgreementsAndTransactionsWithRelatedParties</Role>
      <ShortName>Agreements and Transactions with Related Parties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>11901 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>20202 - Disclosure - Basis of Presentation and Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>30203 - Disclosure - Basis of Presentation and Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesTables</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>30303 - Disclosure - Loans and Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsTables</Role>
      <ShortName>Loans and Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestments</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>30403 - Disclosure - Loans Held-for-Sale, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansHeldForSaleNetTables</Role>
      <ShortName>Loans Held-for-Sale, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureLoansHeldForSaleNet</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>30503 - Disclosure - Capitalized Mortgage Servicing Rights (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureCapitalizedMortgageServicingRightsTables</Role>
      <ShortName>Capitalized Mortgage Servicing Rights (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureCapitalizedMortgageServicingRights</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>30603 - Disclosure - Mortgage Servicing (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureMortgageServicingTables</Role>
      <ShortName>Mortgage Servicing (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureMortgageServicing</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>30703 - Disclosure - Securities Held-to-Maturity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSecuritiesHeldToMaturityTables</Role>
      <ShortName>Securities Held-to-Maturity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureSecuritiesHeldToMaturity</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>30803 - Disclosure - Investments in Equity Affiliates (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureInvestmentsInEquityAffiliatesTables</Role>
      <ShortName>Investments in Equity Affiliates (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureInvestmentsInEquityAffiliates</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>30903 - Disclosure - Real Estate Owned and Held-For-Sale (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureRealEstateOwnedAndHeldForSaleTables</Role>
      <ShortName>Real Estate Owned and Held-For-Sale (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>31003 - Disclosure - Debt Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsTables</Role>
      <ShortName>Debt Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureDebtObligations</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>31103 - Disclosure - Allowance for Loss-Sharing Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureAllowanceForLossSharingObligationsTables</Role>
      <ShortName>Allowance for Loss-Sharing Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureAllowanceForLossSharingObligations</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>31203 - Disclosure - Derivative Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDerivativeFinancialInstrumentsTables</Role>
      <ShortName>Derivative Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureDerivativeFinancialInstruments</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>31303 - Disclosure - Fair Value (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueTables</Role>
      <ShortName>Fair Value (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureFairValue</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>31503 - Disclosure - Variable Interest Entities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureVariableInterestEntitiesTables</Role>
      <ShortName>Variable Interest Entities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureVariableInterestEntities</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>31603 - Disclosure - Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureEquityTables</Role>
      <ShortName>Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureEquity</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>31903 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureSegmentInformation</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>40101 - Disclosure - Description of Business (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDescriptionOfBusinessDetails</Role>
      <ShortName>Description of Business (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureDescriptionOfBusiness</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>40201 - Disclosure - Basis of Presentation and Significant Accounting Policies, Recently Adopted Accounting Pronouncements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesRecentlyAdoptedAccountingPronouncementsDetails</Role>
      <ShortName>Basis of Presentation and Significant Accounting Policies, Recently Adopted Accounting Pronouncements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Loans and Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsDetails</Role>
      <ShortName>Loans and Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>40302 - Disclosure - Loans and Investments, Risk Ratings and LTV Ratios (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsRiskRatingsAndLtvRatiosDetails</Role>
      <ShortName>Loans and Investments, Risk Ratings and LTV Ratios (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>40303 - Disclosure - Loans and Investments, Impaired Loans and Allowance for Loan Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsImpairedLoansAndAllowanceForLoanLossesDetails</Role>
      <ShortName>Loans and Investments, Impaired Loans and Allowance for Loan Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>40304 - Disclosure - Loans and Investments, Charge-offs and Recoveries Narratives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsChargeOffsAndRecoveriesNarrativesDetails</Role>
      <ShortName>Loans and Investments, Charge-offs and Recoveries Narratives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>40305 - Disclosure - Loans and Investments, Summary of impaired loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsSummaryOfImpairedLoansDetails</Role>
      <ShortName>Loans and Investments, Summary of impaired loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>40306 - Disclosure - Loans and Investments, Non-performing Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsNonPerformingLoansDetails</Role>
      <ShortName>Loans and Investments, Non-performing Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>40307 - Disclosure - Loans and Investments, Interest Reserves (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansAndInvestmentsInterestReservesDetails</Role>
      <ShortName>Loans and Investments, Interest Reserves (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Loans Held-for-Sale, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureLoansHeldForSaleNetDetails</Role>
      <ShortName>Loans Held-for-Sale, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureLoansHeldForSaleNetTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>40501 - Disclosure - Capitalized Mortgage Servicing Rights (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureCapitalizedMortgageServicingRightsDetails</Role>
      <ShortName>Capitalized Mortgage Servicing Rights (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureCapitalizedMortgageServicingRightsTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>40601 - Disclosure - Mortgage Servicing (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureMortgageServicingDetails</Role>
      <ShortName>Mortgage Servicing (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureMortgageServicingTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>40701 - Disclosure - Securities Held-to-Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSecuritiesHeldToMaturityDetails</Role>
      <ShortName>Securities Held-to-Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureSecuritiesHeldToMaturityTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>40801 - Disclosure - Investments in Equity Affiliates, Summary (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureInvestmentsInEquityAffiliatesSummaryDetails</Role>
      <ShortName>Investments in Equity Affiliates, Summary (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>40802 - Disclosure - Investments in Equity Affiliates, Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureInvestmentsInEquityAffiliatesAdditionalInformationDetails</Role>
      <ShortName>Investments in Equity Affiliates, Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>40901 - Disclosure - Real Estate Owned, Portfolio (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureRealEstateOwnedPortfolioDetails</Role>
      <ShortName>Real Estate Owned, Portfolio (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>41001 - Disclosure - Debt Obligations, Credit Facilities and Repurchase Agreements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsCreditFacilitiesAndRepurchaseAgreementsDetails</Role>
      <ShortName>Debt Obligations, Credit Facilities and Repurchase Agreements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>41002 - Disclosure - Debt Obligations, Collateralized Loan Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsCollateralizedLoanObligationsDetails</Role>
      <ShortName>Debt Obligations, Collateralized Loan Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>41003 - Disclosure - Debt Obligations, Luxembourg Debt Fund (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsLuxembourgDebtFundDetails</Role>
      <ShortName>Debt Obligations, Luxembourg Debt Fund (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>41004 - Disclosure - Debt Obligations, Senior Unsecured Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsSeniorUnsecuredNotesDetails</Role>
      <ShortName>Debt Obligations, Senior Unsecured Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>41005 - Disclosure - Debt Obligations, Convertible Senior Unsecured Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsConvertibleSeniorUnsecuredNotesDetails</Role>
      <ShortName>Debt Obligations, Convertible Senior Unsecured Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>41006 - Disclosure - Debt Obligations, Junior Subordinated Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsJuniorSubordinatedNotesDetails</Role>
      <ShortName>Debt Obligations, Junior Subordinated Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>41007 - Disclosure - Debt Obligations, Related Party Financing (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsRelatedPartyFinancingDetails</Role>
      <ShortName>Debt Obligations, Related Party Financing (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>41008 - Disclosure - Debt Obligations, Debt Covenants (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDebtObligationsDebtCovenantsDetails</Role>
      <ShortName>Debt Obligations, Debt Covenants (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>41101 - Disclosure - Allowance for Loss-Sharing Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureAllowanceForLossSharingObligationsDetails</Role>
      <ShortName>Allowance for Loss-Sharing Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureAllowanceForLossSharingObligationsTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>41201 - Disclosure - Derivative Financial Instruments, Agency Business (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureDerivativeFinancialInstrumentsAgencyBusinessDetails</Role>
      <ShortName>Derivative Financial Instruments, Agency Business (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>41301 - Disclosure - Fair Value, Carrying Value and Estimated Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueCarryingValueAndEstimatedFairValueDetails</Role>
      <ShortName>Fair Value, Carrying Value and Estimated Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>41302 - Disclosure - Fair Value, Measurement on Recurring and Nonrecurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueMeasurementOnRecurringAndNonrecurringBasisDetails</Role>
      <ShortName>Fair Value, Measurement on Recurring and Nonrecurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>41303 - Disclosure - Fair Value, Level 3 Inputs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueLevel3InputsDetails</Role>
      <ShortName>Fair Value, Level 3 Inputs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>41304 - Disclosure - Fair Value, Level 3 Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueLevel3DerivativeInstrumentsDetails</Role>
      <ShortName>Fair Value, Level 3 Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>41305 - Disclosure - Fair Value, Components of fair value and other relevant information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueComponentsOfFairValueAndOtherRelevantInformationDetails</Role>
      <ShortName>Fair Value, Components of fair value and other relevant information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>41306 - Disclosure - Fair Value, Financial Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureFairValueFinancialAssetsAndLiabilitiesDetails</Role>
      <ShortName>Fair Value, Financial Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>41401 - Disclosure - Commitments and Contingencies, Contractual Commitments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureCommitmentsAndContingenciesContractualCommitmentsDetails</Role>
      <ShortName>Commitments and Contingencies, Contractual Commitments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>41402 - Disclosure - Commitments and Contingencies, Litigation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureCommitmentsAndContingenciesLitigationDetails</Role>
      <ShortName>Commitments and Contingencies, Litigation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>41501 - Disclosure - Variable Interest Entities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureVariableInterestEntitiesDetails</Role>
      <ShortName>Variable Interest Entities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureVariableInterestEntitiesTables</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>41601 - Disclosure - Equity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureEquityDetails</Role>
      <ShortName>Equity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureEquityTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>41602 - Disclosure - Equity, Earnings Per Share ("EPS") (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureEquityEarningsPerShareepsDetails</Role>
      <ShortName>Equity, Earnings Per Share ("EPS") (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>41701 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureIncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureIncomeTaxes</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>41801 - Disclosure - Agreements and Transactions with Related Parties, Management Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureAgreementsAndTransactionsWithRelatedPartiesManagementAgreementDetails</Role>
      <ShortName>Agreements and Transactions with Related Parties, Management Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>41802 - Disclosure - Agreements and Transactions with Related Parties, Other (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureAgreementsAndTransactionsWithRelatedPartiesOtherDetails</Role>
      <ShortName>Agreements and Transactions with Related Parties, Other (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.arborrealtytrust.com/role/DisclosureAgreementsAndTransactionsWithRelatedParties</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>41901 - Disclosure - Segment Information - Statements of Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSegmentInformationStatementsOfIncomeDetails</Role>
      <ShortName>Segment Information - Statements of Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>41902 - Disclosure - Segment Information - Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSegmentInformationBalanceSheetDetails</Role>
      <ShortName>Segment Information - Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>41903 - Disclosure - Segment Information - Origination Data (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSegmentInformationOriginationDataDetails</Role>
      <ShortName>Segment Information - Origination Data (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="abr-20180331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>41904 - Disclosure - Segment Information - Key Servicing Metrics (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.arborrealtytrust.com/role/DisclosureSegmentInformationKeyServicingMetricsDetails</Role>
      <ShortName>Segment Information - Key Servicing Metrics (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>abr-20180331.xml</File>
    <File>abr-20180331.xsd</File>
    <File>abr-20180331_cal.xml</File>
    <File>abr-20180331_def.xml</File>
    <File>abr-20180331_lab.xml</File>
    <File>abr-20180331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/stpr/2011-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2014-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2017-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/invest/2013-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
