Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Details)

v3.7.0.1
Stock Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense $ 1.2 $ 0.9 $ 2.4 $ 2.4
Restricted Share Awards        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Fair value of share grants vested     $ 2.0 $ 2.5
Total unvested restricted share awards (in shares) 356,093   356,093  
Weighted average grant date fair value (in dollars per share) $ 30.85   $ 30.85  
Total compensation costs, non-vested restricted share awards $ 8.3   $ 8.3  
Total compensation cost not yet recognized, period for recognition (in months)     39 months  
Washington Real Estate Investment Trust 2016 Omnibus Long Term Incentive Plan [Domain]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock based plan, aggregate number of shares authorized (in shares) 2,400,000.0   2,400,000.0  
Stock based plan, period in effect (in years)     10 years