cm:Concept: us-gaap:UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
| Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations |
| us-gaap:UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations |
| Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations |