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Asset Retirement Obligations (ARO) (Tables) | 12 Months Ended
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Dec. 31, 2011
Asset Retirement Obligations (ARO) [Abstract] |
Schedule of Change in Asset Retirement Obligations | The reconciliation of the changes in the asset retirement obligations is presented below:
|  | Year ended December 31, |
|  | 2011 |  |  | 2010 |
Beginning balance, ARO liability |  | $ | 14,274 |  |  | $ | 15,233 |
Additional ARO liability incurred |  |  | 1,110 |  |  |  | 1,057 |
ARO liabilities settled |  |  | (1,315 | ) |  |  | (1,162 | )
Accretion expense |  |  | 1,102 |  |  |  | 1,040 |
Adjustments (1) |  |  | - |  |  |  | (1,894 | )
Ending balance, ARO liability |  | $ | 15,171 |  |  | $ | 14,274 |
(1) | We adjusted our ARO liability in 2010 for changes in the estimated amounts and timing of costs associated with the disposal of spent pot liner.

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- Definition Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Topic 410 -SubTopic 30 -Publisher FASB -Number -Article -Subparagraph -Name Accounting Standards Codification -Paragraph 5 -Section 50 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859 + Details
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