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Investments in Unconsolidated Joint Ventures - Narrative (Details) (USD $)
 3 Months Ended 12 Months Ended
Dec. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jun. 30, 2014
investment
Schedule of Equity Method Investments [Line Items]          
Gain (Loss) on Sale of Properties $ 43,200,000us-gaap_GainLossOnSaleOfProperties $ 91,661,000us-gaap_GainLossOnSaleOfProperties $ 98,403,000us-gaap_GainLossOnSaleOfProperties $ 12,426,000us-gaap_GainLossOnSaleOfProperties  
Company's net investment in unconsolidated joint ventures 208,832,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures 208,832,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures 179,655,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures    
Impairment of Real Estate   100,000us-gaap_ImpairmentOfRealEstate 900,000us-gaap_ImpairmentOfRealEstate 2,300,000us-gaap_ImpairmentOfRealEstate  
Development in Process 277,411,000us-gaap_DevelopmentInProcess 277,411,000us-gaap_DevelopmentInProcess 209,187,000us-gaap_DevelopmentInProcess    
Liberty Venture I, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Company's net investment in unconsolidated joint ventures 20,010,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyVentureILpMember		 [1] 20,010,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyVentureILpMember		 [1] 8,551,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyVentureILpMember		 [1]    
Development in Process 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyVentureILpMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyVentureILpMember		 2,226,000us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyVentureILpMember		    
Kings Hill Unit Trust [Member]          
Schedule of Equity Method Investments [Line Items]          
Company's net investment in unconsolidated joint ventures 11,663,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember		 [1] 11,663,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember		 [1] 12,772,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember		 [1]    
Development in Process 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember		    
Liberty Illinois, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Company's net investment in unconsolidated joint ventures 18,692,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember		 [1] 18,692,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember		 [1] 21,688,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember		 [1]    
Development in Process 17,973,000us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember		 17,973,000us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember		    
Liberty Washington, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Company's net investment in unconsolidated joint ventures 69,230,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyWashingtonLpMember		 [1] 69,230,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyWashingtonLpMember		 [1] 72,981,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyWashingtonLpMember		 [1]    
Development in Process 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyWashingtonLpMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyWashingtonLpMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyWashingtonLpMember		    
Liberty Commerz 1701 JFK Boulevard, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Company's net investment in unconsolidated joint ventures 23,153,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember		 [1] 23,153,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember		 [1] 24,740,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember		 [1]    
Development in Process 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember		 0us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember		    
Comcast Innovation and Technology Center [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of equity method investments         2lry_Numberofequitymethodinvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember
Ownership Percentage 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Anticipated aggregate investment 921,000,000lry_AnticipatedAggregateInvestment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 921,000,000lry_AnticipatedAggregateInvestment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Anticipated investment in joint ventures 184,000,000lry_Anticipatedinvestmentinjointventures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 184,000,000lry_Anticipatedinvestmentinjointventures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Company's net investment in unconsolidated joint ventures 21,300,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 21,300,000us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Number of stories in a high-rise building 59lry_Numberofstoriesinahighrisebuilding
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= lry_ComcastInnovationandTechnologyCenterMember		 59lry_Numberofstoriesinahighrisebuilding
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Net Rentable Area 1,300,000us-gaap_NetRentableArea
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 1,300,000us-gaap_NetRentableArea
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= lry_ComcastInnovationandTechnologyCenterMember		      
Number of hotel rooms 222lry_Numberofhotelrooms
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 222lry_Numberofhotelrooms
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Development in Process 111,200,000us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		 111,200,000us-gaap_DevelopmentInProcess
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_ComcastInnovationandTechnologyCenterMember		      
Cambridge Medipark Ltd [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of Real Estate Properties 0us-gaap_NumberOfRealEstateProperties
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= lry_CambridgeMediparkLtdMember		 0us-gaap_NumberOfRealEstateProperties
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= lry_CambridgeMediparkLtdMember		      
United Kingdom [Member] | Kings Hill Unit Trust [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
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= lry_KingsHillUnitTrustMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		      
Square Footage of Real Estate Property 490,000us-gaap_AreaOfRealEstateProperty
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= lry_KingsHillUnitTrustMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		 490,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_KingsHillUnitTrustMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		      
United Kingdom [Member] | Blythe Valley JV Sarl [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage       20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
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= lry_BlytheValleyJvSarlMember
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= lry_UnitedKingdomMember		  
Company's net investment in unconsolidated joint ventures 0us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
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= lry_BlytheValleyJvSarlMember
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= lry_UnitedKingdomMember		 0us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
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= lry_BlytheValleyJvSarlMember
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= lry_UnitedKingdomMember		   0us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
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= lry_BlytheValleyJvSarlMember
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= lry_UnitedKingdomMember		  
Impairment of Real Estate, Attributable to Parent       4,600,000lry_ImpairmentOfRealEstateAttributableToParent
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_BlytheValleyJvSarlMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		  
United Kingdom [Member] | Silversword Properties Ltd [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_SilverswordPropertiesLtdMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
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= lry_SilverswordPropertiesLtdMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		      
United Kingdom [Member] | Cambridge Medipark Ltd [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_CambridgeMediparkLtdMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_CambridgeMediparkLtdMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		      
Chicago Milwaukee [Member] | Liberty Illinois, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 25.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		 25.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Square Footage of Real Estate Property 5,100,000us-gaap_AreaOfRealEstateProperty
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= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		 5,100,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Acres of Developable Land 248lry_AcresOfDevelopableLand
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		 248lry_AcresOfDevelopableLand
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Other Segments [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of Real Estate Properties 1us-gaap_NumberOfRealEstateProperties
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember		 1us-gaap_NumberOfRealEstateProperties
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember		      
Square Footage of Real Estate Property 83,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember		 83,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember		      
Other Segments [Member] | Liberty AIPO, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyAipoLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember		 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyAipoLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember		      
Philadelphia [Member] | Liberty Commerz 1701 JFK Boulevard, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember
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= lry_PhiladelphiaMember		 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
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= lry_LibertyCommerz1701JfkBoulevardLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		      
Number of Real Estate Properties 1us-gaap_NumberOfRealEstateProperties
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		 1us-gaap_NumberOfRealEstateProperties
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= lry_LibertyCommerz1701JfkBoulevardLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		      
Square Footage of Real Estate Property 1,250,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyCommerz1701JfkBoulevardLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		 1,250,000us-gaap_AreaOfRealEstateProperty
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= lry_LibertyCommerz1701JfkBoulevardLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		      
Philadelphia [Member] | Liberty Property 19th & Arch LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Ownership Percentage 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyProperty19thArchLPMember
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= lry_PhiladelphiaMember		 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyProperty19thArchLPMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		      
Acres of Developable Land 1lry_AcresOfDevelopableLand
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyProperty19thArchLPMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		 1lry_AcresOfDevelopableLand
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= lry_LibertyProperty19thArchLPMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_PhiladelphiaMember		      
Construction in Progress [Member] | Chicago Milwaukee [Member] | Liberty Illinois, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Square Footage of Real Estate Property 430,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_RealEstatePropertiesAxis
= us-gaap_ConstructionInProgressMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		 430,000us-gaap_AreaOfRealEstateProperty
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= us-gaap_ConstructionInProgressMember
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= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Anticipated aggregate investment 24,400,000lry_AnticipatedAggregateInvestment
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= us-gaap_ConstructionInProgressMember
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= lry_LibertyIllinoisLpMember
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= lry_ChicagoMilwaukeeMember		 24,400,000lry_AnticipatedAggregateInvestment
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= us-gaap_ConstructionInProgressMember
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= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Industrial Property [Member] | United Kingdom [Member] | Kings Hill Unit Trust [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of Real Estate Properties 3us-gaap_NumberOfRealEstateProperties
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
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= lry_KingsHillUnitTrustMember
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= lry_UnitedKingdomMember		 3us-gaap_NumberOfRealEstateProperties
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= us-gaap_IndustrialPropertyMember
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= lry_KingsHillUnitTrustMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_UnitedKingdomMember		      
Industrial Property [Member] | Chicago Milwaukee [Member] | Liberty Illinois, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of Real Estate Properties 15us-gaap_NumberOfRealEstateProperties
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		 15us-gaap_NumberOfRealEstateProperties
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Industrial Property [Member] | Construction in Progress [Member] | Chicago Milwaukee [Member] | Liberty Illinois, LP [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of Real Estate Properties 1us-gaap_NumberOfRealEstateProperties
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
/ us-gaap_RealEstatePropertiesAxis
= us-gaap_ConstructionInProgressMember
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= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		 1us-gaap_NumberOfRealEstateProperties
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
/ us-gaap_RealEstatePropertiesAxis
= us-gaap_ConstructionInProgressMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lry_LibertyIllinoisLpMember
/ us-gaap_StatementBusinessSegmentsAxis
= lry_ChicagoMilwaukeeMember		      
Office Building [Member] | United Kingdom [Member] | Kings Hill Unit Trust [Member]          
Schedule of Equity Method Investments [Line Items]          
Number of Real Estate Properties 11us-gaap_NumberOfRealEstateProperties
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[1] Differences between the Company's net investment in unconsolidated joint ventures and its underlying equity in the net assets of the venture are primarily a result of impairments related to the Company's investment in unconsolidated joint ventures, the deferral of gains associated with the sales of properties to joint ventures in which the Company retains an ownership interest and loans made to the joint ventures by the Company. These adjustments have resulted in an aggregate difference increasing the Company's investments in unconsolidated joint ventures by $3.2 million as of December 31, 2014 and reducing the Company's investment in unconsolidated joint ventures by $41.7 million as of December 31, 2013. Differences between historical cost basis and the basis reflected at the joint venture level (other than loans) are typically depreciated over the life of the related asset.