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Acquisitions and Divestitures - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Dec. 20, 2017
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Business Acquisition [Line Items]          
Proceeds from sales of oil and gas properties       $ 210 $ 2,416
Bold Transaction          
Business Acquisition [Line Items]          
Revenues     $ 24,300 51,600  
Direct operating expenses   $ 12,300   $ 22,600  
Williston Basin          
Business Acquisition [Line Items]          
Proceeds from sales of oil and gas properties $ 27,300        
Purchase price adjustment $ 300