cm:Concept: us-gaap:CapitalLeasesNetInvestmentInDirectFinancingLeasesDeferredIncome
| Capital Leases, Net Investment in Direct Financing Leases, Deferred Income |
| us-gaap:CapitalLeasesNetInvestmentInDirectFinancingLeasesDeferredIncome |
| The remaining (unamortized) difference between the gross investment in a direct financing lease and the cost or carrying amount, if different, of the leased property as of the balance sheet date. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:CapitalLeasesNetInvestmentInDirectFinancingLeasesDeferredIncome |