cm:Level3TextBlock: us-gaap:ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock
| Schedule of Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] |
| us-gaap:ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock |
| Tabular disclosure of the reasons for the change in incurred claims and claim adjustment expenses recognized in the income statement attributable to insured events of prior fiscal years. Also includes disclosures of additional premiums or return premiums accrued as a result of changes in incurred claims and claim adjustment expenses. |
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| us-gaap:ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock |