Securities (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Securities Income Tax Provision On Gross Realized Gains	$ 29		$ 42
Available For Sale Securities Income Tax Provision On Net Realized Gain Loss		$ 11		$ 11

This item represents the tax provision applicable to gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

No definition available.

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