Recent Transactions (Rental Property Held for Sale, Net) (Narrative) (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
$ in Thousands |
6 Months Ended |
|
Jun. 30, 2018
USD ($)
ft²
property
|
|---|
| Office [Member] |
|
| Real Estate Properties [Line Items] |
|
| Unrealized losses on rental properties held for sale |
$ 500
|
| Paramus, Hamilton And Rochelle Park, New Jersey And White Plains, New York [Member] |
|
| Real Estate Properties [Line Items] |
|
| Unrealized losses on properties held for sale |
500
|
| Assets held for sale, Deferred charges and other assets |
3,400
|
| Assets held for sale, Unbilled rents receivable, net |
1,100
|
| Assets held for sale, Accounts payable, accrued expenses and other liabilities |
2,100
|
| Expected assets to be written off |
4,100
|
| Expected liabilities to be written off |
$ 1,100
|
| Paramus, Hamilton And Rochelle Park, New Jersey And White Plains, New York [Member] | Office [Member] |
|
| Real Estate Properties [Line Items] |
|
| Area of property (in square feet) | ft² |
629,000
|
| Number of properties held for sale | property |
5
|
| Unrealized losses on properties held for sale |
$ 500
|
| Estimated expected sales proceeds |
$ 70,500
|