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Unaudited Supplemental Oil and Gas Information - Schedule of Standardized Measure of Discounted Future Net Cash Flows (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Oil and Gas Exploration and Production Industries Disclosures [Abstract]        
Future cash inflows $ 34,424 $ 27,769 $ 78,646  
Production costs (18,518) (18,814) (44,685)  
Development costs (8,050)  
Income taxes  
Future net cash flows 15,906 8,955 25,911  
10% annual discount factor (6,653) (2,208) (8,143)  
Standardized measure of discounted future net cash flows $ 9,253 $ 6,747 $ 17,768 $ 81,889