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Fair Value Measurements (Fair Value of Liabilities Measured on Recurring Basis) (Details) (USD $)
In Thousands, unless otherwise specified |
9 Months Ended | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Sep. 30, 2012
|
Dec. 31, 2011
|
Sep. 30, 2012
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2011
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2012
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2011
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2012
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2011
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2012
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 2011
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Sep. 30, 2012
Fair Value on a nonrecurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2011
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2011
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2011
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 2011
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Sep. 30, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2011
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2011
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2011
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 2011
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Sep. 30, 2012
Current liabilities - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2012
Current liabilities - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2012
Current liabilities - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2012
Current liabilities - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Sep. 30, 2012
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2012
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2012
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2012
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
|
| Derivative Assets | |||||||||||||||||||||||||||||||||||
| Derivative Assets, Current | $ 2,013 | $ 2,499 | $ 0 | $ 2,013 | $ 2,499 | $ 0 | $ 2,013 | $ 2,499 | |||||||||||||||||||||||||||
| Derivative Assets, Noncurrent | 0 | 969 | 0 | 969 | |||||||||||||||||||||||||||||||
| Derivative Liabilities | |||||||||||||||||||||||||||||||||||
| Derivative Liabilities, Current | 224 | 0 | 0 | 224 | 0 | 224 | |||||||||||||||||||||||||||||
| Derivative Liabilities, Noncurrent | 0 | 312 | 0 | 312 | |||||||||||||||||||||||||||||||
| Derivative Assets (Liabilities), at Fair Value, Net | 0 | 2,446 | 2,499 | 0 | 2,446 | 2,499 | |||||||||||||||||||||||||||||
| Asset Retirement Obligation, Fair Value Disclosure | $ 0 | ||||||||||||||||||||||||||||||||||