FAIR VALUE MEASUREMENTS AND FAIR VALUES OF FINANCIAL INSTRUMENTS - Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Reported value measurement \| Level 1
Fair values, and carrying amounts financial instruments not recorded at fair value
Cash and cash equivalents	$ 42,348	$ 52,778
Reported value measurement \| Level 2
Fair values, and carrying amounts financial instruments not recorded at fair value
Certificates of deposit	4,100	4,100
Restricted equity securities (included in Other Assets)	22,782	21,716
Accrued interest receivable	9,465	9,140
Short-term borrowings	48,831	33,874
Long-term borrowings	148,824	138,337
Senior debt	14,848	14,831
Subordinated debt	24,745	24,717
Accrued interest payable	2,124	1,525
Reported value measurement \| Level 2 \| Deposits with no stated maturity
Fair values, and carrying amounts financial instruments not recorded at fair value
Deposits, fair value	1,563,605	1,590,357
Reported value measurement \| Level 2 \| Time deposits
Fair values, and carrying amounts financial instruments not recorded at fair value
Deposits, fair value	432,298	424,449
Reported value measurement \| Level 3
Fair values, and carrying amounts financial instruments not recorded at fair value
Loans, net	1,852,426	1,828,931
Estimate of fair value measurement \| Level 1
Fair values, and carrying amounts financial instruments not recorded at fair value
Cash and cash equivalents	42,348	52,778
Estimate of fair value measurement \| Level 2
Fair values, and carrying amounts financial instruments not recorded at fair value
Certificates of deposit	3,896	3,859
Restricted equity securities (included in Other Assets)	22,782	21,716
Accrued interest receivable	9,465	9,140
Short-term borrowings	48,831	33,874
Long-term borrowings	148,009	137,775
Senior debt	13,455	12,706
Subordinated debt	22,373	22,750
Accrued interest payable	2,124	1,525
Estimate of fair value measurement \| Level 2 \| Deposits with no stated maturity
Fair values, and carrying amounts financial instruments not recorded at fair value
Deposits, fair value	1,563,605	1,590,357
Estimate of fair value measurement \| Level 2 \| Time deposits
Fair values, and carrying amounts financial instruments not recorded at fair value
Deposits, fair value	430,309	423,643
Estimate of fair value measurement \| Level 3
Fair values, and carrying amounts financial instruments not recorded at fair value
Loans, net	$ 1,766,292	$ 1,750,336

Represents the fair value portion of accrued interest payable.

No definition available.

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Period Type:	instant

- Definition

The fair value of Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

+ References

No definition available.

+ Details

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

- Definition

The fair value disclosure of a savings certificate entitling the Entity (that is, bearer) to receive interest at an established maturity date, based upon a fixed interest rate. A certificate of deposit may be issued in any denomination. Certificates of deposit are generally issued by commercial banks and, therefore, insured by the FDIC (up to the prescribed limit). Certificates of deposit generally restrict holders from withdrawing funds on demand without the incurrence of penalties. Generally, only certificates of deposit with original maturities of three months or less qualify as cash equivalents. Original maturity means original maturity to the entity holding the investment. As a related example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

No definition available.

+ Details

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

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of subordinated debt existing as of the balance sheet date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

+ Details

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Balance Type:	credit
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2E

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Publisher FASB
-URI https://asc.fasb.org//310-10/tableOfContent

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	debit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of notes payable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20,22)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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Balance Type:	credit
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- Definition

The aggregate value of all restricted investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-12(Column C)(Footnote 8)(c))
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-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 954
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-Topic 954
-SubTopic 210
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480602/954-210-50-2

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

+ References

No definition available.

+ Details

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