|
Summary of Significant Accounting Policies Asset Retirement Obligations (Details) (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
|
| Asset Retirement Obligation Disclosure [Abstract] | |||
| Asset Retirement Obligation | $ 43,538 | $ 49,879 | $ 102,465 |
| Asset Retirement Obligation, Liabilities Incurred | 8,718 | 18,292 | |
| Asset Retirement Obligation, Revision of Estimate | (2,096) | (75,900) | |
| Asset Retirement Obligation, Accretion Expense | 6,531 | 17,171 | |
| Asset Retirement Obligation, Liabilities Settled | (9,844) | 323 | |
| Asset Retirement Obligation, Foreign Currency Translation | $ (9,650) | $ (12,472) | |