Loans (Details Textual) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Mar. 31, 2015	Jun. 30, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment in loans:	$ 517cbkm_RecordedInvestmentInLoans	$ 491cbkm_RecordedInvestmentInLoans
Loans and Leases Receivable, Deferred Income	412cbkm_DeferredLoanFees	388cbkm_DeferredLoanFees
Financing Receivable, Recorded Investment, Equal To Greater Than 90 Days Past Due	531	1,706
Financing Receivable, Recorded Investment, 30 To 59 Days Past Due	327	283
Financing Receivable, Recorded Investment, 60 To 89 Days Past Due	72	161
Financing Receivable, Recorded Investment, Nonaccrual Status	628	1,959
Financing Receivable, Modifications, Recorded Investment	1,497	1,528
Troubled Debt Restructuring, Debtor, Subsequent Periods, Contingent Payments, Amount	92	118
Total Outstanding On Commercial and Commercial Real Estate Loans	100
Non-accrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Equal To Greater Than 90 Days Past Due	511	1,706
Financing Receivable, Recorded Investment, 30 To 59 Days Past Due	9	40
Financing Receivable, Recorded Investment, 60 To 89 Days Past Due		122
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 108	$ 91

Expenses incurred on deferred loans.

No definition available.

Name:	cbkm_DeferredLoanFees
Namespace Prefix:	cbkm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount included in the recorded investment in loans.

+ References

No definition available.

+ Details

Name:	cbkm_RecordedInvestmentInLoans
Namespace Prefix:	cbkm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total amount outstanding on commercial and commercial real estate loan relationship greater than non-homogeneous loans.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

+ Details

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

- Definition

Financing receivables that are less than 60 days past due but more than 29 days past due.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment30To59DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing receivables that are less than 90 days past due but more than 59 days past due.

+ References

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment60To89DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing receivables that are equal to or greater than 90 days past due.

+ References

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5111-111524

+ Details

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

- Definition

Amount of restructured debt contingently payable based on the occurrence of future events or circumstances.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 60

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6402221&loc=d3e15765-112638

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: