FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and cash equivalents	$ 44,958	$ 28,255	$ 32,774	$ 16,293
Foreign currency forward contracts	465	258
Recurring | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and cash equivalents	44,958	28,255
Cash and cash equivalents, fair value	44,958	28,255
Restricted cash	2,717	2,923
Restricted cash, fair value	2,717	2,923
Recurring | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Foreign currency forward contracts	583	308
Variable interest rate debt	0	5,986
Variable interest rate debt, fair value	0	5,986
Foreign currency forward contracts	$ 1,048	$ 566