cm:Concept: us-gaap:PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFive
| Present Value of Future Insurance Profits, Amortization Expense, Year Five |
| us-gaap:PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFive |
| Amount of amortization expense expected to be recognized during fifth fiscal year following latest fiscal year for present value of future profits of insurance contract acquired in business combination. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFive |