Real Estate Transactions (Narrative) (Details) (USD $)
3 Months Ended 12 Months Ended 0 Months Ended
Mar. 31, 2015
property
Mar. 31, 2014
Dec. 31, 2014
property
Apr. 01, 2015
Real Estate Properties [Line Items]        
Purchase price of property $ 19,658,000 $ 14,600,000    
Realized gains (losses) on disposition of rental property, net 144,000      
Number of properties sold 1   16  
City Square Project [Member] | Subsequent Event [Member]        
Real Estate Properties [Line Items]        
Number of units       370
Purchase price of property       3,100,000
Contingent consideration       1,250,000
Minimum project start period       12 months
Total project costs       88,000,000
1451 Metropolitan Drive [Member]        
Real Estate Properties [Line Items]        
Area of property (in square feet) 21,600      
Sales proceeds $ 1,100,000