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Location and Amounts of Derivative Fair Values in Condensed Consolidated Balance Sheets (Detail) (Derivatives Not Designated as Hedging Instruments, Commodity contracts, Fuel price derivatives, at fair value, USD $)
In Thousands, unless otherwise specified |
Sep. 30, 2013
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Dec. 31, 2012
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Derivatives Not Designated as Hedging Instruments | Commodity contracts | Fuel price derivatives, at fair value
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| Derivatives, Fair Value [Line Items] | ||
| Derivatives Classified as Assets | $ 488 | $ 0 |
| Derivatives Classified as Liabilities | $ 983 | $ 1,729 |