Asset Retirement Obligations (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2018 |
Mar. 31, 2019 |
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| Asset Retirement and Reclamation Obligations | ||
| Estimated Future Cash Undiscounted Amount | $ 29,900 | |
| Change in estimated liability | $ 2,840 |
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- Definition Amount of estimated future cash undiscounted amount. No definition available.
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- References No definition available.
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- Definition Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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