Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 75,109	$ 64,662
Other comprehensive income:
Foreign currency translation adjustment gain (loss), net of tax of $0 for each period	15,927	(10,732)
Total other comprehensive income (loss)	15,927	(10,732)
Total comprehensive income	$ 91,036	$ 53,930