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Asset Retirement Obligations - Schedule of Change in Asset Retirement Obligations (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Asset Retirement Obligation [Abstract]    
Asset retirement obligations at beginning of period $ 2,683 $ 7,488
Wells drilled during the year 220 154
Wells acquired during the year 2,797 28
Wells sold during the year   (4,780)
Accretion of discount 139 180
Revisions of previous estimates (190) (205)
Wells plugged and abandoned during the year   (182)
Asset retirement obligations at end of period $ 5,649 $ 2,683