Investments In Unconsolidated Joint Ventures (Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ (3,172)	$ (2,423)	$ (2,327)
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	231	(19)	(540)
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(1,224)	(1,040)	(1,560)
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)	(853)	(1,131)
PruRose Port Imperial South 15, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures			(606)
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(364)	(345)	(509)
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	(371)	(384)	293
PruRose Riverwalk G, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(955)	(2,139)	(985)
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		(203)	(345)
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(123)	(139)	(2,639)
Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(1,736)	(1,163)	(421)
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	(988)	(863)	(664)
Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(474)	(646)	(740)
RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures			(57)
Estuary Urban Renewal Unit B, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	1	(15)	(157)
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	(363)	(150)
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(3,687)	(75)
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		(218)
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	(32)	(54)	(77)
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	392	380	372
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	270	106	74
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	115	240	(14)
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)	(10)	(35)
KPG-P 100 IMW JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(800)	(1,887)	(913)
Keystone-Penn [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	3,812
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(2,182)	(318)
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	475	624
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	344	320	99
Roseland/North Retail, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(70)	(102)	(230)
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	3,036	2,602	2,519
Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		2,337	3,719
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ 1,588	$ 1,591	$ 2,220