Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS AND PRICE RISK MANAGEMENT - Reconciliation between the gross assets and liabilities and the amounts reflected on the balance sheet (Details)

v3.19.1
DERIVATIVE INSTRUMENTS AND PRICE RISK MANAGEMENT - Reconciliation between the gross assets and liabilities and the amounts reflected on the balance sheet (Details) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Offsetting Assets [Line Items]    
Current Derivative Assets $ 18,578 $ 115,870
Noncurrent Derivative Assets 17,839 61,843
Total derivative assets 36,417 177,713
Current liabilities (5,882) 0
Noncurrent liabilities (4,991) 0
Total derivative liabilities (10,873) 0
Gross Amounts of Recognized Assets, Offsetting of Derivative Assets 57,508 178,477
Gross Amounts Offset in the Balance Sheet, Offsetting of Derivative Assets (21,091) (764)
Net Amounts of Assets Presented in the Balance Sheet, Offsetting of Derivative Assets 36,417 177,713
Gross Amounts of Recognized Assets, Offsetting of Derivative Liabilities (31,964) (764)
Gross Amounts Offset in the Balance Sheet, Offsetting of Derivative Liabilities 21,091 764
Net Amounts of Assets Presented in the Balance Sheet, Offsetting of Derivative Liabilities (10,873) 0
Current Assets    
Offsetting Assets [Line Items]    
Gross Amounts of Recognized Assets, Offsetting of Derivative Assets 31,558 116,620
Gross Amounts Offset in the Balance Sheet, Offsetting of Derivative Assets (12,980) (750)
Net Amounts of Assets Presented in the Balance Sheet, Offsetting of Derivative Assets 18,578 115,870
Noncurrent Assets    
Offsetting Assets [Line Items]    
Gross Amounts of Recognized Assets, Offsetting of Derivative Assets 25,950 61,857
Gross Amounts Offset in the Balance Sheet, Offsetting of Derivative Assets (8,111) (14)
Net Amounts of Assets Presented in the Balance Sheet, Offsetting of Derivative Assets 17,839 61,843
Current Liabilities    
Offsetting Assets [Line Items]    
Gross Amounts of Recognized Assets, Offsetting of Derivative Liabilities (18,862) (750)
Gross Amounts Offset in the Balance Sheet, Offsetting of Derivative Liabilities 12,980 750
Net Amounts of Assets Presented in the Balance Sheet, Offsetting of Derivative Liabilities (5,882) 0
Noncurrent Liabilities    
Offsetting Assets [Line Items]    
Gross Amounts of Recognized Assets, Offsetting of Derivative Liabilities (13,102) (14)
Gross Amounts Offset in the Balance Sheet, Offsetting of Derivative Liabilities 8,111 14
Net Amounts of Assets Presented in the Balance Sheet, Offsetting of Derivative Liabilities (4,991) 0
Swap Price Contracts | Current Assets    
Offsetting Assets [Line Items]    
Current Derivative Assets 17,973 108,514
Swap Price Contracts | Noncurrent Assets    
Offsetting Assets [Line Items]    
Noncurrent Derivative Assets 17,839 61,843
Swap Price Contracts | Current Liabilities    
Offsetting Assets [Line Items]    
Current liabilities (5,882) 0
Swap Price Contracts | Noncurrent Liabilities    
Offsetting Assets [Line Items]    
Noncurrent liabilities (4,991) 0
Basis Swap Contracts | Current Assets    
Offsetting Assets [Line Items]    
Current Derivative Assets $ 606 $ 7,356