Condensed Consolidated Statements of Changes In Shareholders' Equity (Unaudited) (Parentheticals) - shares shares in Thousands	9 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Shares associated with stock awards (in shares)	4,201	6,321
Dividend reinvestment plan and restricted award forfeited and expired (in shares)		204

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