ACQUISITION AND DISPOSITION OF REAL ESTATE AND PROPERTIES HELD FOR SALE - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
ACQUISITION AND DISPOSITION OF REAL ESTATE AND DISCONTINUED OPERATIONS ABSTRACT
Total revenues	$ 171,224	$ 182,413
Operating and other expenses	(126,512)	(129,702)
Interest and other finance expense	(25,485)	(29,948)
Net income	105,069	146,638
Net income attributable to Common Shareholders	$ 57,436	$ 61,088
Basic and diluted earnings per Common Share attributable to Common Shareholders (in dollars per share)	$ 0.70	$ 0.79