Investments In Unconsolidated Joint Ventures (Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		$ 1,572		$ (51)
Amortization of basis difference		289		259
Urby At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Economic tax credit certificate income		$ 2,600
Period of venture agreement to sell economic tax credit		9 years
Annual proceeds from economic tax credit		$ 3,000
Total proceeds from economic tax credit		27,000
Unconsolidated Joint Venture Multi-Family Properties [Member] | Marbella [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		91		109
Unconsolidated Joint Venture Multi-Family Properties [Member] | Metropolitan At 40 Park [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		(75)		(85)
Unconsolidated Joint Venture Multi-Family Properties [Member] | RiverTrace At Port Imperial [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		44		48
Unconsolidated Joint Venture Multi-Family Properties [Member] | Crystal House [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		(162)		(293)
Unconsolidated Joint Venture Multi-Family Properties [Member] | PI North - Riverwalk C [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures				(131)
Unconsolidated Joint Venture Multi-Family Properties [Member] | Marbella II [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		22		27
Unconsolidated Joint Venture Multi-Family Properties [Member] | Riverpark At Harrison [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		(63)		(11)
Unconsolidated Joint Venture Multi-Family Properties [Member] | Station House [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		(428)		(375)
Unconsolidated Joint Venture Multi-Family Properties [Member] | Urby At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		1,721	[1]	(145)
Unconsolidated Joint Venture Multi-Family Properties [Member] | Liberty Landing [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures				(15)
Unconsolidated Joint Venture Multi-Family Properties [Member] | Hillsborough 206 [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		16		(25)
Unconsolidated Joint Venture Office Buildings [Member] | Red Bank [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		(74)		106
Unconsolidated Joint Venture Office Buildings [Member] | 12 Vreeland Rd [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		59		77
Unconsolidated Joint Venture Office Buildings [Member] | Offices At Crystal Lake [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		26		6
Unconsolidated Joint Venture Other Property [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures	[2]	1,572		(51)
Unconsolidated Joint Venture Other Property [Member] | Riverwalk Retail [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		(25)		(11)
Unconsolidated Joint Venture Other Property [Member] | Hyatt Regency Jersey City [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		310		587
Unconsolidated Joint Venture Other Property [Member] | Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings of unconsolidated joint ventures		$ 110		$ 80

[1] Includes $2.6 million of the Company's share of the venture's income from its first annual sale of an economic tax credit certificate from the State of New Jersey to a third party. The venture has an agreement with a third party to sell it the tax credits over the next nine years for $3 million per year for a total of $27 million. The sales are subject to the venture obtaining the tax credits from the State of New Jersey and transferring the credit certificates each year.

[2] Amounts are net of amortization of basis differences of $289 and $259 for the three months ended March 31, 2018 and 2017, respectively.