CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net income	$ 12,363	$ 10,903
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in the quarters ended March 31, 2014 and 2013 (Note 2)	(6)	(151)
Unrealized gain (loss) on marketable securities, net of $0 tax in the quarters ended March 31, 2014 and 2013 (Note 2)	147	(54)
Amortization of defined benefit pension items, net of tax of $4 and $4 in the quarters ended March 31, 2014 and 2013, respectively (Note 2)	14	14
Total other comprehensive income (loss)	155	(191)
Total comprehensive income	$ 12,518	$ 10,712