COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in accumulated other comprehensive income (loss) by component
Balance	$ 290,105
Balance	260,032
Unrealized Gain (Loss) on Marketable Securities
Changes in accumulated other comprehensive income (loss) by component
Balance	(289)	$ 9
Other comprehensive income before reclassifications	380	11
Net current-period other comprehensive income	380	11
Balance	91	20
Foreign Currency Items
Changes in accumulated other comprehensive income (loss) by component
Balance	2,596	2,581
Other comprehensive income before reclassifications		15
Net current-period other comprehensive income		15
Balance	2,596	2,596
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income (loss) by component
Balance	2,307	2,590
Other comprehensive income before reclassifications	380	26
Amounts reclassified out of accumulated other comprehensive income	0	0
Net current-period other comprehensive income	380	26
Balance	$ 2,687	$ 2,616