Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS (Derivative Instruments in Financial Position) (Details)

v3.20.1
DERIVATIVE INSTRUMENTS (Derivative Instruments in Financial Position) (Details) - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Derivatives, Fair Value [Line Items]    
Total short-term derivative instruments - asset $ 171,755 $ 126,201
Total long-term derivative instruments - asset 0 563
Total short-term derivative instruments - liability 67 303
Total long-term derivative instruments - liability 70,829 53,135
Total net asset derivative position 100,859 73,326
Commodity derivative instruments    
Derivatives, Fair Value [Line Items]    
Total short-term derivative instruments - asset 171,755 125,383
Contingent consideration arrangement    
Derivatives, Fair Value [Line Items]    
Total short-term derivative instruments - asset   818
Total long-term derivative instruments - asset $ 0 $ 563