Supplemental Disclosures (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Supplemental disclosures of cash flow information
Asset retirement obligations related to mineral properties	$ 1,434	$ 1,606
Asset retirement obligations related to support equipment and facilities	(194)	(65)
(Decrease) increase in liabilities for oil and natural gas properties capital expenditures	2,820	(11,622)
(Decrease) increase in liabilities for support equipment and facilities	(6,329)	(5,000)
Issuance Of Restricted Stock Units For Board And Advisor Services	0	138
Stock-based compensation expense recognized as liability	(152)	(98)
Increase (Decrease) in Liabilities for Accrued Cost to Issue Equity	(294)	216
Transfer of inventory from oil and natural gas properties	$ 31	$ 64