CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 134,358	$ 122,904	$ 174,643
Other comprehensive income (loss):
Unrealized gain (loss) on hedging transactions, net of income taxes	118	(7,241)	6,209
Unrealized holding gain (loss) on investments, net of income taxes	(456)	887	(385)
Foreign currency translation adjustment	882	242	(688)
Comprehensive income	$ 134,902	$ 116,792	$ 179,779