XML 50 R38.htm IDEA: XBRL DOCUMENT
v3.8.0.1

LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowances (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Dec. 31, 2016
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | $ 15,104 | $ 14,668 | $ 14,253 | $ 14,260 |  |
Charge-offs | (816) | (443) | (1,708) | (1,233) |  |
Recoveries | 117 | 50 | 399 | 265 |  |
Net recoveries (charge-offs) | (699) | (393) | (1,309) | (968) |  |
Provision | 1,289 | 1,050 | 2,750 | 2,033 |  |
Ending balance | 15,694 | 15,325 | 15,694 | 15,325 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  | $ 1,168 | $ 876
Collectively evaluated for impairment |  |  |  |  | 14,497 | 13,293
Total ending allowance balance | 15,104 | 14,668 | 14,253 | 14,260 | 15,694 | 14,253
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  | 11,092 | 11,926
Loans collectively evaluated for impairment |  |  |  |  | 1,280,337 | 1,190,138
Total ending loans balance |  |  |  |  | 1,292,261 | 1,203,482
Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  | 84 |  |  |
Ending balance | 29 |  | 29 |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 29 |  | 84 |  | 29 | 84
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  |  | 832 | 1,418
Commercial and agricultural: |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 1,883 | 1,771 | 1,589 | 1,831 |  |
Charge-offs | (89) | (104) | (96) | (121) |  |
Recoveries | 34 | 15 | 95 | 65 |  |
Net recoveries (charge-offs) | (55) | (89) | (1) | (56) |  |
Provision | 99 | 101 | 339 | 8 |  |
Ending balance | 1,927 | 1,783 | 1,927 | 1,783 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  | 159 | 0
Collectively evaluated for impairment |  |  |  |  | 1,768 | 1,589
Total ending allowance balance | 1,883 | 1,771 | 1,589 | 1,831 | 1,927 | 1,589
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  | 1,133 | 693
Loans collectively evaluated for impairment |  |  |  |  | 188,170 | 176,334
Total ending loans balance |  |  |  |  | 189,303 | 177,027
Commercial and agricultural: | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  | 0 |  |  |
Ending balance | 0 |  | 0 |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 0 |  | 0 |  | 0 | 0
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  |  | 0 | 0
Commercial Mortgages |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 7,778 | 7,754 | 7,270 | 7,112 |  |
Charge-offs | (154) | (52) | (154) | (52) |  |
Recoveries | 1 | 1 | 4 | 10 |  |
Net recoveries (charge-offs) | (153) | (51) | (150) | (42) |  |
Provision | 758 | 520 | 1,263 | 1,153 |  |
Ending balance | 8,383 | 8,223 | 8,383 | 8,223 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  | 1,009 | 735
Collectively evaluated for impairment |  |  |  |  | 7,345 | 6,476
Total ending allowance balance | 7,778 | 7,754 | 7,270 | 7,112 | 8,383 | 7,270
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  | 9,458 | 10,382
Loans collectively evaluated for impairment |  |  |  |  | 629,211 | 558,451
Total ending loans balance |  |  |  |  | 639,501 | 570,156
Commercial Mortgages | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  | 59 |  |  |
Ending balance | 29 |  | 29 |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 29 |  | 59 |  | 29 | 59
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  |  | 832 | 1,323
Residential mortgages |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 1,517 | 1,504 | 1,523 | 1,464 |  |
Charge-offs | (133) | (7) | (193) | (65) |  |
Recoveries | 0 | 0 | 30 | 0 |  |
Net recoveries (charge-offs) | (133) | (7) | (163) | (65) |  |
Provision | 12 | 50 | 36 | 148 |  |
Ending balance | 1,396 | 1,547 | 1,396 | 1,547 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  | 0 | 0
Collectively evaluated for impairment |  |  |  |  | 1,396 | 1,498
Total ending allowance balance | 1,517 | 1,504 | 1,523 | 1,464 | 1,396 | 1,523
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  | 434 | 396
Loans collectively evaluated for impairment |  |  |  |  | 197,267 | 198,474
Total ending loans balance |  |  |  |  | 197,701 | 198,965
Residential mortgages | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  | 25 |  |  |
Ending balance | 0 |  | 0 |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 0 |  | 25 |  | 0 | 25
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  |  | 0 | 95
Consumer loans: |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 3,926 | 3,639 | 3,871 | 3,853 |  |
Charge-offs | (440) | (280) | (1,265) | (995) |  |
Recoveries | 82 | 34 | 270 | 190 |  |
Net recoveries (charge-offs) | (358) | (246) | (995) | (805) |  |
Provision | 420 | 379 | 1,112 | 724 |  |
Ending balance | 3,988 | 3,772 | 3,988 | 3,772 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  | 0 | 141
Collectively evaluated for impairment |  |  |  |  | 3,988 | 3,730
Total ending allowance balance | 3,926 | $ 3,639 | 3,871 | $ 3,853 | 3,988 | 3,871
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  | 67 | 455
Loans collectively evaluated for impairment |  |  |  |  | 265,689 | 256,879
Total ending loans balance |  |  |  |  | 265,756 | 257,334
Consumer loans: | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  | 0 |  |  |
Ending balance | 0 |  | 0 |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | $ 0 |  | $ 0 |  | 0 | 0
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  |  | $ 0 | $ 0

X
- References No definition available. + Details
Name: | chmg_FinancingReceivableAllowanceForCreditLossesIndividuallyAndCollectivelyEvaluatedForImpairmentAbstract
Namespace Prefix: | chmg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of recovery of (write-downs of) financing receivables doubtful of collection. + References No definition available. + Details
Name: | chmg_FinancingReceivableAllowanceForCreditLossesNetChargeOff
Namespace Prefix: | chmg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | chmg_FinancingReceivableAllowanceForFinanceReceivableEvaluatedForImpairmentAbstract
Namespace Prefix: | chmg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition A valuation allowance for financing receivables that are expected to be uncollectible. + 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 (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + 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 (g) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + 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 (g) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of recovery of financing receivables doubtful of collection that were previously charged off. + 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 (c)(4) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of direct write-downs of financing receivables charged against the allowance. + 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 (c)(3) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The balance of financing receivables that were collectively evaluated for impairment. + 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=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The balance of financing receivables that were individually evaluated for impairment. + 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=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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 + Details
Name: | us-gaap_NotesReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of expense related to estimated loss from loan and lease transactions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.11) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_ProvisionForLoanAndLeaseLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_ReceivablesAcquiredWithDeterioratedCreditQualityAxis=us-gaap_ReceivablesAcquiredWithDeterioratedCreditQualityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
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: |