CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other comprehensive income (loss):
Currency translation adjustment, tax	$ (111)	$ 0	$ (456)	$ (194)
Unrealized gain on marketable securities arising during the period, tax	15	(54)	74	(39)
Change in unfunded SERP liability, tax	$ 32	$ 28	$ 136	$ 84