cm:Concept: us-gaap:RecordedUnconditionalPurchaseObligationDueInRollingAfterYearFive
| Recorded Unconditional Purchase Obligation, Due in Rolling after Year Five |
| us-gaap:RecordedUnconditionalPurchaseObligationDueInRollingAfterYearFive |
| Amount of the recorded unconditional purchase obligation maturing after the fifth 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:RecordedUnconditionalPurchaseObligationDueInRollingAfterYearFive |