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
|
|
|
|