cm:Level2TextBlock: us-gaap:IncomeTaxUncertaintiesPolicy
| Income Tax Uncertainties, Policy [Policy Text Block] |
| us-gaap:IncomeTaxUncertaintiesPolicy |
| Disclosure of accounting policy for tax positions taken in the tax return filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities and other types of contingencies related to income taxes. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:IncomeTaxUncertaintiesPolicy |