Name:	cban_EmployeeBenefitPlanElectiveEmployeeDeferredContributionsMinimumServicePeriod
Namespace Prefix:	cban_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the minimum age criteria for the eligibility of employer matching contribution under (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanEmployerMatchingContributionMinimumAge
Namespace Prefix:	cban_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the minimum service period of participant for the eligibility of employer matching contribution under (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanEmployerMatchingContributionMinimumServicePeriod
Namespace Prefix:	cban_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Employer matching contribution as a percentage of participant compensation under (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanEmployerMatchingContributionPercentageOnParticipantContribution
Namespace Prefix:	cban_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	cban_EmployeeBenefitPlanEmployerNonElectiveContributionAmount
Namespace Prefix:	cban_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the minimum age criteria for the eligibility of for non-elective plan contribution under (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanNonElectiveContributionMinimumAge
Namespace Prefix:	cban_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the minimum service hours for the eligibility of for non-elective plan contribution under (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanNonElectiveContributionMinimumHoursOfService
Namespace Prefix:	cban_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the minimum service period for the eligibility of for non-elective plan contribution under (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanNonElectiveContributionMinimumServicePeriod
Namespace Prefix:	cban_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Percentage of increase of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanParticipantContributionAutomaticIncreaseInDeferralRate
Namespace Prefix:	cban_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Maximum percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	cban_EmployeeBenefitPlanParticipantContributionAutomaticMaximumDeferralRate
Namespace Prefix:	cban_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Indicates (true false) whether description of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) is published and made available.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionAvailable
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionParticipantCompensationMatchedPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Name:	dei_LegalEntityAxis=cban_EBP002Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_StatementScenarioAxis=cban_FirstPortionOfSalaryDeductionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: