XML 58 R46.htm IDEA: XBRL DOCUMENT
v3.10.0.1

LOANS, Amount of Business Lending Loans by Credit Quality Category (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | $ 6,238,009 | $ 6,256,757
Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 4,816,142 | 4,619,663
Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,421,867 | 1,637,094
Business Lending [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 2,384,629 | 2,424,223
Business Lending [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,492,688 | 1,376,599
Business Lending [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 891,941 | 1,047,624
Business Lending [Member] | Pass [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 2,107,107 | 2,134,137
Business Lending [Member] | Pass [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,302,009 | 1,170,156
Business Lending [Member] | Pass [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 805,098 | 963,981
Business Lending [Member] | Special Mention [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 161,717 | 166,397
Business Lending [Member] | Special Mention [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 114,305 | 129,076
Business Lending [Member] | Special Mention [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 47,412 | 37,321
Business Lending [Member] | Classified [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 107,976 | 111,995
Business Lending [Member] | Classified [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 76,147 | 77,367
Business Lending [Member] | Classified [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 31,829 | 34,628
Business Lending [Member] | Doubtful [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,825 | 1,579
Business Lending [Member] | Doubtful [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 227 | 0
Business Lending [Member] | Doubtful [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,598 | 1,579
Business Lending [Member] | Acquired Impaired [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 6,004 | 10,115
Business Lending [Member] | Acquired Impaired [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 0 | 0
Business Lending [Member] | Acquired Impaired [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 6,004 | 10,115
All Other Loans [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 3,323,454 | 3,243,064
All Other Loans [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 529,926 | 589,470
All Other Loans [Member] | Performing [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 3,310,186 | 3,229,051
All Other Loans [Member] | Performing [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 525,295 | 584,874
All Other Loans [Member] | Nonperforming [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 13,268 | 14,013
All Other Loans [Member] | Nonperforming [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 4,631 | 4,596
Consumer Mortgage [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,783,564 | 1,754,609
Consumer Mortgage [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 426,487 | 465,689
Consumer Mortgage [Member] | Performing [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,772,046 | 1,742,387
Consumer Mortgage [Member] | Performing [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 423,308 | 462,597
Consumer Mortgage [Member] | Nonperforming [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 11,518 | 12,222
Consumer Mortgage [Member] | Nonperforming [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 3,179 | 3,092
Consumer Indirect [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,048,768 | 991,836
Consumer Indirect [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 14,911 | 20,142
Consumer Indirect [Member] | Performing [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,048,639 | 991,541
Consumer Indirect [Member] | Performing [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 14,876 | 20,134
Consumer Indirect [Member] | Nonperforming [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 129 | 295
Consumer Indirect [Member] | Nonperforming [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 35 | 8
Consumer Direct [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 177,294 | 174,479
Consumer Direct [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 3,923 | 5,450
Consumer Direct [Member] | Performing [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 177,274 | 174,431
Consumer Direct [Member] | Performing [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 3,923 | 5,450
Consumer Direct [Member] | Nonperforming [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 20 | 48
Consumer Direct [Member] | Nonperforming [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 0 | 0
Home Equity [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 313,828 | 322,140
Home Equity [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 84,605 | 98,189
Home Equity [Member] | Performing [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 312,227 | 320,692
Home Equity [Member] | Performing [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 83,188 | 96,693
Home Equity [Member] | Nonperforming [Member] | Legacy Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | 1,601 | 1,448
Home Equity [Member] | Nonperforming [Member] | Acquired Loans [Member] |  |
Business Lending Loans by Credit Quality Category [Abstract] |  |
Loans | $ 1,417 | $ 1,496

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

X
- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=cbu_LegacyLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=cbu_AcquiredLoansMember
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_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_DoubtfulMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=cbu_PurchasedImpairedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_PerformingFinancingReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_NonperformingFinancingReceivableMember
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: |