Oil and Gas Producing Activities - Schedule of Information Regarding Costs Incurred for Oil and Gas Property Acquisition, Development and Exploration Activities (Parenthetical) (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items] | |||
| Development costs | $ 146,237 | $ 382,995 | $ 287,898 |
| Non-cash Asset Retirement Obligations [Member] | |||
| Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items] | |||
| Development costs | $ 151,000 | $ 898,000 | $ 584,000 |