ACCUMULATED OTHER COMPREHENSIVE LOSS, Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Balance		$ 157,960
Other comprehensive income before reclassifications		4,000
Amount reclassified from accumulated other comprehensive loss		72
Net current period other comprehensive income		4,072	$ 1,693
Balance		164,175
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Balance		(19,625)
Balance		(15,553)
Foreign Currency Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Balance		(16,537)
Other comprehensive income before reclassifications		4,017
Amount reclassified from accumulated other comprehensive loss		0
Net current period other comprehensive income		4,017
Balance		(12,520)
Unrealized Holding Gains on Available-for-Sale Securities [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Balance		145
Other comprehensive income before reclassifications		(31)
Amount reclassified from accumulated other comprehensive loss		0
Net current period other comprehensive income		(31)
Balance		114
Unfunded SERP Liability [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Balance		(3,233)
Other comprehensive income before reclassifications		14
Amount reclassified from accumulated other comprehensive loss	[1]	72
Net current period other comprehensive income		86
Balance		$ (3,147)

[1] This reclassification relates to the amortization of prior service costs and gains/losses associated with the Company's SERP plan. This expense is allocated between cost of sales and selling, general and administrative expense based upon the employment classification of the plan participants.