XML 47 R36.htm IDEA: XBRL DOCUMENT
v3.22.2

ACQUISITIONS - Summary of Loans Acquired (Details) - PCD Loans [Member] $ in Thousands | Jun. 30, 2022 USD ($)
--- | ---
Certain Loans Acquired During The Period [Abstract] |
Par value of loans at acquisition | $ 2,184
Allowance for credit losses at acquisition | (71)
Non-credit premium at acquisition | (81)
Fair value of acquired loans | $ 2,032

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 Allowance for credit losses at acquisition at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality. + References No definition available. + Details
Name: | cbu_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAllowanceForCreditLosses
Namespace Prefix: | cbu_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Par value of loans at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality. + References No definition available. + Details
Name: | cbu_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtParValue
Namespace Prefix: | cbu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Non-credit (discount) premium at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality. + References No definition available. + Details
Name: | cbu_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionNonCreditDiscountPremium
Namespace Prefix: | cbu_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value at acquisition of acquired loans. + References No definition available. + Details
Name: | cbu_FairValueOfLoansAcquiredDuringPeriodAtAcquisition
Namespace Prefix: | cbu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |