Represents the average balance of a specified grouping or category of loans receivable as of the specified date.

No definition available.

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

- Definition

Represents the credit fair value adjustment on credit impaired loans at the acquisition date.

+ References

No definition available.

+ Details

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- Definition

Represents the credit fair value adjustment on non-credit impaired loans at the acquisition date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of loans receivable acquired at the acquisition date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Represents the market rate adjustment on loans receivable at the acquisition date.

+ References

No definition available.

+ Details

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Namespace Prefix:	cznc_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The amount of loans and leases receivable with balances greater than $500,000.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The percent of total loans of loans with balances greater than $500,000.

+ References

No definition available.

+ Details

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Namespace Prefix:	cznc_
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Balance Type:	na
Period Type:	instant

- Definition

The amount of liquidation shortfall for loans and leases receivable.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The liquidation value of loans and leases receivable.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the number of borrowers of loans of $500,000 or more as of the specified date.

+ References

No definition available.

+ Details

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Namespace Prefix:	cznc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of loans of $500,000 or more as of the specified date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Represents the loans receivable balance of loans of $500,000 or more.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the percentage of the loans receivable balance consisting of loans of $500,000 or more.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Represents the number of loans as of the specified date.

+ References

No definition available.

+ Details

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Namespace Prefix:	cznc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of loans classified as special mention.

+ References

No definition available.

+ Details

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Namespace Prefix:	cznc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects the amount of the write-down related to a troubled debt restructuring.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
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-Paragraph 4
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring.

+ References

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-Name Accounting Standards Codification
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Balance Type:	debit
Period Type:	instant

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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Balance Type:
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Note 8 - Loans (Details Textual)	12 Months Ended
Note 8 - Loans (Details Textual)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Apr. 01, 2019 USD ($)	Dec. 31, 2017 USD ($)
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums, Total	$ 2,482,000	$ 1,999,000
Loans and Leases Receivable, Gross, Total	$ 1,182,222,000	827,563,000
Number of Special Mention Loans	60
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 1,051,000	1,605,000
Financing Receivable, Allowance for Credit Loss, Ending Balance	9,836,000	9,309,000		$ 8,856,000
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	0	0
Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	$ 0
Loans Upgraded from Substandard to Special Mention in Following Fiscal Year [Member]
Number of Loans		2
Financing Receivable, Allowance for Credit Loss, Ending Balance		$ 1,365,000
Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Gross, Total	578,901,000	353,627,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	875,000	1,489,000
Financing Receivable, Allowance for Credit Loss, Ending Balance	4,788,000	4,591,000		4,235,000
Commercial Portfolio Segment [Member] \| Largest Loan Balance [Member]
Loans and Leases Receivable, Gross, Total	$ 1,261,000
Number of Loans	1
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 678,000
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable, Gross, Total	33,555,000	11,962,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	678,000	0
Financing Receivable, Allowance for Credit Loss, Ending Balance	966,000	110,000		$ 150,000
Special Mention [Member]
Loans and Leases Receivable, Gross, Total	19,658,000	7,394,000
Average Balance of Loans Receivable	328,000	$ 140,000
Number of Loans		53
Loans Receivable, Balance of Loans of $500,000 or More	$ 15,357,000
Loans Receivable Balance, Percentage of Loans of $500,000 or More	78.00%
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 0	$ 0
Loans and Leases Receivable, Balances Greater Than $500,000	15,357,000	11,922,000
Special Mention [Member] \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Gross, Total	$ 19,327,000	6,222,000
Loans of $500,000 or More, Number of Loans	9
Loans of $500,000 or More, Number of Borrowers	7
Special Mention [Member] \| Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable, Gross, Total	$ 0	0
Substandard [Member]
Loans and Leases Receivable, Gross, Total	18,504,000	19,556,000
Average Balance of Loans Receivable	$ 82,000	$ 91,000
Number of Loans	225	215
Loans and Leases Receivable, Balances Greater Than $500,000	$ 4,185,000
Loans and Leases Receivable, Balances Greater Than $500,000, Percent of Loans	23.00%
Substandard [Member] \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Gross, Total	$ 8,279,000	$ 10,564,000
Substandard [Member] \| Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable, Gross, Total	1,331,000	75,000
Financial Asset Acquired with Credit Deterioration [Member]
Loans and Leases Receivable, Gross, Total	441,000
Financial Asset Acquired with Credit Deterioration [Member] \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Gross, Total	364,000
Financial Asset Acquired with Credit Deterioration [Member] \| Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable, Gross, Total	0
Financial Asset Originated [Member]
Loans and Leases Receivable, Gross, Total	$ 4,135,000	$ 0
Number of Loans	2
Financial Asset Originated [Member] \| Special Mention [Member]
Loans and Leases Receivable, Gross, Total	$ 3,500,000
Loans and Leases Receivable, Liquidation Value	1,500,000
Loans and Leases Receivable, Liquidation Shortfall	$ 2,000,000
Loans Receivable 1 [Member] \| Credit Availability Concentration Risk [Member]
Concentration Risk, Percentage	0.00%
Monument Bancorp, Inc [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable			$ 259,295,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable, Market Rate Adjustment			(1,807,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Credit Fair Value Adjustment on Non-credit Impaired Loans			(1,914,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Credit Fair Value Adjustment on Impaired Loans			(318,000)
Monument Bancorp, Inc [Member] \| Commercial Portfolio Segment [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable			144,968,000
Monument Bancorp, Inc [Member] \| Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable			4,617,000
Monument Bancorp, Inc [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable			441,000
Monument Bancorp, Inc [Member] \| Financial Asset Acquired with Credit Deterioration [Member] \| Commercial Portfolio Segment [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable			364,000
Monument Bancorp, Inc [Member] \| Financial Asset Acquired with Credit Deterioration [Member] \| Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable			$ 0