Consolidated Statements of Changes In Shareholders' Equity (Unaudited) (Parentheticals) - shares	3 Months Ended	6 Months Ended
Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Dividend reinvestment plan and restricted award forfeited and expired (in shares)	27	231	275

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