cm:Member: us-gaap:LondonInterbankOfferedRateLiborSwapRateMember
| London Interbank Offered Rate (LIBOR) Swap Rate [Member] |
| us-gaap:LondonInterbankOfferedRateLiborSwapRateMember |
| Fixed rate on single-currency, constant-notional interest rate swap that has its variable-rate leg referenced to London Interbank Offered Rate (LIBOR) with no additional spread on variable-rate leg. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:LondonInterbankOfferedRateLiborSwapRateMember |