Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 64,662	$ 42,079
Other comprehensive income:
Foreign currency translation adjustment (loss) gain, net of tax of $0 at each date	(10,732)	9,072
Total other comprehensive income	(10,732)	9,072
Total comprehensive income	$ 53,930	$ 51,151