Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 50,458	$ 47,305	$ 148,737	$ 135,795
Other comprehensive (loss) income, net of tax	(5,924)	6,198	12,630	(26,675)
Comprehensive income	$ 44,534	$ 53,503	$ 161,367	$ 109,120