COMMITMENTS AND CONTINGENCIES (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Long Term Purchase Commitment [Line Items]
Total rent expense	$ 2,185	$ 2,185	$ 2,304
Purchase obligations	$ 39,756
Minimum [Member]
Long Term Purchase Commitment [Line Items]
Lease obligations, term (in Duration)	1 year
Maximum [Member]
Long Term Purchase Commitment [Line Items]
Lease obligations, term (in Duration)	12 years
Maximum term of supply agreements with various food vendors (in Duration)	5 years