XML 77 R61.htm IDEA: XBRL DOCUMENT
v3.24.0.1

LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loan Summary (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Loans receivable, net |  |  |  |
Loans | $ 9,704,598 | $ 8,809,394 |  |
Allowance for credit losses | (66,669) | (61,059) | $ (50,672) |
Loans, net of allowance for credit losses | 9,637,929 | 8,748,335 |  |
Net deferred loan origination costs | 81,600 | 73,800 |  |
Loans receivable, related parties |  |  |  |
Balance at beginning of year | 12,373 | 13,773 |  |
New loans | 1,372 | 2,025 |  |
Payments | (2,053) | (3,425) |  |
Balance at end of year | 11,692 | 12,373 | 13,773 |
CRE - multifamily |  |  |  |
Loans receivable, net |  |  |  |
Loans | 619,794 | 484,773 |  |
CRE - owner occupied |  |  |  |
Loans receivable, net |  |  |  |
Loans | 752,774 | 722,387 |  |
CRE - non-owner occupied |  |  |  |
Loans receivable, net |  |  |  |
Loans | 1,711,198 | 1,431,720 |  |
Commercial & industrial and other business loans |  |  |  |
Loans receivable, net |  |  |  |
Loans | 1,000,630 | 1,006,785 |  |
Business lending |  |  |  |
Loans receivable, net |  |  |  |
Loans | 4,084,396 | 3,645,665 |  |
Consumer mortgage |  |  |  |
Loans receivable, net |  |  |  |
Loans | 3,285,018 | 3,012,475 |  |
Consumer indirect |  |  |  |
Loans receivable, net |  |  |  |
Loans | 1,703,440 | 1,539,653 |  |
Consumer direct |  |  |  |
Loans receivable, net |  |  |  |
Loans | 185,229 | 177,605 |  |
Home equity |  |  |  |
Loans receivable, net |  |  |  |
Loans | 446,515 | 433,996 |  |
Unallocated |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses |  |  | (1,000) |
Commercial Portfolio Segment |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses |  |  |  | $ (62,358)
Commercial Portfolio Segment | CRE - multifamily |  |  |  |
Loans receivable, net |  |  |  |
Loans | 619,794 | 484,773 |  |
Commercial Portfolio Segment | CRE - owner occupied |  |  |  |
Loans receivable, net |  |  |  |
Loans | 752,774 | 722,387 |  |
Commercial Portfolio Segment | CRE - non-owner occupied |  |  |  |
Loans receivable, net |  |  |  |
Loans | 1,711,198 | 1,431,720 |  |
Commercial Portfolio Segment | Commercial & industrial and other business loans |  |  |  |
Loans receivable, net |  |  |  |
Loans | 1,000,630 | 1,006,785 |  |
Commercial Portfolio Segment | Business lending |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses |  | (23,297) | (22,995) | (30,072)
Commercial Portfolio Segment | Unallocated |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses |  |  |  | (1,000)
Residential Portfolio Segment | Consumer mortgage |  |  |  |
Loans receivable, net |  |  |  |
Loans | 3,285,018 | 3,012,475 |  |
Allowance for credit losses | (15,333) | (14,343) | (10,017) | (10,672)
Residential Portfolio Segment | Home equity |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses | (1,628) | (1,594) | (1,814) | (2,222)
Consumer Portfolio Segment | Business lending |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses | (26,854) | (23,297) |  |
Consumer Portfolio Segment | Consumer indirect |  |  |  |
Loans receivable, net |  |  |  |
Loans | 1,703,440 | 1,539,653 |  |
Allowance for credit losses | (18,585) | (17,852) | (11,737) | (13,696)
Consumer Portfolio Segment | Consumer direct |  |  |  |
Loans receivable, net |  |  |  |
Loans | 185,229 | 177,605 |  |
Allowance for credit losses | (3,269) | (2,973) | (2,306) | $ (3,207)
Consumer Portfolio Segment | Home equity |  |  |  |
Loans receivable, net |  |  |  |
Loans | 446,515 | 433,996 |  |
Total Allowances For Credit Losses |  |  |  |
Loans receivable, net |  |  |  |
Allowance for credit losses | $ (67,582) | $ (62,182) | $ (50,672) |

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unamortized loan commitment, origination, and other costs (fees) and purchase premium (discount) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481598/310-20-45-1 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 3 -SubTopic 20 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481569/310-20-50-3 + Details
Name: | us-gaap_FinancingReceivableUnamortizedLoanCommitmentOriginationFeeAndPremiumDiscount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483326/850-10-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(e)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
Name: | us-gaap_LoansAndLeasesReceivableRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Reflects the amount of new advances made to related parties in the form of loan and lease receivables. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483326/850-10-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(e)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
Name: | us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash inflow from related parties which reduce the amount of loans and leases receivable due from related parties. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 12 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-12 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)(e)(1)(i)) -SubTopic 210 -Topic 942 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
Name: | us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_LoansAndLeasesReceivableRelatedPartiesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_CommercialRealEstateMultifamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_CommercialRealEstateOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_CommercialRealEstateNonOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_CommercialIndustrialAndOtherBusinessLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_ConsumerInstallmentIndirectMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_ConsumerInstallmentDirectMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_HomeEquityReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_UnallocatedFinancingReceivablesMember
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: |

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