Recent Transactions (Schedule Of Properties Which Commenced Initial Operations) (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
USD ($)
item
Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 3,587
Quarry Place At Tuckahoe [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 108
Development Costs Incurred by Company $ 56,961 [1]
The Chase At Overlook Ridge [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 292
Development Costs Incurred by Company $ 65,218 [2]
Quarry Place At Tuckahoe And The Chase At Overlook Ridge [Member] | Unconsolidated Joint Venture Multi-Family Properties [Member]  
Real Estate Properties [Line Items]  
Number of Apartment Units | item 400
Development Costs Incurred by Company $ 122,179
Land [Member] | Quarry Place At Tuckahoe [Member]  
Real Estate Properties [Line Items]  
Development Costs Incurred by Company 5,600
Land [Member] | The Chase At Overlook Ridge [Member]  
Real Estate Properties [Line Items]  
Development Costs Incurred by Company 10,800
Construction Loan [Member] | The Chase At Overlook Ridge [Member]  
Real Estate Properties [Line Items]  
Expected costs $ 9,700
[1] Development costs as of December 31, 2016 included approximately $5.6 million in land costs.
[2] Development costs as of December 31, 2016 included approximately $10.8 million in land costs. As of December 31, 2016, the Company anticipates additional costs of approximately $9.7 million, which will be funded from a construction loan.