cm:Level2TextBlock: us-gaap:FairValueMeasurementPolicyPolicyTextBlock
| Fair Value Measurement, Policy [Policy Text Block] |
| us-gaap:FairValueMeasurementPolicyPolicyTextBlock |
| Disclosure of accounting policy for fair value measurements of financial and non-financial assets, liabilities and instruments classified in shareholders' equity. Disclosures include, but are not limited to, how an entity that manages a group of financial assets and liabilities on the basis of its net exposure measures the fair value of those assets and liabilities. |
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| us-gaap:FairValueMeasurementPolicyPolicyTextBlock |