Quarterly report pursuant to Section 13 or 15(d)

Investments In Unconsolidated Joint Ventures (Summary Of Company's Investment In Unconsolidated Joint Ventures) (Details)

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Investments In Unconsolidated Joint Ventures (Summary Of Company's Investment In Unconsolidated Joint Ventures) (Details) (USD $)
Mar. 31, 2014
Dec. 31, 2013
Dec. 23, 2013
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures $ 179,656,000 $ 181,129,000  
Accounts payable, accrued expenses and other liabilities 147,357,000 121,286,000  
Plaza VIII & IX Associates, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 3,804,000 3,702,000  
South Pier At Harborside [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures    [1]    [1]  
Accounts payable, accrued expenses and other liabilities 2,308,018 1,706,000  
Red Bank Corporate Plaza, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 4,153,000 4,046,000  
12 Vreeland Associates, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 5,604,000 5,514,000  
Stamford SM LLC [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 36,835,000 36,258,000  
Marbella RoseGarden, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 15,791,000 15,797,000  
RoseGarden Monaco Holdings, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 2,925,000 3,201,000  
Rosewood Lafayette Holdings, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 641,000 857,000  
Rosewood Morristown, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 6,336,000 6,455,000  
Roseland/North Retail, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 1,906,000 1,930,000  
BNES Associates III [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 1,790,000 1,753,000  
Portside Master Company, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 2,950,000 3,207,000  
PruRose Port Imperial South 13, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 1,982,000 2,206,000  
Roseland/Port Imperial Partners, L.P. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 2,017,000 2,068,000  
RoseGarden Marbella South, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 7,951,000 7,567,000  
PruRose Riverwalk G, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 2,579,000 3,117,000  
Elmajo Urban Renewal Associates, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 91,000 203,000  
Estuary Urban Renewal Unit B, LLC [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures   24,000  
RiverPark At Harrison I, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 3,808,000 3,655,000  
RoseGarden Monaco, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 1,239,000 1,224,000  
Hillsborough 206 Holdings, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 1,962,000 1,962,000  
Grand Jersey Waterfront Urban Renewal Associates, L.L.C. [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 337,000 337,000  
Crystal House Apartments Investors LLC [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 26,326,000 26,838,000  
KPG-P 100 IMW JV, LLC [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 1,234,000 1,887,000  
Capitol Place Mezz LLC [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures 47,302,000 46,628,000 46,500,000
Other [Member]
      
Schedule of Equity Method Investments [Line Items]      
Company's investments in unconsolidated joint ventures $ 93,000 $ 693,000  
[1] The negative investment balance for this joint venture of $2,308,018 and $1,706,000 as of March 31, 2014 and December 31, 2013, respectively, were included in accounts payable, accrued expenses and other liabilities.