| Standard label: | Accrued Reclamation Costs, Current |
| Name: | us-gaap:AccruedReclamationCostsCurrent |
| Documentation: | Current portion of reclamation reserve to restore a mining or drilling site to the condition agreed upon within the mining or drilling contract. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AccruedReclamationCostsCurrent |
| Label | Role | Language |
| Accrued Reclamation Costs, Current | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 210 10 S99 1 (SX 210.5-02.20) | http://fasb.org/us-gaap/role/ref/legacyRef | 210 |
| FASB Accounting Standards Codification 210 10 45 6 | http://fasb.org/us-gaap/role/ref/legacyRef | 210 |
| Part Of Roll Up: |
| us-gaap:LiabilitiesCurrent |