<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Version>2.4.0.8</Version>
  <ProcessingTime />
  <ReportFormat>HtmlAndXml</ReportFormat>
  <ContextCount>220</ContextCount>
  <ElementCount>315</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>106</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <XmlFileName>R1.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Consolidated Balance Sheets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/ConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>Consolidated Balance Sheets (Unaudited)</ShortName>
      <XmlFileName>R2.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002000 - Statement - Consolidated Statements of Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/ConsolidatedStatementsOfIncomeUnaudited</Role>
      <ShortName>Consolidated Statements of Income (Unaudited)</ShortName>
      <XmlFileName>R3.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003000 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/ConsolidatedStatementsOfComprehensiveIncomeUnaudited</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Unaudited)</ShortName>
      <XmlFileName>R4.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004000 - Statement - Consolidated Statement of Changes in Stockholders' Equity and Noncontrolling Interests (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/ConsolidatedStatementOfChangesInStockholdersEquityAndNoncontrollingInterestsUnaudited</Role>
      <ShortName>Consolidated Statement of Changes in Stockholders' Equity and Noncontrolling Interests (Unaudited)</ShortName>
      <XmlFileName>R5.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005000 - Statement - Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/ConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <XmlFileName>R6.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - Background</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/Background</Role>
      <ShortName>Background</ShortName>
      <XmlFileName>R7.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2103100 - Disclosure - Basis of presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/BasisOfPresentation</Role>
      <ShortName>Basis of presentation</ShortName>
      <XmlFileName>R8.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - Investments in real estate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsInRealEstate</Role>
      <ShortName>Investments in real estate</ShortName>
      <XmlFileName>R9.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/Investments</Role>
      <ShortName>Investments</ShortName>
      <XmlFileName>R10.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - Secured and unsecured senior debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SecuredAndUnsecuredSeniorDebt</Role>
      <ShortName>Secured and unsecured senior debt</ShortName>
      <XmlFileName>R11.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Interest rate swap agreements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InterestRateSwapAgreements</Role>
      <ShortName>Interest rate swap agreements</ShortName>
      <XmlFileName>R12.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - Fair value measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/FairValueMeasurements</Role>
      <ShortName>Fair value measurements</ShortName>
      <XmlFileName>R13.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - Earnings per share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/EarningsPerShare</Role>
      <ShortName>Earnings per share</ShortName>
      <XmlFileName>R14.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Net income attributable to Alexandria Real Estate Equities, Inc.</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/NetIncomeAttributableToAlexandriaRealEstateEquitiesInc</Role>
      <ShortName>Net income attributable to Alexandria Real Estate Equities, Inc.</ShortName>
      <XmlFileName>R15.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2111100 - Disclosure - Stockholders' equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/StockholdersEquity</Role>
      <ShortName>Stockholders' equity</ShortName>
      <XmlFileName>R16.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - Noncontrolling interests</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/NoncontrollingInterests</Role>
      <ShortName>Noncontrolling interests</ShortName>
      <XmlFileName>R17.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2114100 - Disclosure - Discontinued operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/DiscontinuedOperations</Role>
      <ShortName>Discontinued operations</ShortName>
      <XmlFileName>R18.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2115100 - Disclosure - Subsequent events (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.are.com/role/SubsequentEventsNotes</Role>
      <ShortName>Subsequent events (Notes)</ShortName>
      <XmlFileName>R19.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - Condensed consolidating financial information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/CondensedConsolidatingFinancialInformation</Role>
      <ShortName>Condensed consolidating financial information</ShortName>
      <XmlFileName>R20.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2203201 - Disclosure - Basis of presentation (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/BasisOfPresentationPolicies</Role>
      <ShortName>Basis of presentation (Policies)</ShortName>
      <XmlFileName>R21.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - Investments in real estate (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsInRealEstateTables</Role>
      <ShortName>Investments in real estate (Tables)</ShortName>
      <XmlFileName>R22.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <XmlFileName>R23.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - Secured and unsecured senior debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SecuredAndUnsecuredSeniorDebtTables</Role>
      <ShortName>Secured and unsecured senior debt (Tables)</ShortName>
      <XmlFileName>R24.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Interest rate swap agreements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InterestRateSwapAgreementsTables</Role>
      <ShortName>Interest rate swap agreements (Tables)</ShortName>
      <XmlFileName>R25.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - Fair value measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair value measurements (Tables)</ShortName>
      <XmlFileName>R26.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2309301 - Disclosure - Earnings per share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings per share (Tables)</ShortName>
      <XmlFileName>R27.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - Net income attributable to Alexandria Real Estate Equities, Inc. (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/NetIncomeAttributableToAlexandriaRealEstateEquitiesIncTables</Role>
      <ShortName>Net income attributable to Alexandria Real Estate Equities, Inc. (Tables)</ShortName>
      <XmlFileName>R28.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2311301 - Disclosure - Stockholders' equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/StockholdersEquityTables</Role>
      <ShortName>Stockholders' equity (Tables)</ShortName>
      <XmlFileName>R29.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2314301 - Disclosure - Discontinued operations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/DiscontinuedOperationsTables</Role>
      <ShortName>Discontinued operations (Tables)</ShortName>
      <XmlFileName>R30.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2315301 - Disclosure - Subsequent events (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SubsequentEventsTables</Role>
      <ShortName>Subsequent events (Tables)</ShortName>
      <XmlFileName>R31.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - Condensed consolidating financial information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/CondensedConsolidatingFinancialInformationTables</Role>
      <ShortName>Condensed consolidating financial information (Tables)</ShortName>
      <XmlFileName>R32.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - Basis of presentation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/BasisOfPresentationDetails</Role>
      <ShortName>Basis of presentation (Details)</ShortName>
      <XmlFileName>R33.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2403403 - Disclosure - Basis of presentation (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/BasisOfPresentationDetails2</Role>
      <ShortName>Basis of presentation (Details 2)</ShortName>
      <XmlFileName>R34.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - Investments in real estate Schedule of investment in real estates (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsInRealEstateScheduleOfInvestmentInRealEstatesDetails</Role>
      <ShortName>Investments in real estate Schedule of investment in real estates (Details)</ShortName>
      <XmlFileName>R35.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2404403 - Disclosure - Investments in real estate Investment in Real Estates (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsInRealEstateInvestmentInRealEstatesDetails</Role>
      <ShortName>Investments in real estate Investment in Real Estates (Details)</ShortName>
      <XmlFileName>R36.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2404404 - Disclosure - Investments in real estate Real Estate Asset Sales (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsInRealEstateRealEstateAssetSalesDetails</Role>
      <ShortName>Investments in real estate Real Estate Asset Sales (Details)</ShortName>
      <XmlFileName>R37.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InvestmentsDetails</Role>
      <ShortName>Investments (Details)</ShortName>
      <XmlFileName>R38.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - Secured and unsecured senior debt Narratives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SecuredAndUnsecuredSeniorDebtNarrativesDetails</Role>
      <ShortName>Secured and unsecured senior debt Narratives (Details)</ShortName>
      <XmlFileName>R39.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2406403 - Disclosure - Secured and unsecured senior debt Schedule of secured and unsecured senior debts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SecuredAndUnsecuredSeniorDebtScheduleOfSecuredAndUnsecuredSeniorDebtsDetails</Role>
      <ShortName>Secured and unsecured senior debt Schedule of secured and unsecured senior debts (Details)</ShortName>
      <XmlFileName>R40.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2406404 - Disclosure - Secured and unsecured senior debt Outstanding consolidated indebtedness (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SecuredAndUnsecuredSeniorDebtOutstandingConsolidatedIndebtednessDetails</Role>
      <ShortName>Secured and unsecured senior debt Outstanding consolidated indebtedness (Details)</ShortName>
      <XmlFileName>R41.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2406405 - Disclosure - Secured and unsecured senior debt Interest Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SecuredAndUnsecuredSeniorDebtInterestExpenseDetails</Role>
      <ShortName>Secured and unsecured senior debt Interest Expense (Details)</ShortName>
      <XmlFileName>R42.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - Interest rate swap agreements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InterestRateSwapAgreementsDetails</Role>
      <ShortName>Interest rate swap agreements (Details)</ShortName>
      <XmlFileName>R43.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Interest rate swap agreements Outstanding interest rate swap (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/InterestRateSwapAgreementsOutstandingInterestRateSwapDetails</Role>
      <ShortName>Interest rate swap agreements Outstanding interest rate swap (Details)</ShortName>
      <XmlFileName>R44.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - Fair value measurements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/FairValueMeasurementsDetails</Role>
      <ShortName>Fair value measurements (Details)</ShortName>
      <XmlFileName>R45.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - Fair value measurements (Details 2)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/FairValueMeasurementsDetails2</Role>
      <ShortName>Fair value measurements (Details 2)</ShortName>
      <XmlFileName>R46.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - Earnings per share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/EarningsPerShareDetails</Role>
      <ShortName>Earnings per share (Details)</ShortName>
      <XmlFileName>R47.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - Net income attributable to Alexandria Real Estate Equities, Inc. (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/NetIncomeAttributableToAlexandriaRealEstateEquitiesIncDetails</Role>
      <ShortName>Net income attributable to Alexandria Real Estate Equities, Inc. (Details)</ShortName>
      <XmlFileName>R48.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2411402 - Disclosure - Stockholders' equity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/StockholdersEquityDetails</Role>
      <ShortName>Stockholders' equity (Details)</ShortName>
      <XmlFileName>R49.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2411403 - Disclosure - Stockholders' equity Schedule of Accumulated Other Comprehensive Income (Loss) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/StockholdersEquityScheduleOfAccumulatedOtherComprehensiveIncomeLossDetails</Role>
      <ShortName>Stockholders' equity Schedule of Accumulated Other Comprehensive Income (Loss) (Details)</ShortName>
      <XmlFileName>R50.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2412401 - Disclosure - Noncontrolling interests (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/NoncontrollingInterestsDetails</Role>
      <ShortName>Noncontrolling interests (Details)</ShortName>
      <XmlFileName>R51.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2414402 - Disclosure - Discontinued operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/DiscontinuedOperationsDetails</Role>
      <ShortName>Discontinued operations (Details)</ShortName>
      <XmlFileName>R52.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2415402 - Disclosure - Subsequent events Narratives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SubsequentEventsNarrativesDetails</Role>
      <ShortName>Subsequent events Narratives (Details)</ShortName>
      <XmlFileName>R53.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2415403 - Disclosure - Subsequent events Schedule of Long-term Debt Financing (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/SubsequentEventsScheduleOfLongTermDebtFinancingDetails</Role>
      <ShortName>Subsequent events Schedule of Long-term Debt Financing (Details)</ShortName>
      <XmlFileName>R54.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - Condensed consolidating financial information Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/CondensedConsolidatingFinancialInformationBalanceSheetDetails</Role>
      <ShortName>Condensed consolidating financial information Balance Sheet (Details)</ShortName>
      <XmlFileName>R55.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2416403 - Disclosure - Condensed consolidating financial information Income Statement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/CondensedConsolidatingFinancialInformationIncomeStatementDetails</Role>
      <ShortName>Condensed consolidating financial information Income Statement (Details)</ShortName>
      <XmlFileName>R56.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2416404 - Disclosure - Condensed consolidating financial information Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/CondensedConsolidatingFinancialInformationComprehensiveIncomeDetails</Role>
      <ShortName>Condensed consolidating financial information Comprehensive Income (Details)</ShortName>
      <XmlFileName>R57.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2416405 - Disclosure - Condensed consolidating financial information Cash Flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.are.com/role/CondensedConsolidatingFinancialInformationCashFlowsDetails</Role>
      <ShortName>Condensed consolidating financial information Cash Flows (Details)</ShortName>
      <XmlFileName>R58.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Element us-gaap_AreaOfRealEstateProperty had a mix of decimals attribute values: -5 -3 0.</Log>
    <Log type="Info">Element us-gaap_GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes had a mix of decimals attribute values: -3 0.</Log>
    <Log type="Info">Element us-gaap_InterestRateCashFlowHedgeLiabilityAtFairValue had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">'Monetary' elements on report '2409402 - Disclosure - Earnings per share (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '2411402 - Disclosure - Stockholders' equity (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '2415402 - Disclosure - Subsequent events Narratives (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '2416403 - Disclosure - Condensed consolidating financial information Income Statement (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '2416405 - Disclosure - Condensed consolidating financial information Cash Flows (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 1001000 - Statement - Consolidated Balance Sheets (Unaudited)</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Jun. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2011'</Log>
    <Log type="Info">Process Flow-Through: 1002000 - Statement - Consolidated Statements of Income (Unaudited)</Log>
    <Log type="Info">Process Flow-Through: 1003000 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</Log>
    <Log type="Info">Process Flow-Through: 1005000 - Statement - Consolidated Statements of Cash Flows (Unaudited)</Log>
  </Logs>
  <InputFiles>
    <File>are-20130630.xml</File>
    <File>are-20130630.xsd</File>
    <File>are-20130630_cal.xml</File>
    <File>are-20130630_def.xml</File>
    <File>are-20130630_lab.xml</File>
    <File>are-20130630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
