Supplemental Oil and Gas Disclosures - Cost Incurred in Oil and Gas Property Acquisition Exploration and Development Activities (Parenthetical) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Capitalized Costs Oil And Gas Producing Activities Net [Abstract] | |||
| Additions (reductions) of asset retirement obligations | $ 10.8 | $ (0.4) | $ 88.0 |
| Seismic costs | 0.2 | 3.2 | 9.0 |
| Geological and geophysical costs | $ 4.1 | $ 5.7 | $ 7.3 |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Asset retirement obligation period increase decrease due to acquisitions, incurred and revisions of estimates. No definition available.
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| X | ||||||||||
- Definition Geological and Geophysical costs incurred related to development and exploration of oil and gas properties. These costs are included in operating expenses, and therefore are an adjustment to derive costs related to the acquisition of oil and gas properties. No definition available.
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| X | ||||||||||
- Definition Seismic costs incurred for the development and exploration of oil and gas properties. These costs are included in operating expenses, and therefore are an adjustment to derive costs related to the acquisition of oil and gas properties. No definition available.
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