cm:Concept: us-gaap:AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock
| Adjustments to Additional Paid in Capital, Increase in Carrying Amount of Redeemable Preferred Stock |
| us-gaap:AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock |
| Amount of decrease (increase) in additional paid in capital (APIC) for the increase in carrying amount of redeemable preferred stock. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock |