Disclosures About Oil and Gas Producing Activities - Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Natural Gas Reserves (Detail) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|---|
| Extractive Industries [Abstract] | ||||
| Future cash flows | $ 4,451,665 | $ 3,319,551 | $ 4,097,568 | |
| Future production costs | (1,279,777) | (1,054,211) | (1,237,888) | |
| Future development costs | (982,284) | (829,926) | (934,814) | |
| Future income tax expense | (323,308) | (132,834) | (307,374) | |
| Future net cash flows | 1,866,296 | 1,302,580 | 1,617,492 | |
| 10% annual discount for estimated timing of cash flows | (1,405,265) | (1,004,825) | (1,157,097) | |
| Standardized measure of discounted future net cash flows | $ 461,031 | $ 297,755 | $ 460,395 | $ 1,055,815 |
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- References No definition available.
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- Definition Amount of estimated future accumulated cash inflow from the sale of proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of estimated future accumulated cash outflow for costs to be incurred in developing proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of estimated future accumulated cash outflow for income tax, based on the future income less future expense derived from production and sale of proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount, after future accumulated cash outflow for development and production costs and future income tax, of estimated future accumulated cash inflow from the sale of proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of estimated future accumulated cash outflow for costs to be incurred in producing proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of discount on future accumulated cash inflow, after deducting future accumulated cash outflow for development and production costs and future income tax, from sale of proved oil and gas reserves, using a discount rate of ten percent a year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of discounted future accumulated cash inflow relating to proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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