Financing receivable modifications percentage of loans outstanding.

No definition available.

Name:	civb_FinancingReceivableModificationsPercentageOfLoansOutstanding
Namespace Prefix:	civb_
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_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable modified as troubled debt restructuring.

+ 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 http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554

+ Details

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

- Details

Name:	us-gaap_LoanRestructuringModificationNameAxis=civb_SecondModificationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_CommercialAndAgricultureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_CommercialRealEstateNonOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Allowance for Loan Losses - Schedule of Loan Modifications (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2020 Contract	Dec. 31, 2021 USD ($) Contract	Dec. 31, 2019 Contract	Dec. 31, 2020 USD ($)
Financing Receivable Modifications [Line Items]
Number of loans modified			1
Loans modified as troubled debt restructuring \| $		$ 0		$ 0
Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified		7
Loans modified as troubled debt restructuring \| $		$ 5,142
Percent of Loans Outstanding		0.26%
Commercial and Agriculture [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified	813
Loans modified as troubled debt restructuring \| $				$ 431,300
Commercial and Agriculture [Member] \| Second Modifications [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified		7
Loans modified as troubled debt restructuring \| $		$ 5,142
Commercial and Agriculture [Member] \| Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified		2
Loans modified as troubled debt restructuring \| $		$ 498
Percent of Loans Outstanding		0.03%
Commercial Real Estate Non Owner Occupied [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified			1
Commercial Real Estate Non Owner Occupied [Member] \| Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified		5
Loans modified as troubled debt restructuring \| $		$ 4,644
Percent of Loans Outstanding		0.24%