Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments - Fair value (Details)

v3.10.0.1
Derivative Instruments - Fair value (Details)
$ in Thousands
Jun. 30, 2018
USD ($)
item
Dec. 31, 2017
USD ($)
item
Fair value of derivative instruments    
Current portion of fair value of derivative assets $ 420,842 $ 460,685
Noncurrent portion of fair value of derivative assets 763,592 841,257
Current portion of fair value of derivative liabilities 30,661 28,476
Noncurrent portion of fair value of derivative liabilities   207
Commodity derivative    
Fair value of derivative instruments    
Total asset derivatives 1,184,434 1,301,942
Total liability derivatives 9,233 7,289
Marketing derivative    
Fair value of derivative instruments    
Total liability derivatives 21,428 21,394
Derivatives not designated as hedges for accounting purposes    
Fair value of derivative instruments    
Total asset derivatives 1,184,434 1,301,942
Total liability derivatives 30,661 28,683
Net derivatives 1,153,773 1,273,259
Derivatives not designated as hedges for accounting purposes | Commodity derivative    
Fair value of derivative instruments    
Current portion of fair value of derivative assets 420,842 460,685
Noncurrent portion of fair value of derivative assets 763,592 841,257
Current portion of fair value of derivative liabilities 9,233 7,082
Noncurrent portion of fair value of derivative liabilities   207
Derivatives not designated as hedges for accounting purposes | Marketing derivative    
Fair value of derivative instruments    
Current portion of fair value of derivative liabilities $ 21,428 $ 21,394
Derivatives designated as hedges for accounting purposes    
Fair value of derivative instruments    
Number of derivative instruments held designated as hedges | item 0 0