Condensed Consolidated Statements of Changes In Stockholders' Equity (Unaudited) (Parentheticals) - shares shares in Thousands	3 Months Ended
Sep. 30, 2016	Sep. 30, 2015
Dividend Reinvestment Plan and Restricted Award Forfeited and Expired (in shares)	231	248

The number of dividend reinvestment plan shares associated with forfeited restricted stock awards retired to treasury.

No definition available.

Name:	cbkm_StockIssuedDuringPeriodSharesDividendReinvestmentPlanAndRestrictedAwardForfeitedAndExpired
Namespace Prefix:	cbkm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration