Securities (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Securities Income Tax Provision On Net Realized Gain Loss	$ 1	$ 1	$ 39	$ 12

This item represents the tax provision applicable to net realized gain or loss.

No definition available.

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