cm:Concept: us-gaap:CertainLoansAndDebtSecuritiesAcquiredInTransferDescriptionOfHowPrepaymentsAreConsideredInDeterminationOfContractualCashFlowsAndCashFlowsExpectedToBeCollected
| Certain Loans and Debt Securities Acquired in Transfer, Description of how Prepayments are Considered in Determination of Contractual Cash Flows and Cash Flows Expected to be Collected |
| us-gaap:CertainLoansAndDebtSecuritiesAcquiredInTransferDescriptionOfHowPrepaymentsAreConsideredInDeterminationOfContractualCashFlowsAndCashFlowsExpectedToBeCollected |
| Description of how prepayments are considered in determination of contractual cash flows and cash flows expected to be collected for the loan or debt security. This relates to loans and debt securities for which at acquisition it was probable that the investor would be unable to collect all contractually required payments receivable or all cash flows expected at acquisition. |
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| Text/String (xbrli:stringItemType) |
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| us-gaap:CertainLoansAndDebtSecuritiesAcquiredInTransferDescriptionOfHowPrepaymentsAreConsideredInDeterminationOfContractualCashFlowsAndCashFlowsExpectedToBeCollected |