cm:Concept: us-gaap:ScheduleOfCreditLossesRelatedToFinancingReceivablesCurrentAndNoncurrentTableTextBlock
| Schedule of Credit Losses Related to Financing Receivables, Current and Noncurrent [Table Text Block] (Deprecated 2019-01-31) |
| us-gaap:ScheduleOfCreditLossesRelatedToFinancingReceivablesCurrentAndNoncurrentTableTextBlock |
| Tabular disclosure of the activity in the total allowance for credit losses related to financing receivables (such as loans or lease receivables) for entities that have an unclassified balance sheet, including the balance in the allowance at the beginning and end of each period, additions charged to operations, direct write-downs charged against the allowance, and recoveries of amounts previously charged off. |
| cm:Concept |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfCreditLossesRelatedToFinancingReceivablesCurrentAndNoncurrentTableTextBlock |
| CreditLossesRelatedToFinancingReceivablesCurrentAndNoncurrent |