XML 57 R45.htm IDEA: XBRL DOCUMENT
v3.25.1

LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loan Portfolio (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024 | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | --- | --- | ---
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | $ 2,097,636 | $ 2,071,419 |  |
Allowance for credit losses | (22,522) | (21,388) | $ (20,471) | $ (22,517)
Loans, net | 2,075,114 | 2,050,031 |  |
Commercial Mortgages |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 1,260,256 | 1,217,004 |  |
Allowance for credit losses | (12,089) | (11,214) | (10,367) | (12,026)
Loans, net |  |  | 1,900 |
Commercial Mortgages | Construction |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 95,671 | 94,943 |  |
Commercial Mortgages | Owner occupied commercial real estate |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 155,027 | 142,279 |  |
Commercial Mortgages | Non-owner occupied commercial real estate |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 1,009,558 | 979,782 |  |
Residential Mortgages |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 275,448 | 274,979 |  |
Allowance for credit losses | (2,473) | (2,259) | (2,062) | (2,194)
Consumer Loans |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 266,200 | 279,915 |  |
Allowance for credit losses | (2,807) | (3,395) | $ (3,526) | $ (3,242)
Consumer Loans | Home equity lines and loans |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 93,914 | 93,220 |  |
Consumer Loans | Indirect consumer loans |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 164,594 | 178,118 |  |
Consumer Loans | Direct consumer loans |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | 7,692 | 8,577 |  |
Commercial and industrial |  |  |  |
Composition of loan portfolio [Abstract] |  |  |  |
Total loans, net of deferred loan fees and costs | $ 295,732 | $ 299,521 |  |

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_LoansAndLeasesReceivableNetOfDeferredIncomeAbstract
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_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=chmg_OwnerOccupiedCommercialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=chmg_NonOwnerOccupiedCommercialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=chmg_HomeEquityLinesAndLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=chmg_IndirectConsumerLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=chmg_DirectConsumerLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_CommercialAndIndustrialSectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |