XML 81 R69.htm IDEA: XBRL DOCUMENT
v3.25.2

COMMITMENTS AND CONTINGENCIES - Contractual Amounts of Financial Instruments (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Commitments to make loans | Fixed Rate |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | $ 13,602 | $ 12,025
Commitments to make loans | Variable Rate |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 52,151 | 67,501
Unused lines of credit | Fixed Rate |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 6,524 | 4,484
Unused lines of credit | Variable Rate |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 383,762 | 355,872
Standby letters of credit | Fixed Rate |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | 0 | 0
Standby letters of credit | Variable Rate |  |
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |  |
Contractual amounts of financial instruments with off-balance sheet risk | $ 18,526 | $ 19,180

X
- Definition The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 825 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478898/942-825-50-1 + Details
Name: | us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommitmentsToExtendCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=chmg_FixedInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=chmg_VariableInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_UnusedLinesOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |