Net Loss on Disposition of Partial Interest in Development Project (Details Textuals) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Greenland Joint Venture [Member]	Jun. 30, 2013 Greenland Joint Venture [Member]	Jun. 30, 2013 Pacific Park Brooklyn [Member] Greenland Joint Venture [Member] acre
Significant Acquisitions and Disposals [Line Items]
Area of project (in acres)							22
Percentage of ownership sold						70.00%
Cash purchase price received, net of transaction costs					$ 203,923,000
Net loss on disposition of partial interest in development project	0	0	19,590,000	0	19,590,000
Net loss on disposition of partial interest in development project, net of noncontrolling interests					$ 16,211,000