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, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ (614)	$ (2,329)	$ (2,168)	$ (5,858)
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	47	61	132	122
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(300)	(313)	(592)	(629)
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(82)	(91)	(163)	(185)
Riverwalk G Urban Renewal, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(595)	(276)	(595)	(530)
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(110)	13	(222)	3
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)		(309)
RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(307)		(307)
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	(102)	(150)	(130)	(324)
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(727)	(1,263)	(1,495)	(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			(17)
Grand Jersey Waterfront URA, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures			(60)	(19)
Hillsborough 206 Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(13)	(5)	(32)	(5)
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	98	70	175	156
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	108	112	210	222
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	108	86	192	72
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	17	52	(177)	121
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)		(763)
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(191)	(242)	(668)	(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	226	232	405	428
Roseland/North Retail, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	(9)	(18)	(25)	(36)
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	987	868	820	784
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	$ 231	$ (961)	$ 381	$ (2,188)