Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Components of the provision for income taxes
Federal	$ 0	$ 0
State	(965)	(625)
Deferred portion of income tax (expense) benefit	47,003	(98,366)
Income tax (expense) benefit	$ 46,038	$ (98,991)
Effective tax rate	20.60%	23.80%

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