FAIR VALUE MEASUREMENTS AND FAIR VALUES OF FINANCIAL INSTRUMENTS - Level 3 Valuation Techniques Nonrecurring (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1	$ 3,460	$ 6,540
Impaired Financing Receivable, Related Allowance1	453	740
Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1	3,007	5,800
Foreclosed assets held for sale	275	684
Residential mortgage
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	0	256
Commercial \| Real estate loan
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1	3,400	6,468
Impaired Financing Receivable, Related Allowance1	427	668
Commercial \| Commercial and industrial
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1	60	72
Impaired Financing Receivable, Related Allowance1	26	72
Impaired Loans
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1	3,460
Impaired Financing Receivable, Related Allowance1	453
Fair value	3,007
Impaired Loans \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale		6,540
Valuation allowance		740
Fair value		5,800
Impaired Loans \| Valuation, Market Approach \| Commercial \| Real estate loan
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1		428
Impaired Financing Receivable, Related Allowance1		0
Fair value		428
Impaired Loans \| Valuation, Market Approach \| Commercial \| Real estate loan \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1	3,400	6,468
Impaired Financing Receivable, Related Allowance1	427	668
Fair value	$ 2,973	$ 5,800
Impaired Loans \| Valuation, Market Approach \| Commercial \| Real estate loan \| Weighted average
Valuation Techniques and the Unobservable Inputs
Discount rate		50.00%
Impaired Loans \| Valuation, Market Approach \| Commercial \| Real estate loan \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	25.00%	27.00%
Impaired Loans \| Valuation, Market Approach \| Commercial \| Commercial and industrial \| Measurement Input Discount To Borrowers Financial Statement Value Member
Valuation Techniques and the Unobservable Inputs
Impaired Financing Receivable, with Related Allowance, Recorded Investment1		$ 72
Impaired Financing Receivable, Related Allowance1		72
Fair value		$ 0
Impaired Loans \| Valuation, Market Approach \| Commercial \| Commercial and industrial \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	$ 60
Valuation allowance	26
Fair value	$ 34
Impaired Loans \| Valuation, Market Approach \| Commercial \| Commercial and industrial \| Weighted average \| Measurement Input Discount To Borrowers Financial Statement Value Member
Valuation Techniques and the Unobservable Inputs
Discount rate		100.00%
Impaired Loans \| Valuation, Market Approach \| Commercial \| Commercial and industrial \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	33.00%
Foreclosed Assets Held For Sale
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	$ 275
Valuation allowance	0
Fair value	275
Foreclosed Assets Held For Sale \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale		$ 684
Valuation allowance		0
Fair value		684
Foreclosed Assets Held For Sale \| Valuation, Market Approach \| Commercial Real Estate Receivables \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	275	256
Valuation allowance	0	0
Fair value	$ 275	$ 256
Foreclosed Assets Held For Sale \| Valuation, Market Approach \| Commercial Real Estate Receivables \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	50.00%	53.00%

The fair value of foreclosed real estate.

No definition available.

Name:	cznc_ForeclosedRealEstateFairValue
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 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

The fair value of impaired loans.

+ References

No definition available.

+ Details

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

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

No definition available.

+ Details

Name:	cznc_ModelingPeriodRate
Namespace Prefix:	cznc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11
-URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5162-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124259787&loc=d3e4437-111522

+ Details

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

- Definition

For each period for which an income statement is required, disclosure of the changes in the allowance, including balances at end of period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

+ Details

Name:	us-gaap_RealEstateOwnedValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
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_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_FairValueByAssetClassAxis=cznc_ImpairedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MeasurementInputTypeAxis=cznc_MeasurementInputDiscountToBorrowersFinancialStatementValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=cznc_ForeclosedAssetsHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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