cm:Concept: us-gaap:OperatingLeasesIncomeStatementCarryingAmountAtLeaseInceptionExceedsFairValue
| Operating Leases, Income Statement, Carrying Amount at Lease Inception Exceeds Fair Value |
| us-gaap:OperatingLeasesIncomeStatementCarryingAmountAtLeaseInceptionExceedsFairValue |
| This element represents the loss resulting from the amount by which the cost or carrying amount, if different, of an asset subject to an agreement classified as an operating lease, at the inception of a lease involving real estate, exceeds the fair value of the leased property. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:OperatingLeasesIncomeStatementCarryingAmountAtLeaseInceptionExceedsFairValue |