Recent Transactions (Summary Of Income From Property Held For Sale, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Less - Accumulated depreciation	$ (1,097,868)	$ (1,087,083)
Rental property held for sale, net	108,848	171,578
Fort Lee, Newark, Paramus, Bridgewater, Morris Plains And Rahway, New Jersey [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	24,376
Buildings and improvements	159,857
Less - Accumulated depreciation	(55,250)
Less: Unrealized losses on properties held for sale	(20,135)
Rental property held for sale, net	$ 108,848
Parsippany, Paramus, Rochelle Park, Hamilton And Wall, 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		37,024
Buildings and improvements		273,388
Less - Accumulated depreciation		(126,503)
Less: Unrealized losses on properties held for sale		(12,331)
Rental property held for sale, net		$ 171,578