XML 55 R44.htm IDEA: XBRL DOCUMENT
v3.23.1

LOANS AND ALLOWANCE FOR LOAN LOSSES - Modifications (Details) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2023 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | $ 277
Weighted-average term extension (in months) | 60 months
Commercial Mortgages |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | $ 277
% of Loan Class | 0.03%
Weighted-average interest rate reduction (%) | 0.00%
Principal Reduction |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | $ 0
Principal Reduction (in thousands) | 0
Principal Reduction | Commercial Mortgages |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | 0
Interest Rate Reduction |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | 0
Interest Rate Reduction | Commercial Mortgages |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | 0
Term Extension |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | 277
Term Extension | Commercial Mortgages |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | 277
Combination |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | 0
Combination | Commercial Mortgages |
Financing Receivable, Troubled Debt Restructuring [Line Items] |
Amortized cost basis | $ 0

X
- Definition Financing Receivable, Excluding Accrued Interest, Modified, Accumulated + References No definition available. + Details
Name: | chmg_FinancingReceivableExcludingAccruedInterestModifiedAccumulated
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount + References No definition available. + Details
Name: | chmg_FinancingReceivableExcludingAccruedInterestModifiedInPeriodAmount
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Excluding Accrued Interest, Modified in Period, Term Extension + References No definition available. + Details
Name: | chmg_FinancingReceivableExcludingAccruedInterestModifiedInPeriodTermExtension
Namespace Prefix: | chmg_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage + References No definition available. + Details
Name: | chmg_FinancingReceivableExcludingAccruedInterestModifiedInPeriodToTotalFinancingReceivablesPercentage
Namespace Prefix: | chmg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification + References No definition available. + Details
Name: | chmg_FinancingReceivableModifiedWeightedAverageInterestRateDecreaseFromModification
Namespace Prefix: | chmg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_PrincipalForgivenessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_ContractualInterestRateReductionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_ExtendedMaturityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=chmg_CombinationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |