Annual report pursuant to Section 13 and 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 $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures $ 132,339 $ 32,015
Plaza VIII & IX Associates, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 4,321 4,291
South Pier At Harborside [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures (1,225) (343)
Red Bank Corporate Plaza, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 3,876 3,676
12 Vreeland Associates, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 12,840 10,233
Boston Downtown Crossing [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 13,012 13,005
Gale Jefferson, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 1,029 1,153
Stamford SM LLC [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 34,006  
Marbella RoseGarden, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 16,918  
RoseGarden Monaco Holdings, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 4,761  
Rosewood Lafayette Holdings, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 1,988  
PruRose Port Imperial South 15, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 606  
Rosewood Morristown, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 7,091  
Overlook Ridge, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 31  
Overlook Ridge JV 2C/3B, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 179  
Roseland/North Retail, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 2,161  
BNES Associates III [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 1,955  
Portside Master Company, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 3,651  
PruRose Port Imperial South 13, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 2,920  
Roseland/Port Imperial Partners, L.P. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 2,582  
RoseGarden Marbella South, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 6,182  
PruRose Riverwalk G, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 4,136  
Elmajo Urban Renewal Associates, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 849  
Riverpark At Harrison I, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 2,606  
150 Main Street, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 2,395  
RoseGarden Monaco, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 1,165  
Hillsborough 206 Holdings, L.L.C. [Member]
   
Schedule of Equity Method Investments [Line Items]    
Company's investments in unconsolidated joint ventures 1,967  
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