cm:Concept: us-gaap:PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFour
| Present Value of Future Insurance Profits, Amortization Expense, Year Four |
| us-gaap:PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFour |
| Amount of amortization expense expected to be recognized during fourth 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:PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFour |