Supplemental Disclosures (Details 1) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Supplemental disclosures of cash flow information
Cash paid for interest expense, net of amounts capitalized	$ 12,226	$ 2,263
Asset retirement obligations related to mineral properties	2,511	1,212
Asset retirement obligations related to support equipment and facilities	75	41
(Decrease) increase in liabilities for oil and natural gas properties capital expenditures	(3,476)	(9,909)
(Decrease) increase in liabilities for support equipment and facilities	(11,565)	3,859
Increase in liabilities for accrued cost to issue equity	62	0
Stock-based compensation expense recognized as liability	88	583
Transfer of inventory from oil and natural gas properties	$ 474	$ 456