Supplemental Disclosures (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Increase in liabilities for oil and natural gas properties capital expenditures	$ 5,863	$ 2,820
Increase (decrease) in liabilities for midstream properties capital expenditures	8,090	(6,329)
Stock-based compensation expense recognized as liability	(102)	(152)
Decrease in liabilities for accrued cost to issue equity	0	(294)
Transfer of inventory (to) from oil and natural gas properties	(176)	31
Transfer of inventory to other property and equipment	(820)	0
Mineral Properties
Condensed Cash Flow Statements, Captions [Line Items]
Increase (decrease) in asset retirement obligations	337	1,434
Midstream Properties
Condensed Cash Flow Statements, Captions [Line Items]
Increase (decrease) in asset retirement obligations	$ 0	$ (194)