SUBSEQUENT EVENTS (Details) - $ / shares			3 Months Ended	12 Months Ended
	Apr. 29, 2016	Apr. 01, 2016	Mar. 31, 2016	Dec. 31, 2015
Subsequent Event
Subsequent events
Cash dividends declared, common stock (in dollars per share)	$ 0.1325
Subsequent Event | Non-controlling Interests in Operating Partnership | Operating partnership | Common units
Subsequent events
Common units redeemed		22,594
9.25% Series A Preferred Stock
Subsequent events
Preferred stock, dividend rate (as a percent)			9.25%	9.25%
9.25% Series A Preferred Stock | Subsequent Event
Subsequent events
Cash dividends declared, preferred stock (in dollars per share)	0.578125
7.875% Series B Preferred Stock
Subsequent events
Preferred stock, dividend rate (as a percent)			7.875%	7.875%
7.875% Series B Preferred Stock | Subsequent Event
Subsequent events
Cash dividends declared, preferred stock (in dollars per share)	0.4921875
7.125% Series C Preferred Stock
Subsequent events
Preferred stock, dividend rate (as a percent)			7.125%	7.125%
7.125% Series C Preferred Stock | Subsequent Event
Subsequent events
Cash dividends declared, preferred stock (in dollars per share)	$ 0.4453125