Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 216,199	$ 147,335	$ 107,896
Other comprehensive income (loss):
Fair value of interest rate swaps, net of tax			3,957
Foreign currency translation adjustment gain (loss), net of tax	10,370	(5,615)	115
Total other comprehensive income (loss)	10,370	(5,615)	4,072
Total comprehensive income	$ 226,569	$ 141,720	$ 111,968