Quarterly report pursuant to Section 13 or 15(d)

Recent Transactions (Dispositions) (Narrative) (Details)

v3.3.0.814
Recent Transactions (Dispositions) (Narrative) (Details)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Jun. 26, 2015
USD ($)
ft²
Jun. 01, 2015
USD ($)
item
Jan. 15, 2015
USD ($)
ft²
Sep. 30, 2015
USD ($)
ft²
property
Jun. 30, 2015
USD ($)
ft²
property
Sep. 30, 2014
USD ($)
Sep. 30, 2015
USD ($)
ft²
Sep. 30, 2014
USD ($)
Dec. 31, 2014
property
Dec. 31, 2013
USD ($)
Apr. 01, 2015
item
Real Estate Properties [Line Items]                      
Sales proceeds $ 80,000           $ 81,049 $ 274,839      
Mortgage loan       $ 1,784,744     1,784,744        
Impairment charge       164,176     164,176        
Realized gains on dispositions, net       $ 18,718   $ 264 $ 53,261 $ 54,848      
Number of properties sold | property                 16    
City Square Project [Member]                      
Real Estate Properties [Line Items]                      
Number of units | item                     365
1451 Metropolitan Drive [Member]                      
Real Estate Properties [Line Items]                      
Sales proceeds     $ 1,100                
Realized gains on dispositions, net     $ 100                
Area of property sold (in square feet) | ft²     21,600                
14 Sylvan Way [Member]                      
Real Estate Properties [Line Items]                      
Realized gains on dispositions, net $ 24,700                    
Area of property sold (in square feet) | ft² 203,506                    
4 Sylvan Way [Member]                      
Real Estate Properties [Line Items]                      
Area Of Real Estate Property | ft²         105,135            
Mortgage loan         $ 14,600            
Mortgage loan, maturity date       Aug. 11, 2014              
10 Independence [Member]                      
Real Estate Properties [Line Items]                      
Area Of Real Estate Property | ft²         120,528            
Mortgage loan         $ 16,900            
Mortgage loan, maturity date       Aug. 11, 2014              
4 Sylvan Way And 10 Independence [Member]                      
Real Estate Properties [Line Items]                      
Number of properties transferred | property         2            
Rosewood Lafayette Holdings, L.L.C. [Member]                      
Real Estate Properties [Line Items]                      
Percentage of interest in venture   25.00%                  
Number of units | item   217                  
Realized gains on dispositions, net   $ 6,400                  
5 Becker And 210 Clay [Member]                      
Real Estate Properties [Line Items]                      
Number of properties transferred | property       2              
5 Becker [Member]                      
Real Estate Properties [Line Items]                      
Area Of Real Estate Property | ft²       118,343     118,343        
Mortgage loan       $ 14,400     $ 14,400        
Mortgage loan, maturity date       May 11, 2016              
210 Clay [Member]                      
Real Estate Properties [Line Items]                      
Area Of Real Estate Property | ft²       121,203     121,203        
Mortgage loan       $ 13,800     $ 13,800        
Mortgage loan, maturity date       May 11, 2016              
4 Sylvan Way, 10 Independence, 5 Becker And 210 Clay [Member]                      
Real Estate Properties [Line Items]                      
Impairment charge                   $ 25,200  
Realized gains on dispositions, net       $ 18,700     $ 28,400