Supplemental Disclosures (Details 1) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Cash paid for interest expense, net of amounts capitalized	$ 29,773	$ 14,542
Increase in liabilities for oil and natural gas properties capital expenditures	5,157	35,940
Increase (decrease) in liabilities for midstream properties capital expenditures	1,864	(247)
Stock-based compensation expense recognized as liability	(107)	150
Decrease in liabilities for accrued cost to issue equity	0	(343)
Increase in liabilities for accrued cost to issue senior notes	510	0
Transfer of inventory from oil and natural gas properties	305	74
Transfer of inventory to midstream and other property and equipment	(2,691)	0
Mineral Properties
Condensed Cash Flow Statements, Captions [Line Items]
Increase (decrease) in asset retirement obligations	1,705	2,484
Midstream Properties
Condensed Cash Flow Statements, Captions [Line Items]
Increase (decrease) in asset retirement obligations	$ 547	$ (138)