cm:Level3TextBlock: us-gaap:CapitalizedCostsRelatingToOilAndGasProducingActivitiesDisclosureTextBlock
| Capitalized Costs Relating to Oil and Gas Producing Activities Disclosure [Table Text Block] |
| us-gaap:CapitalizedCostsRelatingToOilAndGasProducingActivitiesDisclosureTextBlock |
| Tabular disclosure of aggregate capitalized costs relating to an enterprise's oil and gas producing activities and the aggregate related accumulated depreciation, depletion, amortization, and valuation allowances. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
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| us-gaap:CapitalizedCostsRelatingToOilAndGasProducingActivitiesDisclosureTextBlock |