Annual report pursuant to Section 13 and 15(d)

Schedule III (Details)

v2.4.1.9
Schedule III (Details) (USD $)
12 Months Ended
Dec. 31, 2014
sqft
units
Dec. 31, 2013
sqft
Dec. 31, 2012
sqft
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land $ 569,407,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand [1]    
Initial Cost, Buildings and Improvements 1,347,370,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements [1]    
Net Improvements (Retirement) since Acquisition 630,411,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements    
Gross Amounts at Which Carried at December 31, 2011, Land 543,546,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 2,003,642,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements    
Gross Amounts at Which Carried at December 31, 2011, Total 2,547,188,000us-gaap_RealEstateGrossAtCarryingValue [2] 2,289,509,000us-gaap_RealEstateGrossAtCarryingValue 2,529,131,000us-gaap_RealEstateGrossAtCarryingValue
Accumulated Depreciation at December 31, 2011 640,434,000us-gaap_RealEstateAccumulatedDepreciation 611,408,000us-gaap_RealEstateAccumulatedDepreciation 610,536,000us-gaap_RealEstateAccumulatedDepreciation
Net Rentable Square Feet 9,971,000wre_NetRentableSquareFeet [3]    
Units 3,053us-gaap_NumberOfUnitsInRealEstateProperty    
Real estate, federal income tax basis 2,113,200,000us-gaap_RealEstateFederalIncomeTaxBasis    
Area of land 430,000us-gaap_AreaOfRealEstateProperty 1,172,000us-gaap_AreaOfRealEstateProperty 134,000us-gaap_AreaOfRealEstateProperty
Development in Process 76,235,000us-gaap_DevelopmentInProcess 61,315,000us-gaap_DevelopmentInProcess  
Secured Debt 418,525,000us-gaap_SecuredDebt 294,671,000us-gaap_SecuredDebt  
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, beginning of period 2,289,509,000us-gaap_RealEstateGrossAtCarryingValue 2,529,131,000us-gaap_RealEstateGrossAtCarryingValue 2,449,872,000us-gaap_RealEstateGrossAtCarryingValue
Property acquisitions 289,140,000us-gaap_RealEstateOtherAcquisitions [4] 47,444,000us-gaap_RealEstateOtherAcquisitions [4] 47,772,000us-gaap_RealEstateOtherAcquisitions [4]
Improvements 98,250,000us-gaap_RealEstateImprovements [4] 71,127,000us-gaap_RealEstateImprovements [4] 59,664,000us-gaap_RealEstateImprovements [4]
Impairment write-down 0wre_ImpairmentGrossAsset 0wre_ImpairmentGrossAsset (2,097,000)wre_ImpairmentGrossAsset
Write-off of disposed assets (2,857,000)wre_WriteDownOfRealEstateDisposedOf (2,017,000)wre_WriteDownOfRealEstateDisposedOf (1,450,000)wre_WriteDownOfRealEstateDisposedOf
Property sales (126,854,000)us-gaap_RealEstateCostOfRealEstateSold (356,176,000)us-gaap_RealEstateCostOfRealEstateSold (24,630,000)us-gaap_RealEstateCostOfRealEstateSold
Balance, end of period 2,547,188,000us-gaap_RealEstateGrossAtCarryingValue [2] 2,289,509,000us-gaap_RealEstateGrossAtCarryingValue 2,529,131,000us-gaap_RealEstateGrossAtCarryingValue
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, beginning of period 611,408,000us-gaap_RealEstateAccumulatedDepreciation 610,536,000us-gaap_RealEstateAccumulatedDepreciation 535,732,000us-gaap_RealEstateAccumulatedDepreciation
Depreciation 77,741,000us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense 80,510,000us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense 84,949,000us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense
Impairment write-down 0us-gaap_RealEstateAccumulatedDepreciationOtherDeductions 0us-gaap_RealEstateAccumulatedDepreciationOtherDeductions 0us-gaap_RealEstateAccumulatedDepreciationOtherDeductions
Write-off of disposed assets (2,549,000)wre_RealEstateAccumulatedDepreciationWriteOffOfDisposedAssets (1,404,000)wre_RealEstateAccumulatedDepreciationWriteOffOfDisposedAssets (1,124,000)wre_RealEstateAccumulatedDepreciationWriteOffOfDisposedAssets
Property sales (46,166,000)us-gaap_RealEstateAccumulatedDepreciationRealEstateSold (78,234,000)us-gaap_RealEstateAccumulatedDepreciationRealEstateSold (9,021,000)us-gaap_RealEstateAccumulatedDepreciationRealEstateSold
Balance, end of period 640,434,000us-gaap_RealEstateAccumulatedDepreciation 611,408,000us-gaap_RealEstateAccumulatedDepreciation 610,536,000us-gaap_RealEstateAccumulatedDepreciation
Multifamily Properties [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 94,208,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
[1]    
Initial Cost, Buildings and Improvements 186,344,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
[1]    
Net Improvements (Retirement) since Acquisition 263,988,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 82,569,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 461,971,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 544,540,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
[2]    
Accumulated Depreciation at December 31, 2011 147,942,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
   
Net Rentable Square Feet 2,594,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
[3]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 544,540,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 147,942,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MultifamilyPropertiesMember
   
3801 Connecticut [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 420,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[1],[5]    
Initial Cost, Buildings and Improvements 2,678,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 10,698,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 420,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 13,376,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 13,796,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 9,339,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[5]    
Year of Construction Jan. 01, 1951 [5]    
Date of Acquisition Jan. 01, 1963 [5]    
Net Rentable Square Feet 179,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[3]    
Units 307us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
   
Depreciation Life 30 years [6]    
Secured Debt 35,400,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 13,796,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 9,339,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A3801ConnecticutMember
[5]    
Roosevelt Towers [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 336,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
[1]    
Initial Cost, Buildings and Improvements 1,996,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
[1]    
Net Improvements (Retirement) since Acquisition 11,148,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 336,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 13,144,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 13,480,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
[2]    
Accumulated Depreciation at December 31, 2011 8,296,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
   
Year of Construction Jan. 01, 1964    
Date of Acquisition May 01, 1965    
Net Rentable Square Feet 170,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
[3]    
Units 191us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
   
Depreciation Life 40 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 13,480,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 8,296,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RooseveltTowersMember
   
Country Club Towers [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 299,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
[1]    
Initial Cost, Buildings and Improvements 2,562,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
[1]    
Net Improvements (Retirement) since Acquisition 15,144,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 299,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 17,706,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 18,005,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
[2]    
Accumulated Depreciation at December 31, 2011 11,055,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
   
Year of Construction Jan. 01, 1965    
Date of Acquisition Jul. 01, 1969    
Net Rentable Square Feet 159,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
[3]    
Units 227us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
   
Depreciation Life 35 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 18,005,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 11,055,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CountryClubTowersMember
   
Park Adams [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 287,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
[1]    
Initial Cost, Buildings and Improvements 1,654,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
[1]    
Net Improvements (Retirement) since Acquisition 10,227,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 287,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,881,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 12,168,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
[2]    
Accumulated Depreciation at December 31, 2011 8,361,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
   
Year of Construction Jan. 01, 1959    
Date of Acquisition Jan. 01, 1969    
Net Rentable Square Feet 173,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
[3]    
Units 200us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
   
Depreciation Life 35 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 12,168,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 8,361,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ParkAdamsMember
   
Munson Hill Towers [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 322,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
[1]    
Initial Cost, Buildings and Improvements 3,337,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
[1]    
Net Improvements (Retirement) since Acquisition 15,739,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 322,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 19,076,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 19,398,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
[2]    
Accumulated Depreciation at December 31, 2011 14,111,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
   
Year of Construction Jan. 01, 1963    
Date of Acquisition Jan. 01, 1970    
Net Rentable Square Feet 258,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
[3]    
Units 279us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
   
Depreciation Life 33 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 19,398,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 14,111,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MunsonHillTowersMember
   
The Ashby at McLean [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,356,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
[1]    
Initial Cost, Buildings and Improvements 17,102,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
[1]    
Net Improvements (Retirement) since Acquisition 17,300,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,356,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 34,402,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 38,758,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
[2]    
Accumulated Depreciation at December 31, 2011 20,788,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
   
Year of Construction Jan. 01, 1982    
Date of Acquisition Aug. 01, 1996    
Net Rentable Square Feet 274,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
[3]    
Units 256us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 38,758,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 20,788,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_AshbyAtMcleanMember
   
Walker House Apartments [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 2,851,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[1],[5]    
Initial Cost, Buildings and Improvements 7,946,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 6,906,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 2,851,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 14,852,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 17,703,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 9,651,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[5]    
Year of Construction Jan. 01, 1971 [5]    
Date of Acquisition Mar. 01, 1996 [5]    
Net Rentable Square Feet 157,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[3]    
Units 212us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
   
Depreciation Life 30 years [6]    
Secured Debt 16,500,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 17,703,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 9,651,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WalkerHouseApartmentsMember
[5]    
Bethesda Hill Apartments [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 3,900,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[1],[5]    
Initial Cost, Buildings and Improvements 13,412,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 12,394,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 3,900,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,806,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 29,706,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 15,904,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[5]    
Year of Construction Jan. 01, 1986 [5]    
Date of Acquisition Nov. 01, 1997 [5]    
Net Rentable Square Feet 225,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[3],[5]    
Units 195us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
   
Depreciation Life 30 years [6]    
Secured Debt 29,100,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 29,706,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 15,904,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BethesdaHillApartmentsMember
[5]    
Bennett Park [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,861,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
[1]    
Initial Cost, Buildings and Improvements 917,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
[1]    
Net Improvements (Retirement) since Acquisition 79,610,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,774,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 78,614,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 83,388,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
[2]    
Accumulated Depreciation at December 31, 2011 26,172,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
   
Year of Construction Jan. 01, 2007    
Date of Acquisition Feb. 01, 2001    
Net Rentable Square Feet 214,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
[3]    
Units 224us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
   
Depreciation Life 28 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 83,388,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 26,172,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BennettParkMember
   
The Clayborne [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 269,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
[1]    
Initial Cost, Buildings and Improvements 0us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
[1]    
Net Improvements (Retirement) since Acquisition 30,631,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 699,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 30,201,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 30,900,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
[2]    
Accumulated Depreciation at December 31, 2011 11,428,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
   
Year of Construction Jan. 01, 2008    
Date of Acquisition Jun. 01, 2003    
Net Rentable Square Feet 60,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
[3]    
Units 74us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
   
Depreciation Life 26 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 30,900,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 11,428,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ClayborneMember
   
The Kenmore [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 28,222,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[1],[5]    
Initial Cost, Buildings and Improvements 33,955,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 10,296,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 28,222,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 44,251,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 72,473,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 8,765,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[5]    
Year of Construction Jan. 01, 1948 [5]    
Date of Acquisition Sep. 01, 2008 [5]    
Net Rentable Square Feet 268,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[3]    
Units 374us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 72,473,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 8,765,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreMember
[5]    
Six Fifty North Glebe Road [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [7]    
Initial Cost, Land 12,787,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[1],[7]    
Initial Cost, Buildings and Improvements 0us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[1],[7]    
Net Improvements (Retirement) since Acquisition 36,443,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[7]    
Gross Amounts at Which Carried at December 31, 2011, Land 12,851,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[7]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 36,379,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[7]    
Gross Amounts at Which Carried at December 31, 2011, Total 49,230,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[2],[7]    
Accumulated Depreciation at December 31, 2011 0us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[7]    
Year of Construction Jan. 01, 2014 [5]    
Date of Acquisition Jun. 01, 2011 [7]    
Net Rentable Square Feet 143,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[3]    
Units 163us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
   
Depreciation Life 30 years [6]    
Development in Process 17,900,000us-gaap_DevelopmentInProcess
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
   
Secured Debt 27,690,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
7,297,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[8],[9]  
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 49,230,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[2],[7]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 0us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SixFiftyNorthGlebeRoadMember
[7]    
1219 First Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [7]    
Initial Cost, Land 14,046,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[1],[7]    
Initial Cost, Buildings and Improvements 0us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[1],[7]    
Net Improvements (Retirement) since Acquisition 6,761,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[7]    
Gross Amounts at Which Carried at December 31, 2011, Land 0us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[7]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 20,807,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[7]    
Gross Amounts at Which Carried at December 31, 2011, Total 20,807,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[2],[7]    
Accumulated Depreciation at December 31, 2011 0us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[7]    
Date of Acquisition Nov. 01, 2011 [7]    
Net Rentable Square Feet 0wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
   
Units 0us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
   
Development in Process 20,800,000us-gaap_DevelopmentInProcess
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 20,807,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[2],[7]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 0us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1219FirstStreetMember
[7]    
The Paramount [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 8,568,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
[1]    
Initial Cost, Buildings and Improvements 38,716,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
[1]    
Net Improvements (Retirement) since Acquisition 670,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 8,568,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 39,386,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 47,954,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
[2]    
Accumulated Depreciation at December 31, 2011 2,118,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
   
Year of Construction Jan. 01, 1984    
Date of Acquisition Oct. 01, 2013 [5]    
Net Rentable Square Feet 141,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
[3]    
Units 135us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 47,954,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 2,118,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheParamountMember
   
Yale West [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 14,684,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[1],[5]    
Initial Cost, Buildings and Improvements 62,069,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 21,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 14,684,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 62,090,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 76,774,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 1,954,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[5]    
Year of Construction Jan. 01, 2011 [5]    
Date of Acquisition Feb. 01, 2014 [5]    
Net Rentable Square Feet 173,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[3],[5]    
Units 216us-gaap_NumberOfUnitsInRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
   
Depreciation Life 30 years [6]    
Secured Debt 53,029,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
0us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
 
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 76,774,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 1,954,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_YaleWestMember
[5]    
Office Buildings [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 342,605,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
[1]    
Initial Cost, Buildings and Improvements 902,423,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
[1]    
Net Improvements (Retirement) since Acquisition 293,403,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 328,089,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 1,210,342,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 1,538,431,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
[2]    
Accumulated Depreciation at December 31, 2011 384,682,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
   
Net Rentable Square Feet 4,853,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
[3]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 1,538,431,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 384,682,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OfficeBuildingsMember
   
1901 Pennsylvania Avenue [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 892,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
[1]    
Initial Cost, Buildings and Improvements 3,481,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
[1]    
Net Improvements (Retirement) since Acquisition 16,943,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 892,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 20,424,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 21,316,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
[2]    
Accumulated Depreciation at December 31, 2011 14,802,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
   
Year of Construction Jan. 01, 1960    
Date of Acquisition May 01, 1977    
Net Rentable Square Feet 101,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
   
Depreciation Life 28 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 21,316,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 14,802,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1901PennsylvaniaAvenueMember
   
51 Monroe Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 840,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
[1]    
Initial Cost, Buildings and Improvements 10,869,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 27,904,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 840,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 38,773,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 39,613,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 27,848,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
   
Year of Construction Jan. 01, 1975    
Date of Acquisition Aug. 01, 1979    
Net Rentable Square Feet 221,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
   
Depreciation Life 41 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 39,613,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 27,848,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A51MonroeStreetMember
   
515 King Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,102,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
[1]    
Initial Cost, Buildings and Improvements 3,931,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 5,744,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,102,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 9,675,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 13,777,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 5,164,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
   
Year of Construction Jan. 01, 1966    
Date of Acquisition Jul. 01, 1992    
Net Rentable Square Feet 75,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
   
Depreciation Life 50 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 13,777,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 5,164,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A515KingStreetMember
   
6110 Executive Boulevard [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 4,621,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
[1]    
Initial Cost, Buildings and Improvements 11,926,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
[1]    
Net Improvements (Retirement) since Acquisition 16,149,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,621,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 28,075,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 32,696,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
[2]    
Accumulated Depreciation at December 31, 2011 17,929,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
   
Year of Construction Jan. 01, 1971    
Date of Acquisition Jan. 01, 1995    
Net Rentable Square Feet 201,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 32,696,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 17,929,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A6110ExecutiveBoulevardMember
   
1220 19th Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 7,803,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
[1]    
Initial Cost, Buildings and Improvements 11,366,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 15,464,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 7,802,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 26,831,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 34,633,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 12,520,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
   
Year of Construction Jan. 01, 1976    
Date of Acquisition Nov. 01, 1995    
Net Rentable Square Feet 103,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 34,633,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 12,520,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122019ThStreetMember
   
1600 Wilson Boulevard [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 6,661,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
[1]    
Initial Cost, Buildings and Improvements 16,742,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
[1]    
Net Improvements (Retirement) since Acquisition 23,146,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 6,661,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 39,888,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 46,549,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
[2]    
Accumulated Depreciation at December 31, 2011 18,299,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
   
Year of Construction Jan. 01, 1973    
Date of Acquisition Oct. 01, 1997    
Net Rentable Square Feet 166,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 46,549,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 18,299,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1600WilsonBoulevardMember
   
7900 Westpark Drive [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [10]    
Initial Cost, Land 12,049,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[1],[10]    
Initial Cost, Buildings and Improvements 71,825,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[1]    
Net Improvements (Retirement) since Acquisition 68,237,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10]    
Gross Amounts at Which Carried at December 31, 2011, Land 12,049,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 140,062,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10]    
Gross Amounts at Which Carried at December 31, 2011, Total 152,111,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10],[2]    
Accumulated Depreciation at December 31, 2011 64,474,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10]    
Year of Construction Jan. 01, 1972    
Date of Acquisition Nov. 01, 1997    
Net Rentable Square Feet 526,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
   
Depreciation Life 30 years [6]    
Development in Process 26,100,000us-gaap_DevelopmentInProcess
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 152,111,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10],[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 64,474,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A7900WestparkDriveMember
[10]    
600 Jefferson Plaza [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 2,296,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
[1]    
Initial Cost, Buildings and Improvements 12,188,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
[1]    
Net Improvements (Retirement) since Acquisition 6,945,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 2,296,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 19,133,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 21,429,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
[2]    
Accumulated Depreciation at December 31, 2011 9,879,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
   
Year of Construction Jan. 01, 1985    
Date of Acquisition May 01, 1999    
Net Rentable Square Feet 113,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 21,429,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 9,879,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A600JeffersonPlazaMember
   
Wayne Plaza [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 1,564,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
[1]    
Initial Cost, Buildings and Improvements 6,243,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
[1]    
Net Improvements (Retirement) since Acquisition 9,049,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 1,564,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 15,292,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 16,856,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
[2]    
Accumulated Depreciation at December 31, 2011 7,976,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
   
Year of Construction Jan. 01, 1970    
Date of Acquisition May 01, 2000    
Net Rentable Square Feet 99,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 16,856,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 7,976,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WaynePlazaMember
   
Courthouse Square [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 0us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
[1]    
Initial Cost, Buildings and Improvements 17,096,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
[1]    
Net Improvements (Retirement) since Acquisition 7,946,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 0us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,042,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 25,042,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
[2]    
Accumulated Depreciation at December 31, 2011 11,976,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
   
Year of Construction Jan. 01, 1979    
Date of Acquisition Oct. 01, 2000    
Net Rentable Square Feet 116,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 25,042,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 11,976,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CourthouseSquareMember
   
One Central Plaza [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 5,480,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
[1]    
Initial Cost, Buildings and Improvements 39,107,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
[1]    
Net Improvements (Retirement) since Acquisition 17,721,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 5,480,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 56,828,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 62,308,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
[2]    
Accumulated Depreciation at December 31, 2011 28,510,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
   
Year of Construction Jan. 01, 1974    
Date of Acquisition Apr. 01, 2001    
Net Rentable Square Feet 267,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 62,308,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 28,510,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OneCentralPlazaMember
   
1776 G Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 31,500,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
[1]    
Initial Cost, Buildings and Improvements 54,327,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 5,217,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 31,500,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 59,544,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 91,044,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 25,560,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
   
Year of Construction Jan. 01, 1979    
Date of Acquisition Aug. 01, 2003    
Net Rentable Square Feet 263,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 91,044,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 25,560,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1776GStreetMember
   
Dulles Station II [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [10]    
Initial Cost, Land 15,001,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[1],[10]    
Initial Cost, Buildings and Improvements 494,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[1],[10]    
Net Improvements (Retirement) since Acquisition (3,400,000)us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10]    
Gross Amounts at Which Carried at December 31, 2011, Land 484,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,611,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10]    
Gross Amounts at Which Carried at December 31, 2011, Total 12,095,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10],[2]    
Accumulated Depreciation at December 31, 2011 403,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10]    
Date of Acquisition Dec. 01, 2005 [10]    
Net Rentable Square Feet 0wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
   
Area of land 360,000us-gaap_AreaOfRealEstateProperty
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
   
Land Placed In Service 3,600,000wre_LandPlacedInService
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
   
Development in Process 8,500,000us-gaap_DevelopmentInProcess
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 12,095,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10],[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 403,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_DullesStationIiMember
[10]    
West Gude Drive [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 11,580,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
[1]    
Initial Cost, Buildings and Improvements 43,240,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
[1]    
Net Improvements (Retirement) since Acquisition 11,699,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 11,580,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 54,939,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 66,519,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
[2]    
Accumulated Depreciation at December 31, 2011 17,686,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
   
Year of Construction Jan. 01, 1984    
Date of Acquisition Aug. 01, 2006    
Net Rentable Square Feet 276,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 66,519,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 17,686,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestGudeDriveMember
   
Monument II [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 10,244,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
[1]    
Initial Cost, Buildings and Improvements 65,205,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
[1]    
Net Improvements (Retirement) since Acquisition 7,075,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 10,244,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 72,280,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 82,524,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
[2]    
Accumulated Depreciation at December 31, 2011 19,424,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
   
Year of Construction Jan. 01, 2000    
Date of Acquisition Mar. 01, 2007    
Net Rentable Square Feet 208,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 82,524,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 19,424,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MonumentIiMember
   
2000 M Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 0us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
[1]    
Initial Cost, Buildings and Improvements 61,101,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 21,215,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 0us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 82,316,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 82,316,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 20,670,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
   
Year of Construction Jan. 01, 1971    
Date of Acquisition Dec. 01, 2007    
Net Rentable Square Feet 230,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 82,316,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 20,670,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A2000MStreetMember
   
M Street 2445 [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 46,887,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[1],[5]    
Initial Cost, Buildings and Improvements 106,743,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[1],[5]    
Net Improvements (Retirement) since Acquisition 5,127,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 46,887,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 111,870,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 158,757,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[2],[5]    
Accumulated Depreciation at December 31, 2011 26,905,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[5]    
Year of Construction Jan. 01, 1986    
Date of Acquisition Dec. 01, 2008    
Net Rentable Square Feet 290,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
   
Depreciation Life 30 years [6]    
Secured Debt 99,357,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[8] 98,102,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[8]  
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 158,757,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 26,905,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MStreet2445Member
[5]    
Quantico Building E [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,518,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
[1]    
Initial Cost, Buildings and Improvements 24,801,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
[1]    
Net Improvements (Retirement) since Acquisition 800,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,518,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,601,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 30,119,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
[2]    
Accumulated Depreciation at December 31, 2011 6,404,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
   
Year of Construction Jan. 01, 2007    
Date of Acquisition Jun. 01, 2010    
Net Rentable Square Feet 133,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 30,119,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 6,404,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingEMember
   
Quantico Building G [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,897,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
[1]    
Initial Cost, Buildings and Improvements 25,376,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
[1]    
Net Improvements (Retirement) since Acquisition 243,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,898,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 25,618,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 30,516,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
[2]    
Accumulated Depreciation at December 31, 2011 6,603,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
   
Year of Construction Jan. 01, 2009    
Date of Acquisition Jun. 01, 2010    
Net Rentable Square Feet 136,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 30,516,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 6,603,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_QuanticoBuildingGMember
   
1140 Connecticut Avenue [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 25,226,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
[1]    
Initial Cost, Buildings and Improvements 50,495,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
[1]    
Net Improvements (Retirement) since Acquisition 11,280,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 25,226,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 61,775,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 87,001,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
[2]    
Accumulated Depreciation at December 31, 2011 10,246,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
   
Year of Construction Jan. 01, 1966    
Date of Acquisition Jan. 01, 2011    
Net Rentable Square Feet 183,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 87,001,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 10,246,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1140ConnecticutAvenueMember
   
1227 25th Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 17,505,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
[1]    
Initial Cost, Buildings and Improvements 21,319,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 2,254,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 17,505,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 23,573,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 41,078,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 4,412,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
   
Year of Construction Jan. 01, 1988    
Date of Acquisition Mar. 01, 2011    
Net Rentable Square Feet 135,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 41,078,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 4,412,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A122725ThStreetMember
   
Braddock Place Member      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 18,817,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
[1]    
Initial Cost, Buildings and Improvements 71,250,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
[1]    
Net Improvements (Retirement) since Acquisition 10,450,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 18,818,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 81,699,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 100,517,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
[2]    
Accumulated Depreciation at December 31, 2011 12,291,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
   
Year of Construction Jan. 01, 1985    
Date of Acquisition Sep. 01, 2011    
Net Rentable Square Feet 353,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 100,517,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 12,291,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BraddockPlaceMember
   
John Marshall II Member      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia [5]    
Initial Cost, Land 13,490,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[1],[5]    
Initial Cost, Buildings and Improvements 53,024,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 176,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 13,490,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 53,200,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 66,690,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 7,297,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[5]    
Year of Construction Jan. 01, 1996    
Date of Acquisition Sep. 01, 2011    
Net Rentable Square Feet 223,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
   
Depreciation Life 30 years [6]    
Secured Debt 51,810,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
52,563,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
 
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 66,690,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 7,297,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_JohnMarshallIiMember
[5]    
Fairgate at Ballston [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 17,750,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
[1]    
Initial Cost, Buildings and Improvements 29,885,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
[1]    
Net Improvements (Retirement) since Acquisition 3,164,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 17,750,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 33,049,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 50,799,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
[2]    
Accumulated Depreciation at December 31, 2011 4,166,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
   
Year of Construction Jan. 01, 1988    
Date of Acquisition Jun. 01, 2012    
Net Rentable Square Feet 142,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 50,799,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 4,166,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FairgateAtBallstonMember
   
The Army Navy Club Building [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC [5]    
Initial Cost, Land 30,796,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[1],[5]    
Initial Cost, Buildings and Improvements 39,315,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 704,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 30,796,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 40,019,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 70,815,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 1,579,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[5]    
Year of Construction Jan. 01, 1912    
Date of Acquisition Mar. 01, 2014    
Net Rentable Square Feet 108,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
   
Depreciation Life 30 years [6]    
Secured Debt 52,235,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
0us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
 
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 70,815,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 1,579,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TheArmyNavyClubBuildingMember
[5]    
1775 Eye Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 48,086,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
[1]    
Initial Cost, Buildings and Improvements 51,074,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 2,151,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 48,086,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 53,225,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 101,311,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 1,659,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
   
Year of Construction Jan. 01, 1964    
Date of Acquisition May 01, 2014    
Net Rentable Square Feet 185,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 101,311,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 1,659,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A1775EyeStreetMember
   
Retail Centers [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Initial Cost, Land 132,594,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
[1]    
Initial Cost, Buildings and Improvements 258,603,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
[1]    
Net Improvements (Retirement) since Acquisition 73,020,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 132,888,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 331,329,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 464,217,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
[2]    
Accumulated Depreciation at December 31, 2011 107,810,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
   
Net Rentable Square Feet 2,524,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
   
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 464,217,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 107,810,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RetailCentersMember
   
Takoma Park [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 415,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
[1]    
Initial Cost, Buildings and Improvements 1,084,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
[1]    
Net Improvements (Retirement) since Acquisition 268,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 415,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 1,352,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 1,767,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
[2]    
Accumulated Depreciation at December 31, 2011 1,188,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
   
Year of Construction Jan. 01, 1962    
Date of Acquisition Jul. 01, 1963    
Net Rentable Square Feet 51,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
   
Depreciation Life 50 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 1,767,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 1,188,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_TakomaParkMember
   
Westminster [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 519,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
[1]    
Initial Cost, Buildings and Improvements 1,775,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
[1]    
Net Improvements (Retirement) since Acquisition 9,710,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 519,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,485,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 12,004,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
[2]    
Accumulated Depreciation at December 31, 2011 6,920,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
   
Year of Construction Jan. 01, 1969    
Date of Acquisition Sep. 01, 1972    
Net Rentable Square Feet 150,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
   
Depreciation Life 37 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 12,004,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 6,920,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WestminsterMember
   
Concord Centre [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 413,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
[1]    
Initial Cost, Buildings and Improvements 850,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
[1]    
Net Improvements (Retirement) since Acquisition 5,038,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 413,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 5,888,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 6,301,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
[2]    
Accumulated Depreciation at December 31, 2011 3,047,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
   
Year of Construction Jan. 01, 1960    
Date of Acquisition Dec. 01, 1973    
Net Rentable Square Feet 76,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
   
Depreciation Life 33 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 6,301,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 3,047,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ConcordCentreMember
   
Wheaton Park [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 796,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
[1]    
Initial Cost, Buildings and Improvements 857,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
[1]    
Net Improvements (Retirement) since Acquisition 4,576,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 796,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 5,433,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 6,229,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
[2]    
Accumulated Depreciation at December 31, 2011 3,567,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
   
Year of Construction Jan. 01, 1967    
Date of Acquisition Sep. 01, 1977    
Net Rentable Square Feet 74,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
   
Depreciation Life 50 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 6,229,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 3,567,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_WheatonParkMember
   
Bradlee [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 4,152,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
[1]    
Initial Cost, Buildings and Improvements 5,383,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
[1]    
Net Improvements (Retirement) since Acquisition 10,332,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,152,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 15,715,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 19,867,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
[2]    
Accumulated Depreciation at December 31, 2011 10,141,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
   
Year of Construction Jan. 01, 1955    
Date of Acquisition Dec. 01, 1984    
Net Rentable Square Feet 171,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
   
Depreciation Life 40 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 19,867,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 10,141,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_BradleeMember
   
Chevy Chase Metro Plaza [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 1,549,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
[1]    
Initial Cost, Buildings and Improvements 4,304,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
[1]    
Net Improvements (Retirement) since Acquisition 5,381,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 1,549,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 9,685,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 11,234,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
[2]    
Accumulated Depreciation at December 31, 2011 6,341,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
   
Year of Construction Jan. 01, 1975    
Date of Acquisition Sep. 01, 1985    
Net Rentable Square Feet 49,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
   
Depreciation Life 50 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 11,234,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 6,341,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ChevyChaseMetroPlazaMember
   
Montgomery Village Center [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 11,625,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
[1]    
Initial Cost, Buildings and Improvements 9,105,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
[1]    
Net Improvements (Retirement) since Acquisition 3,338,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 11,625,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 12,443,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 24,068,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
[2]    
Accumulated Depreciation at December 31, 2011 5,831,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
   
Year of Construction Jan. 01, 1969    
Date of Acquisition Dec. 01, 1992    
Net Rentable Square Feet 197,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
   
Depreciation Life 50 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 24,068,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 5,831,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontgomeryVillageCenterMember
   
Shoppes of Foxchase [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 5,838,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
[1]    
Initial Cost, Buildings and Improvements 2,979,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
[1]    
Net Improvements (Retirement) since Acquisition 14,039,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 5,838,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 17,018,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 22,856,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
[2]    
Accumulated Depreciation at December 31, 2011 6,008,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
   
Year of Construction Jan. 01, 1960    
Date of Acquisition Jun. 01, 1994    
Net Rentable Square Feet 134,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
   
Depreciation Life 50 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 22,856,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 6,008,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_ShoppesOfFoxchaseMember
   
Frederick County Square [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 6,561,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
[1]    
Initial Cost, Buildings and Improvements 6,830,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
[1]    
Net Improvements (Retirement) since Acquisition 4,421,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 6,561,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,251,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 17,812,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
[2]    
Accumulated Depreciation at December 31, 2011 6,864,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
   
Year of Construction Jan. 01, 1973    
Date of Acquisition Aug. 01, 1995    
Net Rentable Square Feet 227,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 17,812,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 6,864,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCountySquareMember
   
800 S. Washington Street [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Virginia    
Initial Cost, Land 2,904,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
[1]    
Initial Cost, Buildings and Improvements 5,489,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
[1]    
Net Improvements (Retirement) since Acquisition 6,024,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 2,904,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 11,513,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 14,417,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
[2]    
Accumulated Depreciation at December 31, 2011 4,471,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
   
Year of Construction Jan. 01, 1951    
Date of Acquisition Jun. 01, 1998    
Net Rentable Square Feet 47,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 14,417,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 4,471,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_A800SWashingtonStreetMember
   
Centre at Hagerstown . [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 13,029,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
[1]    
Initial Cost, Buildings and Improvements 25,415,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
[1]    
Net Improvements (Retirement) since Acquisition 2,383,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 13,029,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 27,798,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 40,827,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
[2]    
Accumulated Depreciation at December 31, 2011 11,851,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
   
Year of Construction Jan. 01, 2000    
Date of Acquisition Jun. 01, 2002    
Net Rentable Square Feet 332,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 40,827,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 11,851,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_CentreAtHagerstownMember
   
Frederick Crossing [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 12,759,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
[1]    
Initial Cost, Buildings and Improvements 35,477,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
[1]    
Net Improvements (Retirement) since Acquisition 2,235,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 12,759,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 37,712,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 50,471,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
[2]    
Accumulated Depreciation at December 31, 2011 13,076,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
   
Year of Construction Jan. 01, 1999    
Date of Acquisition Mar. 01, 2005    
Net Rentable Square Feet 295,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 50,471,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 13,076,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_FrederickCrossingMember
   
Randolph Shopping Center [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 4,928,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
[1]    
Initial Cost, Buildings and Improvements 13,025,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
[1]    
Net Improvements (Retirement) since Acquisition 752,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 4,928,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 13,777,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 18,705,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
[2]    
Accumulated Depreciation at December 31, 2011 4,315,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
   
Year of Construction Jan. 01, 1972    
Date of Acquisition May 01, 2006    
Net Rentable Square Feet 82,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 18,705,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 4,315,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_RandolphShoppingCenterMember
   
Montrose Shopping Center [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 11,612,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
[1]    
Initial Cost, Buildings and Improvements 22,410,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
[1]    
Net Improvements (Retirement) since Acquisition 2,500,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 11,612,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 24,910,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 36,522,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
[2]    
Accumulated Depreciation at December 31, 2011 7,714,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
   
Year of Construction Jan. 01, 1970    
Date of Acquisition May 01, 2006    
Net Rentable Square Feet 145,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 36,522,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 7,714,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_MontroseShoppingCenterMember
   
Gateway Overlook [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland    
Initial Cost, Land 28,816,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
[1]    
Initial Cost, Buildings and Improvements 52,249,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
[1]    
Net Improvements (Retirement) since Acquisition 235,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 29,110,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 52,190,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 81,300,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
[2]    
Accumulated Depreciation at December 31, 2011 10,989,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
   
Year of Construction Jan. 01, 2007    
Date of Acquisition Dec. 01, 2010    
Net Rentable Square Feet 220,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 81,300,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 10,989,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_GatewayOverlookMember
   
Olney Village Center Member      
Real Estate and Accumulated Depreciation [Line Items]      
Location Maryland [5]    
Initial Cost, Land 15,842,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[1],[5]    
Initial Cost, Buildings and Improvements 39,133,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[1],[5]    
Net Improvements (Retirement) since Acquisition 1,729,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Land 15,842,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 40,862,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[5]    
Gross Amounts at Which Carried at December 31, 2011, Total 56,704,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[2],[5]    
Accumulated Depreciation at December 31, 2011 5,214,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[5]    
Year of Construction Jan. 01, 1979 [5]    
Date of Acquisition Aug. 01, 2011 [5]    
Net Rentable Square Feet 199,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
   
Depreciation Life 30 years [6]    
Secured Debt 19,070,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
20,743,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
 
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 56,704,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[2],[5]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 5,214,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_OlneyVillageCenterMember
[5]    
Spring Vally Retail Center [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Location Washington, DC    
Initial Cost, Land 10,836,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
[1]    
Initial Cost, Buildings and Improvements 32,238,000us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
[1]    
Net Improvements (Retirement) since Acquisition 59,000us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Land 10,836,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Buildings and Improvements 32,297,000us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
   
Gross Amounts at Which Carried at December 31, 2011, Total 43,133,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
[2]    
Accumulated Depreciation at December 31, 2011 273,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
   
Year of Construction Jan. 01, 1941    
Date of Acquisition Oct. 01, 2014    
Net Rentable Square Feet 75,000wre_NetRentableSquareFeet
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
   
Depreciation Life 30 years [6]    
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Balance, end of period 43,133,000us-gaap_RealEstateGrossAtCarryingValue
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
[2]    
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Balance, end of period 273,000us-gaap_RealEstateAccumulatedDepreciation
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_SpringVallyRetailCenterMember
   
Kenmore Apartments [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Secured Debt $ 34,305,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreApartmentsMember
$ 34,937,000us-gaap_SecuredDebt
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= wre_KenmoreApartmentsMember
 
Minimum [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Useful Life 3 years    
Maximum [Member]      
Real Estate and Accumulated Depreciation [Line Items]      
Useful Life 50 years    
[1] The purchase cost of real estate investments has been divided between land and buildings and improvements on the basis of management’s determination of the fair values.
[2] At December 31, 2014, total land, buildings and improvements are carried at $2,113.2 million for federal income tax purposes.
[3] Residential properties are presented in gross square feet.
[4] Includes non-cash accruals for capital items and assumed mortgages.
[5] At December 31, 2014, our properties were encumbered by non-recourse mortgage amounts as follows: $35.4 million on 3801 Connecticut Avenue, $16.5 million on Walker House, $29.1 million on Bethesda Hill, $34.3 million on The Kenmore, $99.4 million on 2445 M Street, $51.8 million on John Marshall II, and $19.1 million on Olney Village Center, $53.0 million on Yale West, and $52.2 million on The Amy Navy Club Building.
[6] The useful life shown is for the main structure. Buildings and improvements are depreciated over various useful lives ranging from 3 to 50 years.
[7] As of December 31, 2014, Washington REIT had under development via joint venture arrangements, a mid-rise multifamily property in Arlington, Virginia (The Maxwell) and a high-rise multifamily property in Alexandria, Virginia (1225 First Street). The value not yet placed into service for The Maxwell at December 31, 2014 was $17.9 million. The value not yet placed into service for 1225 First Street at December 31, 2014 was $20.8 million. The Maxwell was encumbered by a construction loan with a $27.7 million balance at December 31, 2014.
[8] Interest only is payable monthly until the maturity date upon which all unpaid principal and interest are payable in full.
[9] Interest rate on The Maxwell is variable, based on LIBOR plus 2.15%. The maturity date can be extended for up to two years, subject to fees and compliance with certain provisions in the loan agreement, until February 20, 2018.
[10] As of December 31, 2014, Washington REIT had under development an office project with 360,000 square feet of office space and a parking garage to be developed in Herndon, VA (Dulles Station, Phase II). The value not yet placed in service of Dulles Station, Phase II at December 31, 2014 was $8.5 million. $3.6 million of Dulles Station, Phase II was placed into service upon the completion of a portion of the parking garage structure. Additionally, Washington REIT had investments in various development or redevelopment projects, including Silverline Center. The value of this redevelopment not yet placed in service is $26.1 million at December 31, 2014.