Quarterly report pursuant to Section 13 or 15(d)

Recent Transactions (Schedule Of Property Sold And Disposed) (Details)

v3.4.0.3
Recent Transactions (Schedule Of Property Sold And Disposed) (Details)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2016
USD ($)
ft²
item
Dec. 31, 2015
USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Number of Buildings | item 2  
Rentable Square Feet | ft² 236,950  
Net Sales Proceeds $ 94,710  
Net Book Value 36,110  
Realized Gain (loss) 58,600  
Mortgage loans, carrying amount $ 1,823,311  
2 Independence Way [Member]    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Number of Buildings | item [1] 1  
Rentable Square Feet | ft² [1] 67,401  
Net Sales Proceeds [1] $ 4,119  
Net Book Value [1] 4,283  
Realized Gain (loss) [1] $ (164)  
Impairments   $ 3,200
1201 Connecticut Avenue NW [Member]    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Number of Buildings | item 1  
Rentable Square Feet | ft² 169,549  
Net Sales Proceeds $ 90,591  
Net Book Value 31,827  
Realized Gain (loss) $ 58,764  
[1] The Company recorded an impairment charge of $3.2 million on this property during the year ended December 31, 2015 as it estimated that the carrying value of the property may not be recoverable over its anticipated holding period.