XML 93 R58.htm IDEA: XBRL DOCUMENT
v2.4.1.9

LOANS AND ALLOWANCE FOR LOAN LOSSES, RECEIVABLES PAST DUE (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013
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Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | $ 1,103,760 us-gaap_FinancingReceivableRecordedInvestmentCurrent |  | $ 970,708 us-gaap_FinancingReceivableRecordedInvestmentCurrent |
30-89 Days Past Due | 8,731 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue |  | 8,069 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue |
90 Days or more Past Due and accruing | 1,454 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing |  | 1,473 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing |
Loans acquired with deteriorated credit quality | 2,631 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality |  | 9,696 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality |
Non-Accrual | 7,778 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus | [1] | 8,517 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus | [2]
Total | 1,124,354 us-gaap_NotesReceivableNet |  | 998,463 us-gaap_NotesReceivableNet |
Commercial and Agricultural [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Loans acquired with deteriorated credit quality | 620 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |  | 678 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |
Total | 166,820 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |  | 145,732 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndAgriculturalPortfolioSegmentMember |
Commercial and Industrial [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 164,109 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 143,100 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
30-89 Days Past Due | 756 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 29 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
90 Days or more Past Due and accruing | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 0 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
Loans acquired with deteriorated credit quality | 620 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 678 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
Non-Accrual | 312 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember | [1] | 1,348 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember | [2]
Total | 165,797 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |  | 145,155 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_CommercialAndIndustrialMember |
Agricultural [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 1,023 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 577 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 | 1,023 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_AgriculturalMember |  | 577 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 |  | 8,757 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Total | 453,719 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |  | 374,096 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Construction [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 53,371 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 24,742 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 | 1,446 us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 1,454 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 |  | 774 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Non-Accrual | 150 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | [1] | 540 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | [2]
Total | 54,967 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |  | 27,510 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Commercial Mortgages [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 391,096 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 335,123 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
30-89 Days Past Due | 3,064 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 1,138 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 |  | 7,983 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
Non-Accrual | 2,831 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | [1] | 2,342 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | [2]
Total | 398,752 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |  | 346,586 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember |
Residential Mortgages [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 191,089 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 187,448 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
30-89 Days Past Due | 2,333 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 5,458 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 | 250 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 261 us-gaap_FinancingReceivableAcquiredWithDeterioratedCreditQuality / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Non-Accrual | 3,615 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | [1] | 3,358 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | [2]
Total | 197,287 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |  | 196,525 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 | 306,528 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember |  | 282,110 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember |
Credit Cards [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 1,641 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 1,729 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |
30-89 Days Past Due | 5 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 9 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 |  | 19 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 | 1,654 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerCreditCardFinancingReceivableMember |  | 1,757 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 | 98,340 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 95,349 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
30-89 Days Past Due | 736 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 150 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 | 515 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember | [1] | 635 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember | [2]
Total | 99,591 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |  | 96,134 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_HomeEquityLinesAndLoansMember |
Indirect Consumer Loans [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 183,103 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 163,810 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
30-89 Days Past Due | 1,789 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 1,235 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 | 325 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember | [1] | 249 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember | [2]
Total | 185,217 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |  | 165,294 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = chmg_IndirectConsumerLoansMember |
Direct Consumer Loans [Member] |  |  |  |
Aging of the recorded investment in loans past due [Abstract] |  |  |  |
Current | 19,988 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | 18,830 us-gaap_FinancingReceivableRecordedInvestmentCurrent / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |
30-89 Days Past Due | 48 chmg_FinancingReceivableRecordedInvestment30To89DaysPastDue / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | 50 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 | 30 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember | [1] | 45 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember | [2]
Total | $ 20,066 us-gaap_NotesReceivableNet / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerOtherFinancingReceivableMember |  | $ 18,925 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 December 31, 2014.
[2] | Includes all loans on non-accrual status regardless of the number of days such loans were delinquent as of December 31, 2013.

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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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