cm:Concept: us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseScheduleDiscussion
| Liability for Unpaid Claims and Claims Adjustment Expense Schedule, Discussion |
| us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseScheduleDiscussion |
| Discussion accompanying a schedule reflecting the financial activity during the period in the reserves for unpaid claims and claims adjustment expense. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseScheduleDiscussion |