CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 174,560	$ 304,442	$ 217,868
Other comprehensive gain (loss):
Foreign currency translation (loss) gain	(1,193)	691	(1,709)
Defined benefit pension plan:
Prior service cost arising during period, net of tax			(1,010)
Actuarial gain (loss) arising during period, net of tax	2,075	(5,352)	431
Less: amortization of actuarial gain and prior service cost included in net periodic pension cost	1,020	522	572
Defined benefit pension plan, net	3,095	(4,830)	(7)
Unrealized (loss) gain on available-for-sale securities, net of tax	(128)	67	6
Other comprehensive gain (loss), net of tax	1,774	(4,072)	(1,710)
Comprehensive income	$ 176,334	$ 300,370	$ 216,158