Fair Value Measurements (Schedule of Derivative Instruments) (Details) - USD ($) $ in Thousands |
6 Months Ended | ||
|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Dec. 31, 2017 |
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| Liabilities | |||
| Asset retirement obligation capitalized | $ 909 | $ 9,505 | |
| Level 1 | |||
| Assets | |||
| Derivative Instruments | 0 | $ 0 | |
| Liabilities | |||
| Derivative Instruments | 0 | 0 | |
| Level 2 | |||
| Assets | |||
| Derivative Instruments | 28,402 | 87,532 | |
| Liabilities | |||
| Derivative Instruments | 78,640 | 35,523 | |
| Level 3 | |||
| Assets | |||
| Derivative Instruments | 0 | 0 | |
| Liabilities | |||
| Derivative Instruments | $ 0 | $ 0 | |
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- Definition Amount of asset retirement obligations incurred during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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