XML 48 R37.htm IDEA: XBRL DOCUMENT
v3.22.2

ACQUISITIONS - Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Certain Loans Acquired During The Period [Abstract] |  |  |  |
Merger and acquisition integration related (recoveries) expenses | $ 3,960 | $ 4 | $ 4,259 | $ 31
NuVantage Insurance Corporation [Member] | Other intangibles | Second Acquisition of 2022 One Group |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  |  | 8 years |
NuVantage Insurance Corporation [Member] | Other intangibles | Third Acquisition of 2022 One Group |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  |  | 10 years |
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Other intangibles |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  |  | 15 years |
Thomas Gregory Associates [Member] | Other intangibles |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
Intangible asset useful life (amortization period) |  |  | 13 years |
Elmira Savings Bank [Member] |  |  |  |
Finite-Lived Intangible Assets, Net [Abstract] |  |  |  |
FHLB Borrowings | $ 17,600 |  | $ 17,600 |
Weighted-average rate | 2.48% |  | 2.48% |

X
- Definition N/A + References No definition available. + Details
Name: | cbu_CertainLoansAcquiredDuringPeriodAbstract
Namespace Prefix: | cbu_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI https://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460 + Details
Name: | us-gaap_BusinessCombinationAcquisitionRelatedCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
Name: | us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions. + References No definition available. + Details
Name: | us-gaap_FederalHomeLoanBankAdvances
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cbu_NuvantageInsuranceCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_OtherIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AssetAcquisitionAxis=cbu_SecondAcquisitionOf2022OneGroupMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AssetAcquisitionAxis=cbu_ThirdAcquisitionOf2022OneGroupMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cbu_FringeBenefitsDesignOfMinnesotaIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cbu_ThomasGregoryAssociatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cbu_ElmiraSavingsBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |