cm:Concept: us-gaap:DebtConversionConvertedInstrumentExpirationOrDueDateDayMonthAndYear
| Debt Conversion, Converted Instrument, Expiration or Due Date |
| us-gaap:DebtConversionConvertedInstrumentExpirationOrDueDateDayMonthAndYear |
| Expiration, mandatory redemption, or due date, in CCYY-MM-DD format, of the financial instrument issued in exchange for the original debt being converted in a noncash or part noncash transaction. |
| cm:Concept |
| Date (xbrli:dateItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DebtConversionConvertedInstrumentExpirationOrDueDateDayMonthAndYear |