cm:Concept: us-gaap:FairValueOptionRelationToMeasurementInputs
| Fair Value, Option, Relation to Measurement Inputs |
| us-gaap:FairValueOptionRelationToMeasurementInputs |
| For each line item in the statement of financial position that includes an item or items for which the fair value option has been elected, this element represents information to enable users of the financial statements to understand how each line item in the statement of financial position relates to major categories of assets and liabilities in terms of the fair value measurement hierarchy. The fair value measurement hierarchy consists of three levels including: using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:FairValueOptionRelationToMeasurementInputs |