Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Details)

v2.4.0.6
Stock Based Compensation (Details) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense $ 1.3 $ 1.5 $ 2.7 $ 2.8
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 2,000,000   2,000,000  
Stock based plan, period in effect (in years) 10   10  
Share Grants [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total compensation costs, non-vested restricted share awards 4.2   4.2  
Total compensation cost not yet recognized, period for recognition (in months)     24  
Restricted Share Awards [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Fair value of share grants vested $ 0 $ 0 $ 0.3 $ 0.3
Total unvested restricted share awards (in shares) 313,500   313,500  
Weighted average grant date fair value $ 28.40   $ 28.40