Recent Transactions (Summary Of Income From Property Held For Sale, Net) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Less - Accumulated depreciation	$ (896,777)	$ (1,097,868)
Rental property held for sale, net	384,138	$ 108,848
Fort Lee, Parsippany, Hanover And Neptune, New Jersey, And Malden And Revere, Massachusetts [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	96,586
Buildings and improvements	426,349
Less - Accumulated depreciation	(103,718)
Less: Cumulative unrealized losses on property held for sale	(35,079)
Rental property held for sale, net	$ 384,138