XML 22 R42.htm IDEA: XBRL DOCUMENT v2.4.1.9

LOANS, Troubled Debt Restructuring (TDR) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 Loan	Mar. 31, 2014 Loan	Dec. 31, 2014 Loan
Financing Receivable, Modifications [Line Items]
Individual commercial loan evaluated for impairment, minimum	$ 500,000us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
TDR included in general loan loss allocation and the qualitative review, maximum	500,000cbu_FinancingReceivableTDRCollectivelyEvaluatedForImpairmentMaximum
Troubled debt restructurings, Nonaccrual, Number of loans	66cbu_TroubledDebtRestructuringsNonaccrual		68cbu_TroubledDebtRestructuringsNonaccrual
Troubled debt restructurings, Nonaccrual amount	2,493,000cbu_TroubledDebtRestructuringsNonaccrualAmount		2,752,000cbu_TroubledDebtRestructuringsNonaccrualAmount
Troubled debt restructurings Accruing, Number of loans	149cbu_TroubledDebtRestructuringsAccruing		157cbu_TroubledDebtRestructuringsAccruing
Troubled debt restructurings, Accruing amount	3,086,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance		3,200,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance
Troubled Debt Restructurings, Total number of loans	215cbu_TroubledDebtRestructurings		225cbu_TroubledDebtRestructurings
Troubled debt restructurings, Total amount	5,579,000us-gaap_FinancingReceivableModificationsRecordedInvestment		5,952,000us-gaap_FinancingReceivableModificationsRecordedInvestment
TDR occurring during the period, number of contracts	13us-gaap_FinancingReceivableModificationsNumberOfContracts2	30us-gaap_FinancingReceivableModificationsNumberOfContracts2
TDR occurring during the year, post-modification recorded investment	333,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	877,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Consumer Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings, Nonaccrual, Number of loans	49cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember		49cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
Troubled debt restructurings, Nonaccrual amount	2,059,000cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember		2,092,000cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
Troubled debt restructurings Accruing, Number of loans	36cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember		37cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
Troubled debt restructurings, Accruing amount	1,641,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember		1,770,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
Troubled Debt Restructurings, Total number of loans	85cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember		86cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
Troubled debt restructurings, Total amount	3,700,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember		3,862,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
TDR occurring during the period, number of contracts	4us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember	11us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
TDR occurring during the year, post-modification recorded investment	213,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember	533,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialMortgageMember
Business Lending [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings, Nonaccrual, Number of loans	4cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember		6cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
Troubled debt restructurings, Nonaccrual amount	307,000cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember		442,000cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
Troubled debt restructurings Accruing, Number of loans	3cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember		3cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
Troubled debt restructurings, Accruing amount	463,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember		468,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
Troubled Debt Restructurings, Total number of loans	7cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember		9cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
Troubled debt restructurings, Total amount	770,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember		910,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
TDR occurring during the period, number of contracts	0us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember	4us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
TDR occurring during the year, post-modification recorded investment	0us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember	192,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialLoanMember
Consumer Indirect [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings, Nonaccrual, Number of loans	0cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember		0cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
Troubled debt restructurings, Nonaccrual amount	0cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember		0cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
Troubled debt restructurings Accruing, Number of loans	75cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember		79cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
Troubled debt restructurings, Accruing amount	649,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember		615,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
Troubled Debt Restructurings, Total number of loans	75cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember		79cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
Troubled debt restructurings, Total amount	649,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember		615,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
TDR occurring during the period, number of contracts	7us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember	12us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
TDR occurring during the year, post-modification recorded investment	101,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember	112,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentIndirectMember
Consumer Direct [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings, Nonaccrual, Number of loans	0cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember		0cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
Troubled debt restructurings, Nonaccrual amount	0cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember		0cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
Troubled debt restructurings Accruing, Number of loans	22cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember		25cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
Troubled debt restructurings, Accruing amount	62,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember		69,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
Troubled Debt Restructurings, Total number of loans	22cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember		25cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
Troubled debt restructurings, Total amount	62,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember		69,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
TDR occurring during the period, number of contracts	1us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember	2us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
TDR occurring during the year, post-modification recorded investment	4,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember	10,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_ConsumerInstallmentDirectMember
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings, Nonaccrual, Number of loans	13cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember		13cbu_TroubledDebtRestructuringsNonaccrual / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
Troubled debt restructurings, Nonaccrual amount	127,000cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember		218,000cbu_TroubledDebtRestructuringsNonaccrualAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
Troubled debt restructurings Accruing, Number of loans	13cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember		13cbu_TroubledDebtRestructuringsAccruing / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
Troubled debt restructurings, Accruing amount	271,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember		278,000cbu_TroubledDebtRestructuringsAccruingCarryingBalance / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
Troubled Debt Restructurings, Total number of loans	26cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember		26cbu_TroubledDebtRestructurings / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
Troubled debt restructurings, Total amount	398,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember		496,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
TDR occurring during the period, number of contracts	1us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember	1us-gaap_FinancingReceivableModificationsNumberOfContracts2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember
TDR occurring during the year, post-modification recorded investment	$ 15,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember	$ 30,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = cbu_HomeEquityReceivablesMember

X

- Definition

The maximum balance of financing receivables that classify as a troubled debt restructure that were collectively evaluated for impairment.

+ References

No definition available.

+ Details

Name:	cbu_FinancingReceivableTDRCollectivelyEvaluatedForImpairmentMaximum
Namespace Prefix:	cbu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Refers to Troubled debt restructurings number of loans.

+ References

No definition available.

+ Details

Name:	cbu_TroubledDebtRestructurings
Namespace Prefix:	cbu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Refers to Troubled debt restructurings, accrual, number of loans.

+ References

No definition available.

+ Details

Name:	cbu_TroubledDebtRestructuringsAccruing
Namespace Prefix:	cbu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Refers to Troubled debt restructurings, accruing carrying balance.

+ References

No definition available.

+ Details

Name:	cbu_TroubledDebtRestructuringsAccruingCarryingBalance
Namespace Prefix:	cbu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Refers to Troubled debt restructurings, Nonaccrual, number of loans.

+ References

No definition available.

+ Details

Name:	cbu_TroubledDebtRestructuringsNonaccrual
Namespace Prefix:	cbu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Refers to Troubled debt restructurings, Nonaccrual carrying balance.

+ References

No definition available.

+ Details

Name:	cbu_TroubledDebtRestructuringsNonaccrualAmount
Namespace Prefix:	cbu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (h)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

+ Details

Name:	us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbu_ConsumerInstallmentDirectMember
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_HomeEquityReceivablesMember
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: