XML 69 R57.htm IDEA: XBRL DOCUMENT
v3.7.0.1

FAIR VALUE, Significant Unobservable Inputs (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2017 | Dec. 31, 2016
Other Real Estate Owned [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair value | $ 2,486 | $ 1,966
Other Real Estate Owned [Member] | Fair Value of Collateral [Member] | Minimum [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Estimated cost of disposal/market adjustment | 2.30% | 9.00%
Other Real Estate Owned [Member] | Fair Value of Collateral [Member] | Maximum [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Estimated cost of disposal/market adjustment | 96.00% | 97.00%
Other Real Estate Owned [Member] | Fair Value of Collateral [Member] | Weighted Average [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Estimated cost of disposal/market adjustment | 35.40% | 29.60%
Impaired Loans [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair value | $ 535 | $ 633
Impaired Loans [Member] | Fair Value of Collateral [Member] | Minimum [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Estimated cost of disposal/market adjustment | 9.00% | 15.00%
Impaired Loans [Member] | Fair Value of Collateral [Member] | Maximum [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Estimated cost of disposal/market adjustment | 43.00% | 50.00%
Impaired Loans [Member] | Fair Value of Collateral [Member] | Weighted Average [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Estimated cost of disposal/market adjustment | 26.00% | 36.50%
Commitments To Originate Real Estate Loans For Sale [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair value | $ 114 | $ 54
Commitments To Originate Real Estate Loans For Sale [Member] | Discounted Cash Flow [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Embedded servicing value | 1.00% | 1.00%

X
- Definition Embedded servicing value, used as an input to measure fair value. + References No definition available. + Details
Name: | cbu_FairValueInputsEmbeddedServicingValue
Namespace Prefix: | cbu_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Adjustment to the appraisal used to measure fair value for estimated cost of disposal or market adjustment. + References No definition available. + Details
Name: | cbu_FairValueInputsEstimatedCostOfDisposalOrMarketAdjustment
Namespace Prefix: | cbu_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + 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 (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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

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

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