cm:Member: us-gaap:SifmaMunicipalSwapRateMember
| SIFMA Municipal Swap Rate [Member] |
| us-gaap:SifmaMunicipalSwapRateMember |
| Fixed rate on US dollar, constant-notional interest rate swap with its variable-rate leg referenced to Securities Industry and Financial Markets Association (SIFMA) Municipal Swap Index with no additional spread over SIFMA Municipal Swap Index on its variable-rate leg. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:SifmaMunicipalSwapRateMember |