Quarterly report pursuant to Section 13 or 15(d)

Derivatives. (Details) - Schedule of derivatives not designated as hedging instruments

v3.21.1
Derivatives. (Details) - Schedule of derivatives not designated as hedging instruments - Not Designated as Hedging Instrument [Member] - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Commodity contracts [Member]    
Derivatives. (Details) - Schedule of derivatives not designated as hedging instruments [Line Items]    
Assets, fair value $ 22,355 $ 17,149
Liabilities, fair value $ 4,741
Cash collateral balance [Member]    
Derivatives. (Details) - Schedule of derivatives not designated as hedging instruments [Line Items]    
Assets, fair value   $ 520