cm:Concept: us-gaap:RecordedUnconditionalPurchaseObligationDueInRollingYearFour
| Recorded Unconditional Purchase Obligation, Due in Rolling Year Four |
| us-gaap:RecordedUnconditionalPurchaseObligationDueInRollingYearFour |
| Amount of the recorded unconditional purchase obligation maturing in the fourth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:RecordedUnconditionalPurchaseObligationDueInRollingYearFour |