FAIR VALUE MEASUREMENT - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) Loan hotel
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of hotels | hotel	83
Mezzanine Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of construction loans | Loan	3
Net amount of loan receivable	$ 29.6
Number of hotels | hotel	3
Interest rate	8.00%
Loans initial term	3 years
Funded amount of loan receivable	$ 23.3
Interest in hotel upon completion to purchase	90.00%
Period of time after initial option exercise to purchase remaining interests	5 years
Amortization of discount	$ 0.5
Other Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchase options related to real estate loans	$ 6.1