cm:Axis: us-gaap:RegulatoryCapitalRequirementsForMortgageCompaniesBySecondaryMarketInvestorAxis
| Regulatory Capital Requirements for Mortgage Companies, by Secondary Market Investor [Axis] |
| us-gaap:RegulatoryCapitalRequirementsForMortgageCompaniesBySecondaryMarketInvestorAxis |
| The entity's required and actual net worth amounts as of the balance sheet date, by secondary market investor. |
| cm:Axis |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:RegulatoryCapitalRequirementsForMortgageCompaniesBySecondaryMarketInvestorAxis |