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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, 2013
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Dec. 31, 2012
|
Sep. 30, 2013
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2012
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2013
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2012
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2013
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2012
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2013
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 2012
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Sep. 30, 2013
Fair Value on a nonrecurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2013
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2013
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2013
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2012
Current assets - Fair market value of derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2013
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, 2012
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, 2013
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2013
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2013
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2013
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 2012
Other long-term assets [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Sep. 30, 2013
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Dec. 31, 2012
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2013
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2012
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2013
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Dec. 31, 2012
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2013
Current Liabilities - Fair Market Value of Derivatives [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 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, 2013
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 1 [Member]
|
Sep. 30, 2013
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Dec. 31, 2012
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 2 [Member]
|
Sep. 30, 2013
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Level 3 [Member]
|
Sep. 30, 2013
Other long-term liabilities [Member]
Fair Value on a recurring basis [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
|
Dec. 31, 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 | $ 0 | $ 1,674 | $ 0 | $ 0 | $ 0 | $ 1,674 | $ 0 | $ 0 | $ 0 | $ 1,674 | |||||||||||||||||||||||||||||||
| Derivative Assets, Noncurrent | 0 | 0 | 36 | 250 | 0 | 0 | 36 | 250 | |||||||||||||||||||||||||||||||||
| Derivative Assets | 0 | 0 | 36 | 1,924 | 0 | 0 | 36 | 1,924 | |||||||||||||||||||||||||||||||||
| Derivative Liabilities | |||||||||||||||||||||||||||||||||||||||||
| Derivative Liabilities, Current | 1,139 | 125 | 0 | 0 | 1,139 | 125 | 0 | 0 | 1,139 | 125 | |||||||||||||||||||||||||||||||
| Derivative Liabilities, Noncurrent | 0 | 18 | 116 | 0 | 18 | 116 | |||||||||||||||||||||||||||||||||||
| Derivative Liabilities | 0 | 0 | 1,157 | 241 | 0 | 0 | 1,157 | 241 | |||||||||||||||||||||||||||||||||
| Derivative Assets (Liabilities), at Fair Value, Net | 0 | 0 | (1,121) | 1,683 | 0 | 0 | (1,121) | 1,683 | |||||||||||||||||||||||||||||||||
| Asset Retirement Obligation, Fair Value Disclosure | $ 0 | ||||||||||||||||||||||||||||||||||||||||