Financing receivable acquired with credit deterioration.

No definition available.

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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

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 http://asc.fasb.org/extlink&oid=119407570&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 http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=119407570&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 http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446

+ Details

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

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-Section 50
-Paragraph 13
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-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

+ 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

+ 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

+ Details

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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

+ 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=118952595&loc=d3e4428-111522

+ Details

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

- Details

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- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=civb_RealEstateConstructionMember
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- Details

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- Details

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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, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	$ 104		$ 141
Allowance for loan losses, Collectively evaluated for impairment	14,040		13,530
Allowance for loan losses, Total	14,144	$ 13,786	13,679	$ 13,331	$ 12,867	$ 13,134
Outstanding loan balances, Individually evaluated for impairment	2,899		2,857
Outstanding loan balances, Collectively evaluated for impairment	1,645,202		1,558,160
Outstanding loan balances, Total	1,648,640		1,561,941
Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with credit deterioration			8
Loan balance of loans acquired with credit deterioration	539		924
Commercial and Agriculture [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	1,932		1,747
Allowance for loan losses, Total	1,932	1,828	1,747	1,631	1,630	1,562
Outstanding loan balances, Individually evaluated for impairment	367		367
Outstanding loan balances, Collectively evaluated for impairment	196,466		176,693
Outstanding loan balances, Total	196,833		177,101
Commercial and Agriculture [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan balance of loans acquired with credit deterioration			41
Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	6		12
Allowance for loan losses, Collectively evaluated for impairment	2,131		1,950
Allowance for loan losses, Total	2,137	2,009	1,962	2,043	2,161	2,043
Outstanding loan balances, Individually evaluated for impairment	436		484
Outstanding loan balances, Collectively evaluated for impairment	226,065		209,637
Outstanding loan balances, Total	226,501		210,121
Commercial Real Estate Non Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	6,148		5,803
Allowance for loan losses, Total	6,148	5,867	5,803	5,445	5,135	5,307
Outstanding loan balances, Individually evaluated for impairment	376		31
Outstanding loan balances, Collectively evaluated for impairment	558,428		523,567
Outstanding loan balances, Total	558,804		523,598
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment	98		122
Allowance for loan losses, Collectively evaluated for impairment	1,511		1,401
Allowance for loan losses, Total	1,609	1,698	1,531	1,799	1,691	1,910
Outstanding loan balances, Individually evaluated for impairment	1,039		1,279
Outstanding loan balances, Collectively evaluated for impairment	463,877		455,688
Outstanding loan balances, Total	465,455		457,850
Residential Real Estate [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with credit deterioration			8
Loan balance of loans acquired with credit deterioration	539		883
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	1,183		1,046
Allowance for loan losses, Total	1,183	1,135	1,046	981	861	834
Outstanding loan balances, Collectively evaluated for impairment	149,018		135,195
Outstanding loan balances, Total	149,018		135,195
Farm Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Individually evaluated for impairment			7
Allowance for loan losses, Collectively evaluated for impairment	367		390
Allowance for loan losses, Total	367	365	397	393	410	430
Outstanding loan balances, Individually evaluated for impairment	681		696
Outstanding loan balances, Collectively evaluated for impairment	35,605		37,817
Outstanding loan balances, Total	36,286		38,513
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	253		284
Allowance for loan losses, Total	253	201	284	315	300	290
Outstanding loan balances, Collectively evaluated for impairment	15,743		19,563
Outstanding loan balances, Total	15,743		19,563
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Collectively evaluated for impairment	515		909
Allowance for loan losses, Total	$ 515	$ 683	$ 909	$ 724	$ 679	$ 758