LOANS AND ALLOWANCE FOR CREDIT LOSSES - Impaired Loans (Details) $ in Thousands	Dec. 31, 2022 USD ($)
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	$ 22,508
Recorded Investment - with no allowance	15,898
Related Allowance - with no allowance	0
Unpaid Principal Balance - with allowance	3,460
Recorded Investment - with allowance	3,460
Related Allowance - with allowance	453
Unpaid Principal Balance	25,968
Recorded Investment	19,358
Commercial \| Real estate loan
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	8,563
Recorded Investment - with no allowance	3,754
Related Allowance - with no allowance	0
Unpaid Principal Balance - with allowance	3,400
Recorded Investment - with allowance	3,400
Related Allowance - with allowance	427
Commercial \| Commercial and industrial
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	12,926
Recorded Investment - with no allowance	11,163
Related Allowance - with no allowance	0
Unpaid Principal Balance - with allowance	60
Recorded Investment - with allowance	60
Related Allowance - with allowance	26
Commercial \| Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	68
Recorded Investment - with no allowance	68
Related Allowance - with no allowance	0
Commercial \| Loans secured by farm land
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	76
Recorded Investment - with no allowance	76
Related Allowance - with no allowance	0
Commercial \| Multi-family (5 or more) residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	0
Recorded Investment - with no allowance	0
Related Allowance - with no allowance	0
Commercial \| Agricultural loans
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	57
Recorded Investment - with no allowance	57
Related Allowance - with no allowance	0
Commercial \| Construction And Other Land Loans
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	244
Recorded Investment - with no allowance	244
Related Allowance - with no allowance	0
Residential mortgage \| Real estate loan \| first liens
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	506
Recorded Investment - with no allowance	506
Related Allowance - with no allowance	0
Residential mortgage \| Real estate loan \| junior liens
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Unpaid Principal Balance - with no allowance	68
Recorded Investment - with no allowance	30
Related Allowance - with no allowance	$ 0

Amount of allowance for credit losses not related to recorded investment.

No definition available.

Name:	cznc_ImpairedFinancingReceivableNoRelatedAllowance
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableRecordedInvestment1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableRelatedAllowance1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableUnpaidPrincipalBalance1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	cznc_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance1
Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cznc_CommercialAndIndustrialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cznc_HomeEquityLineOfCredit1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cznc_LoansSecuredByFarmlandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cznc_Multifamily5OrMoreResidentialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cznc_AgriculturalLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cznc_ConstructionAndOtherLandLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LienCategoryAxis=us-gaap_SeniorLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LienCategoryAxis=us-gaap_JuniorLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: