Investments In Unconsolidated Joint Ventures (Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ (3,529)	$ (1,235)
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	61	(6)
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(317)	(277)
Rosewood Lafayette Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(62)	(216)
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(94)	(98)
Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(220)	62
PruRose Riverwalk G, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(254)	(538)
Elmajo Urban Renewal Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		(112)
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(10)	(327)
Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(719)	(213)
PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(225)	(206)
Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(184)	(164)
Estuary Urban Renewal Unit B, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		(15)
RiverPark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(173)
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	75
Grand Jersey Waterfront Urban Renewal Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(19)	(37)
Red Bank Corporate Plaza, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	110	99
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(14)	89
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	68	36
Hillsborough 206 Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		(5)
KPG-P 100 IMW JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(384)	(653)
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(1,348)
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	196
Plaza VIII & IX Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	86	102
Roseland/North Retail, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(18)	(24)
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(84)	398
Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		916
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		$ (46)