Commitments And Contingencies (Construction Projects) (Narrative) (Details)
 3 Months Ended 12 Months Ended
Oct. 06, 2015
USD ($)
item
Apr. 01, 2015
USD ($)
Mar. 31, 2016
USD ($)
item
Mar. 31, 2015
USD ($)
Mar. 31, 2016
USD ($)
item
Dec. 31, 2015
USD ($)
Sep. 30, 2015
item
Commitments And Contingencies [Line Items]              
Amount outstanding     $ 90,000,000   $ 90,000,000 $ 155,000,000  
Investment in unconsolidated joint ventures     7,225,000 $ 20,880,000      
Development of rental property     16,131,000 12,519,000      
Purchase price of property     $ 34,603,000 $ 19,658,000      
Eastchester Project [Member]              
Commitments And Contingencies [Line Items]              
Percentage of interest in venture     76.25%   76.25%    
Costs of the project incurred     $ 16,100,000        
Delivery date to tenant     second quarter of 2016        
Number of units | item     108   108    
Project costs incurred to date     $ 35,900,000   $ 35,900,000    
Amount of project costs funded by members     20,900,000   20,900,000    
Total project costs     50,000,000        
Amount to fund     4,800,000   4,800,000    
City Square Project [Member]              
Commitments And Contingencies [Line Items]              
Costs of the project incurred         10,600,000    
Total project costs     92,500,000        
Purchase price of property   $ 3,100,000          
Contingent consideration   $ 1,250,000          
Amount to fund     40,400,000   $ 40,400,000    
City Square Project Phase One [Member]              
Commitments And Contingencies [Line Items]              
Number of units | item             237
Signature Place Project [Member]              
Commitments And Contingencies [Line Items]              
Costs of the project incurred     $ 4,700,000        
Number of units | item     197   197    
Project costs incurred to date     $ 5,100,000   $ 5,100,000    
Total project costs     61,400,000        
Amount to fund     $ 19,400,000   $ 19,400,000    
Portside 5/6 Project [Member]              
Commitments And Contingencies [Line Items]              
Percentage of interest in venture     85.00%   85.00%    
Costs of the project incurred     $ 6,200,000        
Number of units | item     296   296    
Project costs incurred to date     $ 8,500,000   $ 8,500,000    
Total project costs     112,400,000        
Construction Loan [Member] | City Square Project [Member]              
Commitments And Contingencies [Line Items]              
Maximum borrowing capacity     41,500,000   41,500,000    
Amount outstanding     0   0    
Construction Loan [Member] | Signature Place Project [Member]              
Commitments And Contingencies [Line Items]              
Amount to fund     42,000,000   42,000,000    
150 Main Street, L.L.C. [Member] | Construction Loan [Member] | Eastchester Project [Member]              
Commitments And Contingencies [Line Items]              
Maximum borrowing capacity     28,800,000   28,800,000    
Amount outstanding     16,100,000   16,100,000    
Development Property [Member] | Portside 5/6 Project [Member]              
Commitments And Contingencies [Line Items]              
Amount to fund     33,500,000   $ 33,500,000    
Development Property [Member] | Chase II Project [Member]              
Commitments And Contingencies [Line Items]              
Costs of the project incurred     $ 26,400,000        
Number of units | item     1,034   1,034    
Total project costs     $ 74,900,000        
Amount to fund     $ 500,000   $ 500,000    
Development Property [Member] | Chase II Project, Initial Phase [Member]              
Commitments And Contingencies [Line Items]              
Number of units | item     292   292    
Development Property [Member] | Construction Loan [Member] | Chase II Project [Member]              
Commitments And Contingencies [Line Items]              
Maximum borrowing capacity     $ 48,000,000   $ 48,000,000    
Amount outstanding     0   $ 0    
Unconsolidated Joint Venture Hotel [Member]              
Commitments And Contingencies [Line Items]              
Percentage of interest in venture 90.00%            
Development costs     $ 4,700,000        
Number of units | item     350   350    
Amount to fund     $ 500,000   $ 500,000    
Unconsolidated Joint Venture Hotel [Member] | XS Port Imperial Hotel, LLC [Member]              
Commitments And Contingencies [Line Items]              
Number of units | item 364            
Ownership percentage of third party venture 10.00%            
Unconsolidated Joint Venture Hotel [Member] | Port Imperial Hotel [Member]              
Commitments And Contingencies [Line Items]              
Total project costs $ 105,900,000            
Unconsolidated Joint Venture Hotel [Member] | Construction Loan [Member] | Portside 5/6 Project [Member]              
Commitments And Contingencies [Line Items]              
Amount to fund     73,000,000   73,000,000    
Unconsolidated Joint Venture Hotel [Member] | Construction Loan [Member] | Port Imperial Hotel [Member]              
Commitments And Contingencies [Line Items]              
Amount outstanding     $ 0   $ 0    
Amount to fund $ 94,000,000