cm:Concept: us-gaap:UnbilledReceivablesNotBillableAmountExpectedToBeCollectedAfterNextRollingTwelveMonths
| Unbilled Receivables, Not Billable, Amount Expected to be Collected after Next Rolling Twelve Months |
| us-gaap:UnbilledReceivablesNotBillableAmountExpectedToBeCollectedAfterNextRollingTwelveMonths |
| Amount of receivables under long-term contracts that have not been billed and were not billable that are expected to be collected after the next 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) |
| Debit |
| false |
| us-gaap:UnbilledReceivablesNotBillableAmountExpectedToBeCollectedAfterNextRollingTwelveMonths |