Investments In Unconsolidated Joint Ventures (Summary Of The Results Of Financial Position) (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]    
Rental property, net $ 140,621 $ 143,369
Loan receivable 40,954  
Other assets 76,931 71,920
Total assets 258,506 215,289
Mortgages, loans payable and other obligations 138,833 140,975
Other liabilities 11,505 6,884
Partners'/members' capital (deficit) 108,168 67,430
Total liabilities and partners'/members' capital (deficit) 258,506 215,289
Company's investments in unconsolidated joint ventures, net 64,359 32,015
Plaza VIII & IX Associates [Member]
    
Schedule of Equity Method Investments [Line Items]    
Rental property, net 8,028 8,335
Other assets 1,289 933
Total assets 9,317 9,268
Other liabilities 537 531
Partners'/members' capital (deficit) 8,780 8,737
Total liabilities and partners'/members' capital (deficit) 9,317 9,268
Company's investments in unconsolidated joint ventures, net 4,312 4,291
Harborside South Pier [Member]
    
Schedule of Equity Method Investments [Line Items]    
Rental property, net 57,319 59,733
Other assets 16,913 12,840
Total assets 74,232 72,573
Mortgages, loans payable and other obligations 70,127 70,690
Other liabilities 9,095 4,982
Partners'/members' capital (deficit) (4,990) (3,099)
Total liabilities and partners'/members' capital (deficit) 74,232 72,573
Company's investments in unconsolidated joint ventures, net (1,289) (343)
Red Bank Corporate Plaza [Member]
    
Schedule of Equity Method Investments [Line Items]    
Rental property, net 22,549 22,903
Other assets 2,836 2,909
Total assets 25,385 25,812
Mortgages, loans payable and other obligations 17,728 18,100
Other liabilities 42 117
Partners'/members' capital (deficit) 7,615 7,595
Total liabilities and partners'/members' capital (deficit) 25,385 25,812
Company's investments in unconsolidated joint ventures, net 3,702 3,676
Gramercy Agreement [Member]
    
Schedule of Equity Method Investments [Line Items]    
Rental property, net 38,704 39,276
Other assets 5,599 5,669
Total assets 44,303 44,945
Mortgages, loans payable and other obligations 50,978 50,978
Other liabilities 1,106 1,086
Partners'/members' capital (deficit) (7,781) (7,119)
Total liabilities and partners'/members' capital (deficit) 44,303 44,945
12 Vreeland [Member]
    
Schedule of Equity Method Investments [Line Items]    
Rental property, net 14,021 13,122
Other assets 1,024 521
Total assets 15,045 13,643
Mortgages, loans payable and other obligations   1,207
Other liabilities 725 168
Partners'/members' capital (deficit) 14,320 12,268
Total liabilities and partners'/members' capital (deficit) 15,045 13,643
Company's investments in unconsolidated joint ventures, net 10,558 10,233
Boston-Downtown Crossing [Member]
    
Schedule of Equity Method Investments [Line Items]    
Other assets 46,213 46,121
Total assets 46,213 46,121
Partners'/members' capital (deficit) 46,213 46,121
Total liabilities and partners'/members' capital (deficit) 46,213 46,121
Company's investments in unconsolidated joint ventures, net 13,010 13,005
Gale Jefferson [Member]
    
Schedule of Equity Method Investments [Line Items]    
Other assets 2,830 2,927
Total assets 2,830 2,927
Partners'/members' capital (deficit) 2,830 2,927
Total liabilities and partners'/members' capital (deficit) 2,830 2,927
Company's investments in unconsolidated joint ventures, net 1,121 1,153
Stamford SM LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Loan receivable 40,954  
Other assets 227  
Total assets 41,181  
Partners'/members' capital (deficit) 41,181  
Total liabilities and partners'/members' capital (deficit) 41,181  
Company's investments in unconsolidated joint ventures, net $ 32,945