Recent Transactions (Summary Of Income From Property Held For Sale, Net) (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Less - Accumulated depreciation $ (1,072,029) $ (1,087,083)
Rental property held for sale, net 56,419 $ 171,578
Paramus, Hamilton And Rochelle Park, New Jersey And White Plains, New York [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member]    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]    
Land 13,472  
Buildings and improvements 87,969  
Less - Accumulated depreciation (44,522)  
Less: Unrealized losses on properties held for sale (500)  
Rental property held for sale, net $ 56,419