cm:Concept: us-gaap:EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent
| Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Percent |
| us-gaap:EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent |
| Percentage of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to Tax Cuts and Jobs Act. |
| cm:Concept |
| Pure (xbrli:pureItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent |