cm:Concept: us-gaap:UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums
| Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums |
| us-gaap:UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums |
| Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums |