ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ACCRUED EXPENSES [Abstract]
Accrued compensation and benefits	$ 3,114	$ 7,571
Accrued rent and real estate taxes	3,151	3,365
Other accrued expenses	5,506	4,432
Accrued expenses	$ 11,771	$ 15,368