cm:Concept: us-gaap:LeveragedLeasesEffectOfChangeInTaxRate
| Leveraged Leases, Effect of Change in Tax Rate |
| us-gaap:LeveragedLeasesEffectOfChangeInTaxRate |
| This item represents disclosure of the reasons for a significant variation from the customary relationship between income tax expense and pretax accounting income resulting from a change in tax rates affecting the accounting for leveraged leases when such variation is not otherwise apparent. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LeveragedLeasesEffectOfChangeInTaxRate |