INCOME TAXES (Reconciliation of Income Tax Uncertainties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance [Line Items]
Valuation allowance	$ 5,414	$ 4,070
Reconciliation of the beginning and ending amount of income tax uncertainties
Balance at the beginning of period	6,356	7,934	$ 6,408
Increases based on tax positions for the current year	370	270	255
Increases based on tax positions of prior years	1,562	1,283	2,684
Decreases based on tax positions of prior years	0	(1,472)	(518)
Settlements	(4,874)	(1,444)	(207)
Lapse of statute of limitations	(334)	(215)	(688)
Balance at the end of period	3,080	6,356	7,934
Foreign taxes payable in the event of non-fulfillment of terms of government grants	1,700
Amount of income tax uncertainties that, if recognized, would impact the effective tax rate	3,100
Decrease in liability for uncertain tax positions, high end of range	1,400
Unrecognized tax benefits, amount accrued for the payment of interest and penalties	1,600	1,500	1,100
Unrecognized tax benefits, amount recognized in income tax expense	100	$ 400	$ 400
Deferred tax assets related to tax credit carryforwards, U.S. state
Valuation Allowance [Line Items]
Valuation allowance	2,700
Deferred tax assets for specified locations
Valuation Allowance [Line Items]
Valuation allowance	$ 2,700