RELATED PARTY TRANSACTIONS - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Ratio of percentage of stockholders' equity			0.000875
Compensation and management fee	$ 45,579	$ 38,938	$ 90,108	$ 78,200
Ratio of independent directors or holders of a majority of the outstanding shares			0.0066666667
Management Agreement
Related Party Transaction [Line Items]
Compensation and management fee	45,600	$ 38,900	$ 90,100	$ 78,200
Management fee payable	$ 14,700		$ 14,700		$ 13,800
Renewal term			2 years
Accelerated period for agreement termination, if election to terminate is not made			90 days
Management Agreement | Minimum
Related Party Transaction [Line Items]
Management agreement, required period to terminate from the date of the notice			1 year
Accelerated period for agreement termination, if election to terminate is made			7 days
Management Agreement | Maximum
Related Party Transaction [Line Items]
Accelerated period for agreement termination, if election to terminate is made			90 days