cm:Concept: us-gaap:TemporaryEquityIssuePeriodIncreaseOrDecrease
| Temporary Equity, Carrying Amount, Period Increase (Decrease) |
| us-gaap:TemporaryEquityIssuePeriodIncreaseOrDecrease |
| Change in the value of each type or class of stock classified as temporary equity during the period. The redemption requirement does not constitute an unconditional obligation that will be settled in a variable number of shares constituting a monetary value predominantly indexed to (a) a fixed monetary amount known at inception, (b) an amount inversely correlated with the residual value of the entity, or (c) an amount determined by reference to something other than the fair value of issuer's stock. Does not include mandatorily redeemable stock. The exception is if redemption is required upon liquidation or termination of the reporting entity. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:TemporaryEquityIssuePeriodIncreaseOrDecrease |