Income Taxes (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income tax provision
State income tax	$ 371	$ 0	$ 0
Federal alternative minimum tax	2,588	133	404
Net current income tax provision	2,959	133	404
Deferred income tax provision (benefit)
Federal tax expense at statutory rate	(289,412)	61,301	19,177
State income tax	(13,215)	2,707	431
Permanent differences	698	397	319
Federal alternative minimum tax	(2,588)	(133)	(404)
Change in federal valuation allowance	145,777	0	(8,885)
Change in state valuation allowance	8,413	(30)	(1,345)
Net deferred income tax (benefit) provision	(150,327)	64,242	9,293
Total income tax (benefit) provision	$ (147,368)	$ 64,375	$ 9,697
Federal statutory rate	35.00%	35.00%	35.00%