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Derivative Instruments and Hedging Activities (Derivatives Designated as Hedging Instruments/ Derivatives Not Designated as Hedging Instruments) (Details) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | |
|---|---|---|
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Mar. 31, 2013
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Mar. 31, 2012
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| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Unrealized gain (loss), net | $ (1,039) | $ 299 |
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Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member]
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| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of gain (loss) reclassified from OCI into income (effective portion) | 0 | 0 |
| Amount of gain (loss) recognized in income (ineffective portion and amount excluded from effectiveness testing) | 0 | 230 |
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Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
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| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Unrealized gain (loss), net | (418) | 70 |
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Commodity Contract [Member] | Natural gas [Member] | Not Designated as Hedging Instrument [Member]
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| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Realized gain (loss), net | 49 | 0 |
| Total gain (loss), net | (339) | 0 |
| Unrealized gain (loss), net | (388) | 0 |
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Commodity Contract [Member] | Crude Oil [Member] | Not Designated as Hedging Instrument [Member]
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| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Realized gain (loss), net | 573 | 0 |
| Total gain (loss), net | (79) | 70 |
| Unrealized gain (loss), net | $ (652) | $ 70 |