XML 42 R32.htm IDEA: XBRL DOCUMENT
v3.21.2

Summary of Significant Accounting Policies (Details) | 6 Months Ended
--- | ---
Jun. 30, 2021
Accounting Policies [Abstract] |
Percentage of loan portfolio concentrated in loans secured by real estate | 82.00%

X
- Definition Percentage of loan portfolio concentrated in loans secured by real estate. + References No definition available. + Details
Name: | cban_PercentageOfLoanPortfolioConcentratedInLoansSecuredByRealEstate
Namespace Prefix: | cban_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration