SUBSEQUENT EVENTS (Details) $ / shares in Units, $ in Thousands					3 Months Ended		12 Months Ended
	Apr. 29, 2019 $ / shares	Apr. 24, 2019 USD ($)	Apr. 17, 2019 USD ($) hotel	Apr. 11, 2019 USD ($)	Mar. 31, 2019 USD ($) hotel	Mar. 31, 2018 USD ($)	Dec. 31, 2018	Mar. 19, 2019 USD ($)
Subsequent events
Number of hotels | hotel					75
Repayments of debt					$ 42,326	$ 162,034
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
Six properties sold on April 17, 2019 | Disposed of by Sale | Subsequent Event
Subsequent events
Number of hotels | hotel			6
Aggregate sales price			$ 135,000
Aggregate sale price, net			133,000
Buyer credit on disposal			2,000
Net gain on sale of properties			$ 36,600
Mortgage loans
Subsequent events
Debt transaction costs								$ 600
U.S. Bank | Mortgage loans | Subsequent Event
Subsequent events
Repayments of debt				$ 10,600
Debt transaction costs				$ 1,000
Compass Bank | Mortgage loans | Subsequent Event
Subsequent events
Repayments of debt		$ 21,900