cm:Level2TextBlock: us-gaap:FinanceLoanAndLeaseReceivablesHeldForInvestmentAllowanceAndNonperformingLoansNonperformingLoansPolicy
| Finance, Loan and Lease Receivables, Held-for-investment, Allowance and Nonperforming Loans, Nonperforming Loans Policy [Policy Text Block] |
| us-gaap:FinanceLoanAndLeaseReceivablesHeldForInvestmentAllowanceAndNonperformingLoansNonperformingLoansPolicy |
| Disclosure of accounting policy for (1) placing loans on nonaccrual status (or discontinuing accrual of interest) and recording payments received on nonaccrual loans, and the policy for resuming accrual of interest, (2) charging-off uncollectible loans, and (3) determining past due or delinquency status (that is, whether past due status is based on how recently payments have been received or contractual terms). |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:FinanceLoanAndLeaseReceivablesHeldForInvestmentAllowanceAndNonperformingLoansNonperformingLoansPolicy |