EQUITY - Changes in common stock (Details) - shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in Common Stock [Roll Forward]
Beginning common shares outstanding	86,793,521	86,149,720
Common Unit redemptions	31,042	20,691
Grants under the Equity Plan	446,280	303,915
Common stock for director fees	2,062
Forfeitures		(46,030)
Other	(53,059)	(36,116)
Ending common shares outstanding	87,219,846	86,392,180