XML 70 R60.htm IDEA: XBRL DOCUMENT
v3.21.2

Fair Value of Financial Instruments and Fair Value Measurements - Narrative (Details) | Sep. 30, 2021
--- | ---
Fair Value Disclosures [Abstract] |
Fair value input, discount amount | 10.00%

X
- Definition Refers to the discounted rate to account for selling and marketing costs in fair value measurements. + References No definition available. + Details
Name: | cban_DiscountedRateToAccountForSellingAndMarketingCosts
Namespace Prefix: | cban_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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