CONSOLIDATED STATEMENTS OF OTHER COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CONSOLIDATED STATEMENTS OF OTHER COMPREHENSIVE INCOME
Net income	$ 23,527	$ 22,117
Other comprehensive income (loss), net of tax:
Amortization of actuarial loss on defined benefit pension plan, net	5	0
Unrealized gain (loss) on marketable securities, available-for-sale, net	188	(124)
Other comprehensive income (loss), net of tax	193	(124)
Comprehensive income	$ 23,720	$ 21,993