|
Derivative Financial Instruments Schedule of Derivative Offset Amounts (Details) (Exchange Traded [Member], USD $)
In Thousands, unless otherwise specified |
Jun. 30, 2014
|
Dec. 31, 2013
|
|---|---|---|
| Derivative [Line Items] | ||
| Derivative Liability, Fair Value, Gross Liability | $ (16,577) | $ (7,167) |
| Derivative Asset, Fair Value, Gross Asset | 1,920 | 2,665 |
| Derivative Liability Amount Not Offset | (14,657) | (4,502) |
| Derivative Liability, Fair Value of Collateral | 29,070 | 14,782 |
| Margin Deposit Net of Commodity Contract | 14,413 | 10,280 |
|
Other Current Liabilities [Member]
|
||
| Derivative [Line Items] | ||
| Derivative Liability Amount Not Offset | (11,140) | (6,737) |
|
Other Noncurrent Liabilities [Member]
|
||
| Derivative [Line Items] | ||
| Derivative Liability Amount Not Offset | (3,517) | |
|
Other Noncurrent Assets [Member]
|
||
| Derivative [Line Items] | ||
| Derivative Liability Amount Not Offset | $ 2,235 |