ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2018 |
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| Site Contingency [Line Items] | ||
| Accrual for Environmental Loss Contingencies | $ 2.9 | $ 2.5 |
| Environmental Loss Contingency And Mine Reclamation And Closing Liability Current And Noncurrent | 171.3 | $ 174.9 |
| Accrual for Environmental Loss Contingencies, Period Increase (Decrease) | $ (26.2) |
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- Definition Environmental Loss Contingency And Mine Reclamation And Closing Liability Current And Noncurrent No definition available.
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| X | ||||||||||
- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Increase (decrease) in the accrual for environmental loss contingencies during the reporting period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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