2.4.0.82404402 - Disclosure - Investments in real estate Schedule of investment in real estates (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$I2013Q2http://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00TransactionStandardhttp://www.are.com/20130630Transactionare0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$I2012Q4http://www.sec.gov/CIK0001035443instant2012-12-31T00:00:000001-01-01T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 2us-gaap_RealEstateInvestmentsAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investments in real estate2false 3us-gaap_Landus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse512915000512915USD$falsetruefalse2truefalsefalse522664000522664USD$falsetruefalsexbrli:monetaryItemTypemonetaryCarrying amount as of the balance sheet date of real estate held for productive use. This excludes land held for sale.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 4 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=6361293&loc=d3e6812-107765 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.13) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false2Land (related to rental properties)3false 3us-gaap_InvestmentBuildingAndBuildingImprovementsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse50069870005006987USD$falsefalsefalse2truefalsefalse49333140004933314USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Buildings and building improvements4false 3are_ImprovementsOthersare_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse166894000166894USD$falsefalsefalse2truefalsefalse189793000189793USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount as of the balance sheet date of improvements not otherwise specified in the existing taxonomy.No definition available.false2Other improvements5false 3us-gaap_RentalPropertiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse56867960005686796USD$falsefalsefalse2truefalsefalse56457710005645771USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount of income producing properties held for rental.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 true2Rental properties6false 3us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciationus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-878199000-878199USD$falsefalsefalse2truefalsefalse-875035000-875035USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe cumulative amount of depreciation for real estate property held for investment purposes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(3)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 7 false2Less: accumulated depreciation7false 3are_RentalPropertiesNetare_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse48085970004808597USD$falsefalsefalse2truefalsefalse47707360004770736USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe net book value of rental properties.No definition available.true2Rental properties, net8true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:9false 6us-gaap_RealEstateInvestmentPropertyNetus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse64533790006453379USD$falsefalsefalse2truefalsefalse64245780006424578USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Investments in real estate, net10false 6are_NumberOfRealEstatePropertyConstructionOrPreconstructionActivitiesare_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:integerItemTypeintegerThe number of the construction or preconstruction activities.No definition available.false256Number of projects undergoing construction11false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3false truefalseI2013Q2_us-gaap_StatementGeographicalAxis_are_NorthAmericaMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseNorth America [Member]us-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldiare_NorthAmericaMemberus-gaap_StatementGeographicalAxisexplicitMembersqftStandardhttp://www.xbrl.org/2009/utrsqftutreg0nanafalse0North America [Member]12true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:13false 6are_AreaofRealEstatePropertyDevelopmentandExpansionRightsExistingRentalPropertiesare_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse715000715000falsefalsefalse2falsefalsefalse00falsefalsefalsenum:areaItemTypedecimalArea of Real Estate Property, Development and Expansion Rights, Existing Rental PropertiesNo definition available.false256Area of real estate development and expansion rights to current rental properties (square foot)14false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse4false truefalseI2013Q2_us-gaap_StatementGeographicalAxis_are_NewYorkCityMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseNew York Cityus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldiare_NewYorkCityMemberus-gaap_StatementGeographicalAxisexplicitMembersqftStandardhttp://www.xbrl.org/2009/utrsqftutreg0nanafalse0New York City15true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:16false 6are_AreaofRealEstatePropertyFutureGroundupDevelopmentare_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse420000420000falsefalsefalse2falsefalsefalse00falsefalsefalsenum:areaItemTypedecimalArea of Real Estate Property, Future Ground-up DevelopmentNo definition available.false256Area of real estate for future ground-up development (square foot)17false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse5false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_ConstructionInProgressAndCurrentValueAddedProjectsMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseConstruction in progress ("CIP")/current value-added projects:us-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_ConstructionInProgressAndCurrentValueAddedProjectsMemberus-gaap_RealEstatePropertiesAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Construction in progress ("CIP")/current value-added projects:18true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:19false 6us-gaap_DevelopmentInProcessus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse964575000964575USD$falsefalsefalse2truefalsefalse842179000842179USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe current amount of expenditures for a real estate project that has not yet been completed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.10) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Development in process20false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse7false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_ActiveDevelopmentMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseActive development in North Americaus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_ActiveDevelopmentMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseNorth Americaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberus-gaap_StatementGeographicalAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Active development in North America | North America21true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:22false 6us-gaap_DevelopmentInProcessus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse673461000673461USD$falsefalsefalse2truefalsefalse431578000431578USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe current amount of expenditures for a real estate project that has not yet been completed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.10) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Development in process23false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse9false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_us-gaap_RealEstateInvestmentMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseInvestment in unconsolidated joint ventureus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RealEstateInvestmentMemberus-gaap_RealEstatePropertiesAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Investment in unconsolidated joint venture24true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:25false 6us-gaap_DevelopmentInProcessus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse3383800033838USD$falsefalsefalse2truefalsefalse2865600028656USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe current amount of expenditures for a real estate project that has not yet been completed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.10) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Development in process26false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse11false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_ActiveRedevelopmentMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseActive redevelopment in North Americaus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_ActiveRedevelopmentMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseNorth Americaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberus-gaap_StatementGeographicalAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Active redevelopment in North America | North America27true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:28false 6us-gaap_DevelopmentInProcessus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse104994000104994USD$falsefalsefalse2truefalsefalse199744000199744USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe current amount of expenditures for a real estate project that has not yet been completed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.10) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Development in process29false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse13false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_ActiveDevelopmentAndRedevelopmentMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupTwoMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseActive development and redevelopment in Asiaus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_ActiveDevelopmentAndRedevelopmentMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseAsiaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupTwoMemberus-gaap_StatementGeographicalAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Active development and redevelopment in Asia | Asia30true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:31false 6us-gaap_DevelopmentInProcessus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse9894900098949USD$falsefalsefalse2truefalsefalse101602000101602USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe current amount of expenditures for a real estate project that has not yet been completed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.10) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Development in process32false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse15false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_GenericInfrastructureAndBuildingImprovementProjectsMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseGeneric infrastructure/building improvement projects in North Americaus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_GenericInfrastructureAndBuildingImprovementProjectsMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseNorth Americaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberus-gaap_StatementGeographicalAxisexplicitMembernumberStandardhttp://www.xbrl.org/2003/instancepurexbrli0sqftStandardhttp://www.xbrl.org/2009/utrsqftutreg0PropertyStandardhttp://www.are.com/20130630propertyare0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Generic infrastructure/building improvement projects in North America | North America33true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:34false 6us-gaap_DevelopmentInProcessus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse5333300053333[1]USD$falsefalsefalse2truefalsefalse8059900080599USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe current amount of expenditures for a real estate project that has not yet been completed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.10) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Development in process35false 6us-gaap_AreaOfRealEstatePropertyus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse9637296372falsefalsefalse2falsefalsefalse00falsefalsefalsenum:areaItemTypedecimalArea of a real estate property.No definition available.false256Area of office property (square foot)36false 6are_NumberOfRealEstatePropertyConstructionOrPreconstructionActivitiesare_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse44falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:integerItemTypeintegerThe number of the construction or preconstruction activities.No definition available.false256Number of projects undergoing construction37false 6are_RealEstatePropertyOccupancyRateare_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.810.81falsefalsefalse2falsefalsefalse00falsefalsefalsenum:percentItemTypepureReal Estate Property, Occupancy RateNo definition available.false0Percent of total RSF (in percent)38false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse17false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_LandAndFutureValueAddedProjectsMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseLand/future value-added projects:us-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_LandAndFutureValueAddedProjectsMemberus-gaap_RealEstatePropertiesAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Land/future value-added projects:39true 5are_LandAndFutureValueAddedProjectsAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Land/future value-added projects:40false 6us-gaap_LandAvailableForDevelopmentus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse680207000680207USD$falsefalsefalse2truefalsefalse811663000811663USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount of land available for development.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph d -Article 7 false2Land available for development41false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse19false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_LandUndergoingPreconstructionActivitiesMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseLand undergoing predevelopment activities (CIP) in North America (2)us-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_LandUndergoingPreconstructionActivitiesMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseNorth Americaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberus-gaap_StatementGeographicalAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Land undergoing predevelopment activities (CIP) in North America (2) | North America42true 5are_LandAndFutureValueAddedProjectsAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Land/future value-added projects:43false 6us-gaap_LandAvailableForDevelopmentus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse313498000313498[2]USD$falsefalsefalse2truefalsefalse433310000433310[2]USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount of land available for development.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph d -Article 7 false2Land available for development44false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse21false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_LandHeldForFutureDevelopmentMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseLand held for future development in North Americaus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_LandHeldForFutureDevelopmentMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseNorth Americaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMemberus-gaap_StatementGeographicalAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Land held for future development in North America | North America45true 5are_LandAndFutureValueAddedProjectsAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Land/future value-added projects:46false 6us-gaap_LandAvailableForDevelopmentus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse211292000211292USD$falsefalsefalse2truefalsefalse296039000296039USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount of land available for development.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph d -Article 7 false2Land available for development47false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse23false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_LandHeldForFutureDevelopmentAndLandUndergoingPreconstructionActivitiesMember_us-gaap_StatementGeographicalAxis_us-gaap_SegmentGeographicalGroupsOfCountriesGroupTwoMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseLand held for future development/undergoing predevelopment activities (CIP) in Asiaus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_LandHeldForFutureDevelopmentAndLandUndergoingPreconstructionActivitiesMemberus-gaap_RealEstatePropertiesAxisexplicitMemberfalsefalseAsiaus-gaap_StatementGeographicalAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SegmentGeographicalGroupsOfCountriesGroupTwoMemberus-gaap_StatementGeographicalAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Land held for future development/undergoing predevelopment activities (CIP) in Asia | Asia48true 5are_LandAndFutureValueAddedProjectsAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Land/future value-added projects:49false 6us-gaap_LandAvailableForDevelopmentus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse7910500079105USD$falsefalsefalse2truefalsefalse8231400082314USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount of land available for development.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph d -Article 7 false2Land available for development50false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse25false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_LandSubjectToSaleNegotiationMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseLand subject to sale negotiationsus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_LandSubjectToSaleNegotiationMemberus-gaap_RealEstatePropertiesAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Land subject to sale negotiations51true 5are_LandAndFutureValueAddedProjectsAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Land/future value-added projects:52false 6us-gaap_LandAvailableForDevelopmentus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse7631200076312USD$falsefalsefalse2falsefalsefalse00  USD$falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying amount of land available for development.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph d -Article 7 false2Land available for development53false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse27false USDtruefalse$I2013Q2_us-gaap_RealEstatePropertiesAxis_are_RentalPropertiesNetAndConstructionInProgressAndCurrentValueAddedProjectsMemberhttp://www.sec.gov/CIK0001035443instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseRental properties, net and Construction in progress ("CIP")/current value-added projectsus-gaap_RealEstatePropertiesAxisxbrldihttp://xbrl.org/2006/xbrldiare_RentalPropertiesNetAndConstructionInProgressAndCurrentValueAddedProjectsMemberus-gaap_RealEstatePropertiesAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Rental properties, net and Construction in progress ("CIP")/current value-added projects54true 5are_DevelopmentInProcessAbstractare_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Construction in progress ("CIP")/current value-added projects:55false 6us-gaap_RealEstateInvestmentPropertyNetus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse57731720005773172USD$falsetruefalse2truefalsefalse56129150005612915USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 false2Investments in real estate, net1Represents the book value associated with approximately 96,372 square feet at four projects undergoing construction of generic laboratory improvements, of which approximately 81% was leased, but not delivered, as of June 30, 2013.2In addition to assets included in our gross investment in real estate, we hold options/rights for parcels supporting the future ground-up development of approximately 420,000 RSF in Alexandria CenterTM for Life Science - New York City related to an option under our ground lease. Also, our asset base contains additional embedded development opportunities aggregating approximately 715,000 RSF which represents additional development and expansion rights related to existing rental properties.falseInvestments in real estate Schedule of investment in real estates (Details) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.are.com/role/InvestmentsInRealEstateScheduleOfInvestmentInRealEstatesDetails255