ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive loss [Abstract]
Foreign currency translation adjustment		$ (28,976)	$ (19,305)	$ (9,351)
Unrealized holding gain on available-for-sale securities, net of taxes of $263, $265 and $259 as of December 31, 2016, 2015 and 2014		424	434	429
Unfunded SERP liability, net of taxes of ($1,398), ($1,327) and ($1,325) as of December 31, 2016, 2015 and 2014		(2,745)	(3,005)	(3,026)
Accumulated other comprehensive loss		(31,297)	(21,876)	(11,948)
Accumulated other comprehensive loss, tax [Abstract]
Unrealized holding gains on available-for-sale securities, tax		263	265	259
Change in unfunded SERP liability, tax		(1,398)	(1,327)	(1,325)
Changes in Accumulated Other Comprehensive (Loss) Income by Component [Roll Forward]
Balance		233,122	224,273	228,702
Other comprehensive income (loss) before reclassifications		(9,676)	(10,182)
Amounts reclassified from accumulated other comprehensive income (loss)		255	254
Net current period other comprehensive income (loss)		(9,421)	(9,928)	(12,593)
Balance		158,434	233,122	224,273
AOCI Attributable to Parent [Member]
Changes in Accumulated Other Comprehensive (Loss) Income by Component [Roll Forward]
Balance		(21,876)	(11,948)	645
Balance		(31,297)	(21,876)	(11,948)
Foreign Currency Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive (Loss) Income by Component [Roll Forward]
Balance		(19,305)	(9,351)
Other comprehensive income (loss) before reclassifications		(9,671)	(9,954)
Amounts reclassified from accumulated other comprehensive income (loss)		0	0
Net current period other comprehensive income (loss)		(9,671)	(9,954)
Balance		(28,976)	(19,305)	(9,351)
Unrealized Holding Gains on Available-for-Sale Securities [Member]
Changes in Accumulated Other Comprehensive (Loss) Income by Component [Roll Forward]
Balance		434	429
Other comprehensive income (loss) before reclassifications		(10)	5
Amounts reclassified from accumulated other comprehensive income (loss)		0	0
Net current period other comprehensive income (loss)		(10)	5
Balance		424	434	429
Unfunded SERP Liability [Member]
Changes in Accumulated Other Comprehensive (Loss) Income by Component [Roll Forward]
Balance		(3,005)	(3,026)
Other comprehensive income (loss) before reclassifications		5	(233)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	255	254
Net current period other comprehensive income (loss)		260	21
Balance		$ (2,745)	$ (3,005)	$ (3,026)

[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.