Investments In Unconsolidated Joint Ventures (Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ (2,329)	$ 443	$ (5,858)	$ (792)
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	61	(9)	122	(15)
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(313)	(238)	(629)	(515)
Rosewood Lafayette Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		(203)	(62)	(419)
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(91)	(76)	(185)	(174)
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	(27)		(247)	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	(276)	(613)	(530)	(1,151)
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		(91)		(203)
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	13	53	3	(274)
Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(637)	(220)	(1,357)	(434)
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	(506)	(213)	(731)	(418)
Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(125)	(180)	(309)	(345)
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	(150)		(324)
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(1,263)		(1,188)
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		(212)		(212)
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		(16)	(19)	(54)
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	112	106	222	205
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	86	54	72	144
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	52	110	121	147
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)		(5)	(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	(379)	(483)	(763)	(1,136)
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(242)		(1,590)
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	232	251	428	251
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	70	44	156	146
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)	(23)	(36)	(47)
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	868	892	784	1,290
Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures		928		1,844
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ 209	$ 582	$ 209	$ 536