cm:Concept: us-gaap:ActualSavingsAnticipatedByPreviousExitPlanNotAchievedAsExpectedOutcomeAndReasons
| Actual Savings Anticipated by Previous Exit Plan Not Achieved as Expected, Outcome and Reasons |
| us-gaap:ActualSavingsAnticipatedByPreviousExitPlanNotAchievedAsExpectedOutcomeAndReasons |
| If actual savings anticipated by the exit plan are not achieved as expected or are achieved in periods other than as expected, this element describes that outcome and its reasons. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ActualSavingsAnticipatedByPreviousExitPlanNotAchievedAsExpectedOutcomeAndReasons |