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	$ 88,711	$ 69,447	$ 50,546
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) on hedging derivatives, net of taxes of $382, $104, and $3 for the years ended December 31, 2013, 2012 and 2011, respectively	565	137	(7)
Reclassification of net loss on interest rate corridor, net of taxes of $70 for the year ended December 31, 2011			92
Unrealized gains on available for sale securities, net of taxes of $11 for the year ended December 31, 2013	16
Comprehensive income	$ 89,292	$ 69,584	$ 50,631