Significant Accounting Policy (Details) ft² in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($) ft² aptunits	Dec. 31, 2014 USD ($)
Real Estate Properties [Line Items]
Development and construction in progress	$ 105,544,000	$ 75,289,000
Rego Park II [Member] | Apartment Tower [Member] | Property Under Development [Member]
Real Estate Properties [Line Items]
Number of units in apartment tower (in units) | aptunits	312
Area of property (in square feet) | ft²	255
Estimated Budgeted Cost	$ 125,000,000
Development and construction in progress	$ 103,307,000
Estimated Date Of Completion	2015