Derivative Financial Instruments (Derivatives And Hedging-Overall-Subsequent Measurement) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2020 |
Sep. 30, 2019 |
Sep. 30, 2020 |
Sep. 30, 2019 |
|
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | $ (9,074) | $ 8,135 | $ 84,097 | $ (59,829) |
| Commodity Contract [Member] | Sales [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | (7,734) | 17,626 | 89,280 | (41,504) |
| Commodity Contract [Member] | Cost of Sales [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | 1,815 | (5,581) | (2,529) | (9,456) |
| Energy Related Derivative [Member] | Other Operating Income (Expense) [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | $ (3,155) | $ (3,910) | $ (2,654) | $ (8,869) |