Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Details)

v2.4.1.9
Stock Based Compensation (Details) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense $ 1.9us-gaap_AllocatedShareBasedCompensationExpense $ 1.1us-gaap_AllocatedShareBasedCompensationExpense
Restricted Share Awards [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Fair value of share grants vested 1.7us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue
/ us-gaap_AwardTypeAxis
= wre_RestrictedShareAwardsMember
0.2us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue
/ us-gaap_AwardTypeAxis
= wre_RestrictedShareAwardsMember
Total unvested restricted share awards (in shares) 230,237us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= wre_RestrictedShareAwardsMember
 
Weighted average grant date fair value (in dollars per share) $ 27.26us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= wre_RestrictedShareAwardsMember
 
Total compensation costs, non-vested restricted share awards $ 3.7us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= wre_RestrictedShareAwardsMember
 
Total compensation cost not yet recognized, period for recognition (in months) 23 months  
Washington Real Estate Investment Trust 2007 Omnibus Long-Term Incentive Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock based plan, aggregate number of shares authorized (in shares) 2,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= wre_WashingtonRealEstateInvestmentTrust2007OmnibusLongTermIncentivePlanMember
 
Stock based plan, period in effect (in years) 10 years