Condensed Consolidated Statements of Comprehensive Operations (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 58,310	$ 87,571
Other comprehensive income, net of income tax:
Interest rate lock derivative contracts reclassified to income, net of tax of $13 and $8, respectively	15	20
Total other comprehensive income	15	20
Comprehensive income	$ 58,325	$ 87,591