ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
ACCRUED EXPENSES [Abstract]
Sales commissions	$ 2,321		$ 2,461
Subcontracting labor	1,221		1,408
Salaries, bonuses and related benefits	14,097		16,531
Warranty accrual	1,606		1,769
Other	8,164		8,339
Accrued expenses	27,409		$ 30,508
Warranty Accrual Activity Account [Roll Forward]
Balance	1,769	$ 2,718
Adjustments related to pre-existing warranties (including changes in estimates)	(143)	(158)
Less repair costs incurred	(61)	(50)
Currency translation	41	30
Balance	$ 1,606	$ 2,540