Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Components of the provision for income taxes
Federal	$ 0	$ 0	$ 0	$ 0
State	10,126	512	10,400	1,001
Deferred portion of income tax expense	(50,829)	35,537	(84,556)	73,911
Income tax expense	$ (40,703)	$ 36,049	$ (74,156)	$ 74,912
Effective tax rate	41.40%	37.60%	40.10%	37.40%