Quarterly report pursuant to Section 13 or 15(d)

Recent Transactions (Schedule Of Properties Which Commenced Initial Operations) (Details)

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Recent Transactions (Schedule Of Properties Which Commenced Initial Operations) (Details)
$ in Thousands
 9 Months Ended
Sep. 30, 2018
USD ($)
item
Real Estate Properties [Line Items]  
Number of Apartment Units | item 1,153
Total Development Costs $ 396,056
Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 2,922
145 Front At City Square [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 365
Total Development Costs $ 97,172
Signature Place At Morris Plains [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 197
Total Development Costs $ 56,643
Portside 5/6 [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 296
Total Development Costs $ 114,723
Riverhouse 11 At Port Imperial [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 295
Total Development Costs $ 127,518
Expected costs 8,200
Riverhouse 11 At Port Imperial [Member] | Cash [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Expected costs 2,700
Land [Member] | 145 Front At City Square [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Total Development Costs 4,400
Land [Member] | Signature Place At Morris Plains [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Total Development Costs 900
Construction Loan [Member] | 145 Front At City Square [Member]  
Real Estate Properties [Line Items]  
Expected costs 3,500
Construction Loan [Member] | Signature Place At Morris Plains [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Expected costs 200
Construction Loan [Member] | Portside 5/6 [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Expected costs 3,300
Construction Loan [Member] | Riverhouse 11 At Port Imperial [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Expected costs $ 5,500