Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 73,099	$ 54,401	$ 137,761	$ 96,480
Other comprehensive income:
Foreign currency translation adjustment loss, net of tax	(23,422)	(9,197)	(34,154)	(125)
Total other comprehensive loss	(23,422)	(9,197)	(34,154)	(125)
Total comprehensive income	$ 49,677	$ 45,204	$ 103,607	$ 96,355