|
Costs Related to Purchase Obligations (Details) (USD $)
In Thousands, unless otherwise specified |
6 Months Ended | |
|---|---|---|
|
Jun. 30, 2013
|
Jun. 30, 2012
|
|
| Schedule of Costs Related to Purchase Obligations [Line Items] | ||
| Total costs related to purchase obligations | $ 72,037 | $ 76,457 |
|
Major equipment purchases
|
||
| Schedule of Costs Related to Purchase Obligations [Line Items] | ||
| Total costs related to purchase obligations | 15,116 | 31,989 |
|
Firm transportation expense
|
||
| Schedule of Costs Related to Purchase Obligations [Line Items] | ||
| Total costs related to purchase obligations | 31,017 | 15,822 |
|
Gas drilling obligations
|
||
| Schedule of Costs Related to Purchase Obligations [Line Items] | ||
| Total costs related to purchase obligations | 25,904 | 28,517 |
|
Other Obligations
|
||
| Schedule of Costs Related to Purchase Obligations [Line Items] | ||
| Total costs related to purchase obligations | $ 0 | $ 129 |