Financing receivable acquired with credit deterioration.

No definition available.

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Namespace Prefix:	civb_
Data Type:	xbrli:monetaryItemType
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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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- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	credit
Period Type:	instant

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ 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 (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

+ Details

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Namespace Prefix:	us-gaap_
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 http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

+ Details

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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

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 http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

+ 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 http://asc.fasb.org/extlink&oid=84173941&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 http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

+ Details

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Namespace Prefix:	us-gaap_
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 http://asc.fasb.org/extlink&oid=82891408&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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Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_CommercialRealEstateNonOwnerOccupiedMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
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Data Type:	na
Balance Type:
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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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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_ConsumerAndOtherMember
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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, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	$ 366		$ 125
Allowance for loan losses, Collectively evaluated for impairment	12,935		12,883
Allowance for loan losses, Total	13,331	$ 12,867	13,134	$ 12,946	$ 13,047	$ 13,305
Outstanding loan balances, Individually evaluated for impairment	3,953		3,460
Outstanding loan balances, Collectively evaluated for impairment	1,510,676		1,160,986
Outstanding loan balances, Total	1,515,644		1,164,661
Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with credit deterioration	30		126
Loan balance of loans acquired with credit deterioration	1,015		215
Commercial and Agriculture [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment			4
Allowance for loan losses, Collectively evaluated for impairment	1,631		1,476
Allowance for loan losses, Total	1,631	1,630	1,562	1,611	1,608	2,018
Outstanding loan balances, Individually evaluated for impairment	390		438
Outstanding loan balances, Collectively evaluated for impairment	169,249		151,948
Outstanding loan balances, Total	169,686		152,473
Commercial and Agriculture [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with credit deterioration			82
Loan balance of loans acquired with credit deterioration	47		87
Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	10		6
Allowance for loan losses, Collectively evaluated for impairment	2,033		2,037
Allowance for loan losses, Total	2,043	2,161	2,043	2,073	2,010	2,171
Outstanding loan balances, Individually evaluated for impairment	505		1,010
Outstanding loan balances, Collectively evaluated for impairment	202,582		163,089
Outstanding loan balances, Total	203,087		164,099
Commercial Real Estate Non Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	5,445		5,307
Allowance for loan losses, Total	5,445	5,135	5,307	5,273	4,739	4,606
Outstanding loan balances, Individually evaluated for impairment	36		44
Outstanding loan balances, Collectively evaluated for impairment	499,204		425,579
Outstanding loan balances, Total	499,240		425,623
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	350		109
Allowance for loan losses, Collectively evaluated for impairment	1,419		1,757
Allowance for loan losses, Total	1,799	1,691	1,910	2,479	2,676	3,089
Outstanding loan balances, Individually evaluated for impairment	2,315		1,360
Outstanding loan balances, Collectively evaluated for impairment	455,738		267,247
Outstanding loan balances, Total	459,021		268,735
Residential Real Estate [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with credit deterioration	30		44
Loan balance of loans acquired with credit deterioration	968		128
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	981		834
Allowance for loan losses, Total	981	861	834	667	482	420
Outstanding loan balances, Collectively evaluated for impairment	126,288		97,531
Outstanding loan balances, Total	126,288		97,531
Farm Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	6		6
Allowance for loan losses, Collectively evaluated for impairment	387		424
Allowance for loan losses, Total	393	410	430	424	425	442
Outstanding loan balances, Individually evaluated for impairment	707		608
Outstanding loan balances, Collectively evaluated for impairment	37,331		38,853
Outstanding loan balances, Total	38,038		39,461
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	315		290
Allowance for loan losses, Total	315	300	290	325	324	314
Outstanding loan balances, Collectively evaluated for impairment	20,284		16,739
Outstanding loan balances, Total	20,284		16,739
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	724		758
Allowance for loan losses, Total	$ 724	$ 679	$ 758	$ 94	$ 783	$ 245