cm:Concept: us-gaap:CapitalLeasesNetInvestmentInDirectFinancingLeasesAccumulatedAmortization
| Capital Leases, Net Investment in Direct Financing Leases, Accumulated Amortization |
| us-gaap:CapitalLeasesNetInvestmentInDirectFinancingLeasesAccumulatedAmortization |
| Accumulated amortization of deferred income and initial direct costs pertaining to direct financing leases, which resulted from producing constant periodic rates of return on the net investments in the leases over their respective lease terms. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:CapitalLeasesNetInvestmentInDirectFinancingLeasesAccumulatedAmortization |