cm:Member: us-gaap:FederalFundsEffectiveSwapRateMember
| Fed Funds Effective Rate Overnight Index Swap Rate [Member] |
| us-gaap:FederalFundsEffectiveSwapRateMember |
| Fixed rate on U.S. dollar, constant-notional interest rate swap having its variable-rate leg referenced to Federal Funds effective rate with no additional spread over Federal Funds effective rate on that variable-rate leg. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:FederalFundsEffectiveSwapRateMember |