cm:Level3TextBlock: us-gaap:SummaryOfTaxCreditCarryforwardsTextBlock
| Summary of Tax Credit Carryforwards [Table Text Block] |
| us-gaap:SummaryOfTaxCreditCarryforwardsTextBlock |
| Tabular disclosure of tax credit carryforwards available to reduce future taxable income, including amounts, expiration dates, limitations on use and the related deferred tax assets and valuation allowances. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
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| us-gaap:SummaryOfTaxCreditCarryforwardsTextBlock |
| TaxCreditCarryforward |