Name:	cbkm_FederalHomeLoanBankAdvancesPrincipalPaymentsInNextTwelveMonths
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Amount of principal payments towards federal home loan bank advances in the fourth fiscal year following the latest fiscal year.

No definition available.

Name:	cbkm_FederalHomeLoanBankAdvancesPrincipalPaymentsInYearFour
Namespace Prefix:	cbkm_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of principal payments towards federal home loan bank advances in the third fiscal year following the latest fiscal year.

No definition available.

Name:	cbkm_FederalHomeLoanBankAdvancesPrincipalPaymentsInYearThree
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of principal payments towards federal home loan bank advances in the second fiscal year following the latest fiscal year.

No definition available.

Name:	cbkm_FederalHomeLoanBankAdvancesPrincipalPaymentsInYearTwo
Namespace Prefix:	cbkm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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.

No definition available.

Name:	us-gaap_FederalHomeLoanBankAdvancesLineItems
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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64702-112823

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822