| Standard label: | Carrying Costs, Property and Exploration Rights |
| Name: | us-gaap:CarryingCostsPropertyAndExplorationRights |
| Documentation: | The costs incurred to retain exploration and property rights after acquisition but before production has occurred. Costs include legal costs for title defense, ad valorem taxes on nonproducing mineral properties, shut-in royalties, and delay rentals. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:CarryingCostsPropertyAndExplorationRights |
| Label | Role | Language |
| Carrying Costs, Property and Exploration Rights | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03.3) | http://fasb.org/us-gaap/role/ref/legacyRef | 220 |
| FASB Accounting Standards Codification 230 10 45 28 (b) | http://fasb.org/us-gaap/role/ref/legacyRef | 230 |
| Part Of Roll Up: |
| us-gaap:OperatingCostsAndExpenses |
| us-gaap:AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities |