|
Derivative Instruments and Hedging Activities (Derivatives Fair Value By Balance Sheet Location) (Details) (USD $)
In Thousands, unless otherwise specified
|
Jun. 30, 2012
|
Dec. 31, 2011
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Net |
$ 6,627
|
$ 2,499
|
| Derivative Liability, Fair Value, Net |
(350)
|
0
|
| Derivative, Fair Value, Net |
6,277
|
2,499
|
|
Designated as Hedging Instrument [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Net |
2,702
|
2,499
|
| Derivative Liability, Fair Value, Net |
0
|
0
|
| Derivative, Fair Value, Net |
2,702
|
2,499
|
|
Not Designated as Hedging Instrument [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Net |
3,925
|
0
|
| Derivative Liability, Fair Value, Net |
(350)
|
0
|
| Derivative, Fair Value, Net |
3,575
|
0
|
|
Current assets - Fair market value of derivatives [Member] | Designated as Hedging Instrument [Member] | Natural gas [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Asset |
0
|
0
|
| Derivative Liability, Fair Value, Gross Asset |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Asset Net |
0
|
0
|
|
Current assets - Fair market value of derivatives [Member] | Not Designated as Hedging Instrument [Member] | Natural gas [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Asset |
19
|
0
|
| Derivative Liability, Fair Value, Gross Asset |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Asset Net |
19
|
0
|
|
Non-current assets - Other long-term assets [Member] | Designated as Hedging Instrument [Member] | Natural gas [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Asset |
0
|
0
|
| Derivative Liability, Fair Value, Gross Asset |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Asset Net |
0
|
0
|
|
Non-current assets - Other long-term assets [Member] | Not Designated as Hedging Instrument [Member] | Crude oil [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Asset |
1,982
|
0
|
| Derivative Liability, Fair Value, Gross Asset |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Asset Net |
1,982
|
0
|
|
Current liabilities - Fair market value of derivatives [Member] | Designated as Hedging Instrument [Member] | Crude oil [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Liability |
2,702
|
2,499
|
| Derivative Liability, Fair Value, Gross Liability |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Liability Net |
2,702
|
2,499
|
|
Current liabilities - Fair market value of derivatives [Member] | Not Designated as Hedging Instrument [Member] | Crude oil [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Liability |
1,924
|
0
|
| Derivative Liability, Fair Value, Gross Liability |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Liability Net |
1,924
|
0
|
|
Non-current liabilities - Other long-term liabilities [Member] | Designated as Hedging Instrument [Member] | Crude oil [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Liability |
0
|
0
|
| Derivative Liability, Fair Value, Gross Liability |
0
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Liability Net |
0
|
0
|
|
Non-current liabilities - Other long-term liabilities [Member] | Not Designated as Hedging Instrument [Member] | Natural gas [Member]
|
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset, Fair Value, Gross Liability |
0
|
0
|
| Derivative Liability, Fair Value, Gross Liability |
(350)
|
0
|
| Derivative Assets (Liability), Fair Value, Gross Liability Net |
$ (350)
|
$ 0
|