Investments In Unconsolidated Joint Ventures (Summary Of Unconsolidated Joint Ventures) (Details)
$ in Thousands
 6 Months Ended
Feb. 28, 2019
USD ($)
Jan. 31, 2019
USD ($)
item
Jan. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
ft²
item
Jun. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
Schedule of Equity Method Investments [Line Items]            
Carrying Value       $ 215,957   $ 232,750
Purchase price of property       $ 70,577 $ 97,085  
Minimum [Member]            
Schedule of Equity Method Investments [Line Items]            
Company's Effective Ownership %       20.00%    
Maximum [Member]            
Schedule of Equity Method Investments [Line Items]            
Company's Effective Ownership %       85.00%    
Crystal House [Member]            
Schedule of Equity Method Investments [Line Items]            
Percentage of interest in developable land       50.00%    
Number of units available for development | item       295    
Number of approved units available for development | item       252    
PI North - Riverwalk C [Member] | Construction Loan [Member]            
Schedule of Equity Method Investments [Line Items]            
Maximum borrowing capacity       $ 112,000    
Urby At Harborside [Member] | Construction/Permanent Loan [Member]            
Schedule of Equity Method Investments [Line Items]            
Company's Effective Ownership %       85.00%    
Red Bank [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       836    
Residual ownership interest       20.00%    
Percentage of interest sold 50.00%          
Gain on sale $ 900          
The Shops At 40 Park Property [Member] | Metropolitan At 40 Park [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       50,973    
Balance       $ 6,067    
Property Debt, Maturity Date       Sep. 01, 2019    
Property Debt, Interest Rate, Spread Over LIBOR       2.25%    
Residual ownership interest       25.00%    
Lofts At 40 Park Property [Member] | Metropolitan At 40 Park [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       59    
Indirect ownership interest       50.00%    
Number of stories | item       5    
Lofts At 40 Park Property [Member] | Metropolitan At 40 Park [Member] | Construction Loan [Member]            
Schedule of Equity Method Investments [Line Items]            
Balance       $ 13,145    
Property Debt, Maturity Date       Feb. 01, 2020    
Property Debt, Interest Rate, Spread Over LIBOR       2.50%    
Maximum borrowing capacity       $ 13,950    
Metropolitan Property [Member] | Metropolitan At 40 Park [Member]            
Schedule of Equity Method Investments [Line Items]            
Balance       $ 35,590    
Property Debt, Maturity Date       Sep. 01, 2020    
Property Debt, Interest Rate       3.25%    
Unconsolidated Joint Venture Multi-Family Properties [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       2,611    
Unconsolidated Joint Venture Multi-Family Properties [Member] | Marbella Tower Urban Renewal Associates LLC [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item   311        
Company's Effective Ownership %     24.27%      
Balance   $ 117,000 $ 74,700      
Property Debt, Maturity Date       Aug. 01, 2026    
Property Debt, Interest Rate, Spread Over LIBOR   4.20%        
Percentage of additional interest acquired   50.00% 50.00%      
Repayment of mortgage loans   $ 74,700        
Purchase price of property   $ 77,500        
Unconsolidated Joint Venture Multi-Family Properties [Member] | Metropolitan At 40 Park [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       189    
Company's Effective Ownership %       25.00%    
Carrying Value       $ 7,481   7,679
Balance       $ 54,802    
Unconsolidated Joint Venture Multi-Family Properties [Member] | RiverTrace At Port Imperial [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       316    
Company's Effective Ownership %       22.50%    
Carrying Value       $ 7,732   8,112
Balance       $ 82,000    
Property Debt, Maturity Date       Nov. 10, 2026    
Property Debt, Interest Rate       3.21%    
Unconsolidated Joint Venture Multi-Family Properties [Member] | Crystal House [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       825    
Company's Effective Ownership %       25.00%    
Carrying Value       $ 28,738   29,570
Balance       $ 161,171    
Property Debt, Maturity Date       Apr. 01, 2020    
Property Debt, Interest Rate       3.17%    
Unconsolidated Joint Venture Multi-Family Properties [Member] | PI North - Riverwalk C [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       360    
Company's Effective Ownership %       40.00%    
Carrying Value       $ 35,314   27,175
Balance       $ 6,051    
Property Debt, Maturity Date       Dec. 06, 2021    
Property Debt, Interest Rate       2.75%    
Unconsolidated Joint Venture Multi-Family Properties [Member] | Marbella II [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       311    
Company's Effective Ownership %       24.27%    
Carrying Value           15,414
Unconsolidated Joint Venture Multi-Family Properties [Member] | Riverpark At Harrison [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       141    
Company's Effective Ownership %       45.00%    
Carrying Value       $ 1,075   1,272
Balance       $ 29,541    
Property Debt, Maturity Date       Aug. 01, 2025    
Property Debt, Interest Rate       3.70%    
Unconsolidated Joint Venture Multi-Family Properties [Member] | Station House [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       378    
Company's Effective Ownership %       50.00%    
Carrying Value       $ 36,581   37,675
Balance       $ 97,692    
Property Debt, Maturity Date       Jul. 01, 2033    
Property Debt, Interest Rate       4.82%    
Unconsolidated Joint Venture Multi-Family Properties [Member] | Urby At Harborside [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       762    
Company's Effective Ownership %       85.00%    
Carrying Value       $ 82,018   85,317
Balance       $ 192,000    
Property Debt, Maturity Date       Aug. 01, 2029    
Property Debt, Interest Rate       5.197%    
Unconsolidated Joint Venture Multi-Family Properties [Member] | PI North - Land [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       836    
Company's Effective Ownership %       20.00%    
Carrying Value       $ 1,678   1,678
Unconsolidated Joint Venture Multi-Family Properties [Member] | Liberty Landing [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       850    
Company's Effective Ownership %       50.00%    
Carrying Value       $ 337   337
Unconsolidated Joint Venture Multi-Family Properties [Member] | Hillsborough 206 [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       160,000    
Company's Effective Ownership %       50.00%    
Carrying Value       $ 1,962   1,962
Unconsolidated Joint Venture Office Buildings [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       200,000    
Unconsolidated Joint Venture Office Buildings [Member] | Red Bank [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       92,878    
Company's Effective Ownership %       50.00%    
Carrying Value           3,127
Gain on sale $ 900          
Unconsolidated Joint Venture Office Buildings [Member] | 12 Vreeland Road [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       139,750    
Company's Effective Ownership %       50.00%    
Carrying Value       $ 7,176   7,019
Balance       $ 7,091    
Property Debt, Maturity Date       Jul. 01, 2023    
Property Debt, Interest Rate       2.87%    
Unconsolidated Joint Venture Office Buildings [Member] | Offices At Crystal Lake [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       106,345    
Company's Effective Ownership %       31.25%    
Carrying Value       $ 3,471   3,442
Balance       $ 3,703    
Property Debt, Maturity Date       Nov. 01, 2023    
Property Debt, Interest Rate       4.76%    
Unconsolidated Joint Venture Other Property [Member]            
Schedule of Equity Method Investments [Line Items]            
Carrying Value       $ 215,957   232,750
Balance       $ 734,051    
Unconsolidated Joint Venture Other Property [Member] | Riverwalk Retail [Member]            
Schedule of Equity Method Investments [Line Items]            
Rentable Square Feet (sf) | ft²       30,745    
Company's Effective Ownership %       20.00%    
Carrying Value       $ 1,497   1,539
Unconsolidated Joint Venture Other Property [Member] | Hyatt Regency Jersey City [Member]            
Schedule of Equity Method Investments [Line Items]            
Number of Apartment Units | item       351    
Company's Effective Ownership %       50.00%    
Carrying Value         112
Balance       $ 100,000    
Property Debt, Maturity Date       Oct. 01, 2026    
Property Debt, Interest Rate       3.668%    
Unconsolidated Joint Venture Other Property [Member] | Other [Member]            
Schedule of Equity Method Investments [Line Items]            
Carrying Value       $ 897   $ 1,320