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Significant Customers (Details) - Customer Concentration Risk - Sales Revenue, Net
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Shell Trading (US) Company    
Concentration Risk [Line Items]    
Revenue percentage accounted by purchasers 40.00% 54.00%
Lion Oil, Inc.    
Concentration Risk [Line Items]    
Revenue percentage accounted by purchasers 31.00% 28.00%
Targa Pipeline Mid-Continent, LLC    
Concentration Risk [Line Items]    
Revenue percentage accounted by purchasers 5.00% 11.00%
Trafigura Trading LLC    
Concentration Risk [Line Items]    
Revenue percentage accounted by purchasers 17.00% 1.00%