Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Components of the provision for income taxes
Federal	$ (7,439)	$ 0
State	(3,842)	(164)
Deferred portion of income tax (expense) benefit	(33,225)	195,039
Income tax (expense) benefit	$ (44,506)	$ 194,875
Effective tax rate	37.40%	35.90%

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