Condensed Consolidated Statements of Comprehensive Operations (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	$ 268,748	$ 102,054	$ 271,858	$ 319,605
Other comprehensive income, net of income tax:
Interest rate lock derivative contracts reclassified to income, net of tax of $11, $11, $35 and $30, respectively	18	17	50	54
Total other comprehensive income	18	17	50	54
Comprehensive income	$ 268,766	$ 102,071	$ 271,908	$ 319,659