|
Amount of Commodity Derivative Instrument Gains Losses (Detail) (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2013
|
Dec. 31, 2012
|
Dec. 31, 2011
|
|
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Commodity derivative settlements | $ 35,812 | $ 22,920 | $ 20,799 |
| Commodity derivative instruments gain (loss) | (15,336) | 5,176 | (5,321) |
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Commodity Derivative Instrument Gains
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| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Commodity derivative settlements | (35,812) | (22,920) | (20,799) |
| Mark-to-market gain | 20,476 | 28,096 | 15,478 |
| Commodity derivative instruments gain (loss) | $ (15,336) | $ 5,176 | $ (5,321) |