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