Loans held for investment - Changes in Troubled Debt Restructurings (Detail) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2022 USD ($) Loan	Dec. 31, 2021 USD ($) Loan
Financing Receivable, Modifications [Line Items]
Number of Loans \| Loan	1	3
Principal paydowns, Recorded Investment	$ (73)	$ (112)
Additional loans with concessions, Recorded Investment		213
Post-Modification Outstanding Recorded Investment	$ 140	$ 2,113
OREO [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| Loan		2
Debt Restructuring Reclassifications		$ (1,788)

Debt restructuring reclassifications.

No definition available.

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Period Type:	duration

- Definition

Financing Receivable, Modifications, Collections During Period

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Financing Receivable, Modifications, Recorded Investment During Period

+ References

No definition available.

+ Details

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Namespace Prefix:	cizn_
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Period Type:	duration

- 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

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Namespace Prefix:	us-gaap_
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

+ Details

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- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

+ Details

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- Details

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