Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Narrative) (Details)

v2.3.0.15
Stock Based Compensation (Narrative) (Details) (USD $)
9 Months Ended 0 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended
Sep. 30, 2011
New STIP [Member]
Sep. 30, 2011
New STIP [Member]
Performance-Based Awards [Member]
Sep. 30, 2011
New STIP [Member]
Performance-Based Awards [Member]
Cash [Member]
Sep. 30, 2011
New STIP [Member]
Performance-Based Awards [Member]
Restricted Share Units [Member]
Sep. 30, 2011
New STIP [Member]
Service-Based Awards [Member]
Sep. 30, 2011
New STIP [Member]
Service-Based Awards [Member]
Restricted Share Units [Member]
Sep. 30, 2011
New LTIP [Member]
Sep. 30, 2011
New LTIP [Member]
Restricted Share Units [Member]
Sep. 30, 2011
New LTIP [Member]
Unrestricted Share Units [Member]
Sep. 30, 2011
New LTIP [Member]
Restricted Share Awards [Member]
Sep. 30, 2011
New LTIP [Member]
Unrestricted Share Awards [Member]
Feb. 17, 2011
Prior LTIP [Member]
Sep. 30, 2011
Prior LTIP [Member]
Sep. 30, 2011
Washington Real Estate Investment Trust 2007 Omnibus Long-Term Incentive Plan [Member]
Sep. 30, 2011
Vest On December 31, 2011 [Member]
Restricted Share Units [Member]
Sep. 30, 2011
Vest On December 31, 2012 [Member]
Restricted Share Units [Member]
Sep. 30, 2011
Restricted And Unrestricted Shares [Member]
Sep. 30, 2011
Restricted And Unrestricted Shares [Member]
months
Sep. 30, 2011
Options [Member]
years
Sep. 30, 2011
Restricted Share Units [Member]
Sep. 30, 2011
Restricted Share Units [Member]
Sep. 30, 2011
Restricted Share Awards [Member]
Sep. 30, 2011
Unrestricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                              
Stock based plan, aggregate number of shares authorized                           2,000,000                  
Stock based plan, period in effect (in years)                           10                  
Percentage of awards earned     50.00% 50.00%   15.00%   50.00% 50.00%                            
Performance period (years) 1           3                                
Vesting period (in years) four three     three     one         five                    
Percentage of cash portion pursuant to deferred compensation plan 80.00%                                            
Percentage of deferred amounts in restricted cash 25.00%                                            
Percentage of restricted shares subject to performance conditions 20.00%           60.00%                                
Percentage of potential award depend upon market condition             40.00%                                
Length of compensation expense recognition period (in years)                   4 3   6                    
Number of restricted shares subsequent to adoption of new share-based compensation plan                       154,400                      
Options outstanding                                     103,102        
Exercise price, minimum                                     $ 24.85        
Exercise price, maximum                                     $ 33.09        
Weighted average exercise price, options outstanding                                     $ 27.31        
Weighted average remaining contractual term, options outstanding (years)                                     1.6        
Aggregate intrinsic value of outstanding exercisable shares                                     $ 100,000        
Options exercised                                     42,883        
Aggregate intrinsic value of options exercised                                     200,000        
Total Fair value of vested shares                                   28,800   0 247,100    
Shares vested                                 0 0          
Remaining unvested restricted shares granted                         0         0          
Value of unvested restricted share units                                         4,100,000    
Weighted average period of recognition, compensation cost (months)                                   27     27    
Restricted shares granted during the period                                   10,822          
Fair value at grant date                                 300,000 300,000          
Unamortized value of unvested share awards                                 265,600 265,600          
Compensation cost of restricted shares                                 600,000 600,000          
Weighted average period of recognition, unamortized value (months)                                   28     28 39 27
Total number of share units awarded                             89,000 65,400              
Future expected expense expected to be awarded to non-officers                                         $ 800,000