INVESTMENT IN HOTEL PROPERTIES - Summary of hotel properties acquisitions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Room	Dec. 31, 2016 USD ($) Room
Business Acquisition [Line Items]
Number of guestrooms | Room	2,442	749
Purchase Price	$ 585,950	$ 244,150
Net assets acquired	588,822	244,714
Settlement amount of net working capital assets	200	$ 600
Capitalized transaction costs	$ 2,600
Homewood Suites | Aliso Viejo (Laguna Beach), CA
Business Acquisition [Line Items]
Number of guestrooms | Room	129
Purchase Price	$ 38,000
Homewood Suites | Tucson, AZ
Business Acquisition [Line Items]
Number of guestrooms | Room	122
Purchase Price	$ 25,300
Hyatt Place | Phoenix (Mesa), AZ
Business Acquisition [Line Items]
Number of guestrooms | Room	152
Purchase Price	$ 22,200
Hyatt Place | Chicago, IL
Business Acquisition [Line Items]
Number of guestrooms | Room		206
Purchase Price		$ 73,750
Courtyard by Marriott | Fort Lauderdale, FL
Business Acquisition [Line Items]
Number of guestrooms | Room	261
Purchase Price	$ 85,000
Courtyard by Marriott | Charlotte, NC
Business Acquisition [Line Items]
Number of guestrooms | Room	181
Purchase Price	$ 56,250
Courtyard by Marriott | Fort Worth, TX
Business Acquisition [Line Items]
Number of guestrooms | Room	203
Purchase Price	$ 40,000
Courtyard by Marriott | Kansas City, MO
Business Acquisition [Line Items]
Number of guestrooms | Room	123
Purchase Price	$ 24,500
Courtyard by Marriott | Pittsburgh, PA
Business Acquisition [Line Items]
Number of guestrooms | Room	182
Purchase Price	$ 42,000
Courtyard by Marriott | Nashville, TN
Business Acquisition [Line Items]
Number of guestrooms | Room		226
Purchase Price		$ 71,000
Courtyard by Marriott | New Haven, CT
Business Acquisition [Line Items]
Number of guestrooms | Room	207
Purchase Price	$ 63,400
Hilton Garden Inn | Waltham, MA
Business Acquisition [Line Items]
Number of guestrooms | Room	148
Purchase Price	$ 32,300
Hampton Inn & Suites | Baltimore, MD
Business Acquisition [Line Items]
Number of guestrooms | Room	116
Purchase Price	$ 18,000
Residence Inn | Baltimore, MD
Business Acquisition [Line Items]
Number of guestrooms | Room	188
Purchase Price	$ 38,500
Residence Inn | Atlanta, GA
Business Acquisition [Line Items]
Number of guestrooms | Room		160
Purchase Price		$ 38,000
Residence Inn | Cleveland, OH
Business Acquisition [Line Items]
Number of guestrooms | Room	175
Purchase Price	$ 43,000
AC Hotel by Marriott | Atlanta, GA
Business Acquisition [Line Items]
Number of guestrooms | Room	255
Purchase Price	$ 57,500
Marriott | Boulder, CO
Business Acquisition [Line Items]
Number of guestrooms | Room		157
Purchase Price		$ 61,400