XML 65 R38.htm IDEA: XBRL DOCUMENT
v2.4.1.9

LOANS AND ALLOWANCE FOR LOAN LOSSES, RECEIVABLES PAST DUE (Details) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2015 | Dec. 31, 2014
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Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | $ 1,128,004 us-gaap_FinancingReceivableRecordedInvestmentCurrent |  | $ 1,103,760 us-gaap_FinancingReceivableRecordedInvestmentCurrent |
30-89 Days Past Due | 4,329 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue |  | 8,731 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue |
90 Days or more Past Due and accruing | 1,476 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing |  | 1,454 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing |
Loans acquired with deteriorated credit quality | 2,017 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality |  | 2,631 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality |
Non-Accrual | 10,419 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus | [1] | 7,778 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus | [2]
Total | 1,146,245 us-gaap_NotesReceivableNet |  | 1,124,354 us-gaap_NotesReceivableNet |
Commercial and Agricultural [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |  | 620 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |
Total | 172,227 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |  | 166,820 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |
Commercial and Industrial [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 170,397 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 164,109 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
30-89 Days Past Due | 317 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 756 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
90 Days or more Past Due and accruing | 24 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 620 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
Non-Accrual | 331 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember | [1] | 312 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember | [2]
Total | 171,069 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 165,797 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
Agricultural [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 1,158 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 1,023 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |
30-89 Days Past Due | 0 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 0 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |
Non-Accrual | 0 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember | [1] | 0 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember | [2]
Total | 1,158 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 1,023 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |
Commercial Mortgages [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Loans acquired with deteriorated credit quality | 1,761 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |  | 1,761 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Total | 481,488 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |  | 453,719 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Construction [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 47,913 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 53,371 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
30-89 Days Past Due | 0 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 0 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
90 Days or more Past Due and accruing | 1,444 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 1,446 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Non-Accrual | 148 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | [1] | 150 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | [2]
Total | 49,505 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 54,967 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Commercial mortgages [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 424,367 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 391,096 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
30-89 Days Past Due | 536 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 3,064 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
Loans acquired with deteriorated credit quality | 1,761 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 1,761 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
Non-Accrual | 5,319 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | [1] | 2,831 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | [2]
Total | 431,983 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 398,752 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
Residential mortgages [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 193,684 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 191,089 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
30-89 Days Past Due | 1,482 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 2,333 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Loans acquired with deteriorated credit quality | 256 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 250 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Non-Accrual | 3,705 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | [1] | 3,615 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | [2]
Total | 199,127 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 197,287 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Consumer Loans [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember |
Total | 293,403 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember |  | 306,528 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember |
Credit cards [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 1,505 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 1,641 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |
30-89 Days Past Due | 13 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 5 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |
90 Days or more Past Due and accruing | 8 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 8 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |
Non-Accrual | 0 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember | [1] | 0 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember | [2]
Total | 1,526 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 1,654 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |
Home equity lines and loans [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 97,626 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 98,340 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
30-89 Days Past Due | 672 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 736 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
Non-Accrual | 655 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember | [1] | 515 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember | [2]
Total | 98,953 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 99,591 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
Indirect consumer loans [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 172,573 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 183,103 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
30-89 Days Past Due | 1,266 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 1,789 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
Non-Accrual | 249 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember | [1] | 325 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember | [2]
Total | 174,088 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 185,217 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
Direct consumer loans [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 18,781 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | 19,988 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |
30-89 Days Past Due | 43 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | 48 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |
Loans acquired with deteriorated credit quality | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | 0 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |
Non-Accrual | 12 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember | [1] | 30 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember | [2]
Total | $ 18,836 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | $ 20,066 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |
[1] | Includes all loans on non-accrual status regardless of the number of days such loans were delinquent as of March 31,2015.
[2] | Includes all loans on non-accrual status regardless of the number of days such loans were delinquent as of December 31, 2014.

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- Definition Financing receivables that are less than 90 days past due but more than 29 days past due. + References No definition available. + Details
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- Definition The balance of financing receivables that were acquired with deteriorated credit quality. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524 + Details
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- Definition Recorded investment in financing receivables that are 90 days or more past due and still accruing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5111-111524 + Details
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- Definition Financing receivables that are current. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524 + Details
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- Definition Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5111-111524 + Details
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- Definition Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3 -Article 5 + Details
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