Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments - Fair value (Details)

v3.19.1
Derivative Instruments - Fair value (Details)
$ in Thousands
Mar. 31, 2019
USD ($)
item
Dec. 31, 2018
USD ($)
item
Fair value of derivative instruments    
Current portion of fair value of derivative assets $ 122,425 $ 245,263
Noncurrent portion of fair value of derivative assets 313,909 362,169
Current portion of fair value of derivative liabilities 3,894 532
Commodity derivative    
Fair value of derivative instruments    
Total asset derivatives 436,334 607,432
Total liability derivatives 3,894 532
Derivatives not designated as hedges for accounting purposes    
Fair value of derivative instruments    
Total asset derivatives 436,334 607,432
Total liability derivatives 3,894 532
Net derivatives 432,440 606,900
Derivatives not designated as hedges for accounting purposes | Commodity derivative    
Fair value of derivative instruments    
Current portion of fair value of derivative assets 122,425 245,263
Noncurrent portion of fair value of derivative assets 313,909 362,169
Current portion of fair value of derivative liabilities $ 3,894 $ 532
Derivatives designated as hedges for accounting purposes    
Fair value of derivative instruments    
Number of derivative instruments held designated as hedges | item 0 0