SUBSEQUENT EVENTS (Details) $ / shares in Units, $ in Thousands		6 Months Ended	12 Months Ended
	Jul. 30, 2018 $ / shares	Jun. 30, 2018 hotel	Dec. 31, 2017	Jul. 24, 2018 USD ($) hotel	Apr. 30, 2017 USD ($) hotel
Subsequent events
Number of hotels | hotel		80
6.45% Series D Preferred Stock
Subsequent events
Preferred stock, dividend rate		6.45%	6.45%
6.25% Series E Preferred Stock
Subsequent events
Preferred stock, dividend rate		6.25%	6.25%
Subsequent Event
Subsequent events
Cash dividends declared, common stock (in dollars per share) | $ / shares	$ 0.18
Subsequent Event | 6.45% Series D Preferred Stock
Subsequent events
Cash dividends declared, preferred stock (in dollars per share) | $ / shares	0.403125
Subsequent Event | 6.25% Series E Preferred Stock
Subsequent events
Cash dividends declared, preferred stock (in dollars per share) | $ / shares	$ 0.390625
Disposed of by Sale
Subsequent events
Number of hotels | hotel					23
Aggregate sales price | $					$ 325,100
Disposed of by Sale | Subsequent Event
Subsequent events
Number of hotels | hotel				3
Aggregate sales price | $				$ 46,500