CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 8,843	$ 6,343
Other comprehensive income, net of tax:
Foreign currency translation adjustments, net of $0 tax in each of the three months ended March 31, 2016 and 2015	(54)	35
Unrealized gain on marketable securities, net of $0 tax in each of the three months ended March 31, 2016 and 2015	213	56
Amortization of defined benefit pension items, net of tax of $11 and $4 in the three months ended March 31, 2016 and 2015, respectively	40	14
Total other comprehensive income	199	105
TOTAL COMPREHENSIVE INCOME	$ 9,042	$ 6,448