cm:Level3TextBlock: us-gaap:DemutualizationByInsuranceEntityScheduleOfNatureAndTerms
| Demutualization by Insurance Entity, Schedule of Nature and Terms [Table Text Block] |
| us-gaap:DemutualizationByInsuranceEntityScheduleOfNatureAndTerms |
| The entire disclosure related to a demutualization by an insurance entity which might include the date; the plan of conversion or demutualization; description of the conversion from a mutual to a stock entity; the names of the entities involved including any changes in entity names, mergers or reorganizations; formation of a Mutual Insurance Holding entity (MIHC); policyholder compensation including an indication of the disposition of the membership interests (extinguished), a description of the consideration received by the policyholders (for example cash, stock and policy credits); the amount and nature of the costs of the demutualization; and the establishment of a closed block. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
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| us-gaap:DemutualizationByInsuranceEntityScheduleOfNatureAndTerms |