XML 28 R44.htm IDEA: XBRL DOCUMENT
v3.3.0.814

FAIR VALUE, Quantitative Information (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014 | Dec. 31, 2014
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Impaired loan valuation allowance | $ 1,610 |  | $ 1,610 |  | $ 1,235
Increase (decrease) in provision for loan losses | 307 | $ 589 | 956 | $ 2,330 |
Impaired Loans [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Carrying amount of impaired loans | 5,100 |  | 5,100 |  | 4,900
Impaired loan valuation allowance | 1,600 |  | 1,600 |  | 1,200
Increase (decrease) in provision for loan losses | 77 |  | 331 |  | 232
Impaired Loans [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Third Party Appraisals [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Fair value | 3,481 |  | $ 3,481 |  | $ 3,645
Unobservable input |  |  | Appraisal adjustments by management for qualitative factors such as market conditions and collateral characteristics |  | Appraisal adjustments by management for qualitative factors such as market conditions and collateral characteristics
Impaired Loans [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Third Party Appraisals [Member] | Maximum [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Discount rate (in hundredths) |  |  | 100.00% |  | 100.00%
Impaired Loans [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Third Party Appraisals [Member] | Minimum [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Discount rate (in hundredths) |  |  | 0.00% |  | 0.00%
Other real estate owned [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Other real estate owned valuation allowance | 120 |  | $ 120 |  | $ 2
Other real estate owned expense associated with valuation allowance | 120 |  | 120 |  | 0
Outstanding balance of OREO | 2,500 |  | 2,500 |  | 3,100
Other real estate owned [Member] | Non-recurring [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Outstanding balance of OREO | 2,376 |  | 2,376 |  | 3,065
Other real estate owned [Member] | Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Outstanding balance of OREO | 0 |  | 0 |  | 0
Other real estate owned [Member] | Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Outstanding balance of OREO | 0 |  | 0 |  | 0
Other real estate owned [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Outstanding balance of OREO | 2,376 |  | 2,376 |  | 3,065
Other real estate owned [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Third Party Appraisals [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Fair value | $ 2,376 |  | $ 2,376 |  | $ 3,065
Unobservable input |  |  | Appraisal adjustments by management for qualitative factors such as market conditions and estimated liquidation expenses |  | Appraisal adjustments by management for qualitative factors such as market conditions and estimated liquidation expenses
Discount rate (in hundredths) |  |  | 31.00% |  |
Other real estate owned [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Third Party Appraisals [Member] | Maximum [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Discount rate (in hundredths) |  |  |  |  | 27.00%
Other real estate owned [Member] | Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Third Party Appraisals [Member] | Minimum [Member] |  |  |  |  |
Information related to Level 3 non-recurring fair value measurement [Abstract] |  |  |  |  |
Discount rate (in hundredths) |  |  |  |  | 7.00%

X
- Definition This item represents a description of the inputs and the information used to develop the inputs for fair value measurement using significant unobservable inputs (Level 3) as applied to the identified [major] category of asset or liability. + References No definition available. + Details
Name: | chmg_FairValueMeasurementsUnobservableInputsOneDescription
Namespace Prefix: | chmg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | chmg_InformationRelatedToLevel3NonRecurringFairValueMeasurementAbstract
Namespace Prefix: | chmg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosureNonrecurring
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueInputsDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of other real estate and foreclosed assets. Other real estate may include real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10(4)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_OtherRealEstateAndForeclosedAssets
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=56944662&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=49124121&loc=SL6953423-111524 + Details
Name: | us-gaap_ProvisionForLoanAndLeaseLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the valuation allowance for real estate owned that was applied in the period against the carrying amount of real estate owned that was sold, written down or written off. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10(4)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The valuation allowance loss on real estate owned or any impairment losses taken against real estate investments held for use or resale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 35 -Paragraph 43 -URI http://asc.fasb.org/extlink&oid=29634951&loc=d3e1739-110224 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.10(4)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 35 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=29634951&loc=d3e1424-110224 + Details
Name: | us-gaap_RealEstateOwnedValuationAllowanceComponent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=chmg_ImpairedLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=chmg_OtherRealEstateOwnedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |