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Location and Amounts of Derivative Gains and Losses in Condensed Consolidated Statements of Income (Detail) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | 9 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
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Sep. 30, 2013
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Sep. 30, 2012
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Sep. 30, 2013
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Sep. 30, 2012
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Derivatives in Cash Flow Hedging Relationships | Interest rate contracts
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| Derivative Instruments, Gain (Loss) [Line Items] | ||||||||
| Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion) | $ 0 | [1] | $ 60 | [1] | ||||
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Derivatives Not Designated as Hedging Instruments | Commodity contracts | Net realized and unrealized gains (losses) on fuel price derivatives
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| Derivative Instruments, Gain (Loss) [Line Items] | ||||||||
| Amount of Gain or (Loss) Recognized in Income on Derivative | (3,640) | (14,026) | (2,781) | (12,046) | ||||
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Financing interest expense | Derivatives in Cash Flow Hedging Relationships
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| Derivative Instruments, Gain (Loss) [Line Items] | ||||||||
| Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) | 0 | (109) | ||||||
| Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) | $ 0 | $ 0 | ||||||
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