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, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | $ 8,135 | $ (12,689) | $ (59,829) | $ (54,082) |
| Commodity Contract [Member] | Sales [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | 17,626 | (24,354) | (41,504) | (70,140) |
| Commodity Contract [Member] | Cost of Sales [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | (5,581) | 11,665 | (9,456) | 16,058 |
| Energy Related Derivative [Member] | Other Operating Income (Expense) [Member] | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Derivative, Gain (Loss) on Derivative, Net | $ (3,910) | $ 0 | $ (8,869) | $ 0 |