Derivative Financial Instruments - Changes in Fair Value and Settlements of Commodity Derivative Contracts (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
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| Gain Loss On Derivative Instruments Net Pretax [Abstract] | ||||
| Derivative (gain) loss | $ 6,219 | $ (3,689) | $ 6,219 | $ (7,644) |
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- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- References No definition available.
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