CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 11,513	$ 16,111	$ 26,446	$ 45,190
Other comprehensive income, net of tax:
Foreign currency translation adjustments, net of $0 tax in the three and nine months ended September 30, 2015 and 2014 (Note 2)	40	(53)	18	(42)
Unrealized gain (loss) on marketable securities, net of $0 tax in the three and nine months ended September 30, 2015 and 2014 (Note 2)	20	(246)	(17)	(7)
Amortization of defined benefit pension items, net of tax of $18 and $26 in the three and nine months ended September 30, 2015, respectively and $4 and $12 in the three and nine months ended September 30, 2014, respectively (Note 2)	64	15	92	45
Total other comprehensive income (loss)	124	(284)	93	(4)
TOTAL COMPREHENSIVE INCOME	$ 11,637	$ 15,827	$ 26,539	$ 45,186