Financing receivable acquired with credit deterioration.

No definition available.

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Namespace Prefix:	civb_
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

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Period Type:	duration

- Definition

Amount of allowance for credit loss on accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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

- 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

+ Details

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

- Details

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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_CommercialAndAgricultureMember
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Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_CommercialRealEstateOwnerOccupiedMember
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Balance Type:
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_CommercialRealEstateNonOwnerOccupiedMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_RealEstateConstructionMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_FarmRealEstateMember
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Data Type:	na
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_ConsumerAndOtherMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
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Allowance for Loan Losses - Ending Allocation of Allowance for Loan Losses and Loan Balances Outstanding (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	$ 7		$ 18
Allowance for loan losses, Collectively evaluated for impairment	27,766		26,623
Allowance for loan losses, Total	27,773	$ 27,435	26,641	$ 26,568	$ 26,197	$ 25,028
Outstanding loan balances, Individually evaluated for impairment	1,902		1,222
Outstanding loan balances, Collectively evaluated for impairment	2,322,602		1,996,367
Outstanding loan balances, Total	2,328,614		1,997,879
Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts Notes And Loans Receivable [Line Items]
Loan balance of loans acquired with credit deterioration	4,110		290
Commercial and Agriculture [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	2,729		2,600
Allowance for loan losses, Total	2,729	2,790	2,600	2,512	2,320	2,810
Outstanding loan balances, Individually evaluated for impairment	343
Outstanding loan balances, Collectively evaluated for impairment	226,235		246,502
Outstanding loan balances, Total	227,387		246,502
Commercial and Agriculture [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts Notes And Loans Receivable [Line Items]
Loan balance of loans acquired with credit deterioration	809
Commercial Real Estate Owner Occupied [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	6		7
Allowance for loan losses, Collectively evaluated for impairment	4,920		4,457
Allowance for loan losses, Total	4,926	4,729	4,464	4,416	4,027	4,057
Outstanding loan balances, Individually evaluated for impairment	833		187
Outstanding loan balances, Collectively evaluated for impairment	361,865		295,265
Outstanding loan balances, Total	364,468		295,452
Commercial Real Estate Owner Occupied [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts Notes And Loans Receivable [Line Items]
Loan balance of loans acquired with credit deterioration	1,770
Commercial Real Estate Non Owner Occupied [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	14,427		13,860
Allowance for loan losses, Total	14,427	14,711	13,860	13,170	13,546	12,451
Outstanding loan balances, Individually evaluated for impairment	140		0
Outstanding loan balances, Collectively evaluated for impairment	955,909		829,310
Outstanding loan balances, Total	956,169		829,310
Commercial Real Estate Non Owner Occupied [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts Notes And Loans Receivable [Line Items]
Loan balance of loans acquired with credit deterioration	120
Residential Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	1		11
Allowance for loan losses, Collectively evaluated for impairment	3,035		2,586
Allowance for loan losses, Total	3,036	2,859	2,597	2,596	2,531	2,484
Outstanding loan balances, Individually evaluated for impairment	586		526
Outstanding loan balances, Collectively evaluated for impairment	529,168		429,244
Outstanding loan balances, Total	531,164		430,060
Residential Real Estate [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts Notes And Loans Receivable [Line Items]
Loan balance of loans acquired with credit deterioration	1,410		290
Real Estate Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	2,013		1,810
Allowance for loan losses, Total	2,013	1,969	1,810	2,459	2,177	2,439
Outstanding loan balances, Collectively evaluated for impairment	202,793		157,127
Outstanding loan balances, Total	202,793		157,127
Farm Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	251		287
Allowance for loan losses, Total	251	236	287	308	290	338
Outstanding loan balances, Individually evaluated for impairment			509
Outstanding loan balances, Collectively evaluated for impairment	25,636		27,910
Outstanding loan balances, Total	25,636		28,419
Consumer and Other [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	142		176
Allowance for loan losses, Total	142	130	176	212	202	209
Outstanding loan balances, Collectively evaluated for impairment	20,996		11,009
Outstanding loan balances, Total	20,997		11,009
Consumer and Other [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts Notes And Loans Receivable [Line Items]
Loan balance of loans acquired with credit deterioration	1
Unallocated [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	249		847
Allowance for loan losses, Total	$ 249	$ 11	$ 847	$ 895	$ 1,104	$ 240