Name:	cbc_AgeOfLoansIdentifiedWithLossElement
Namespace Prefix:	cbc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

Refers to the period that loans are past due and classified as nonaccrual.

No definition available.

Name:	cbc_AgeOfLoansPlacedIntoNonaccrualStatus
Namespace Prefix:	cbc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

Loss recognized during the period that results from the write-down of loans receivables.

No definition available.

Name:	cbc_AmountOfImpairment
Namespace Prefix:	cbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Refers to expiration period of debt obligation.

No definition available.

Name:	cbc_ExpirationPeriodOfDebtObligations
Namespace Prefix:	cbc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

The maximum balance of financing receivables that were individually evaluated for impairment

No definition available.

Name:	cbc_LoansThatAreIndividualEvaluatedForImpairmentMaximum
Namespace Prefix:	cbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The minimum balance of financing receivables that were individually evaluated for impairment

No definition available.

Name:	cbc_LoansThatAreIndividuallyEvaluatedForImpairmentMinimum
Namespace Prefix:	cbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of days delinquent loans are charged off for closed-end loans.

No definition available.

Name:	cbc_NumberOfDaysDelinquentLoansAreChargedOffForClosed-EndLoans
Namespace Prefix:	cbc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

Number of days delinquent loans are charged off for revolving lines of credit.

No definition available.

Name:	cbc_NumberOfDaysDelinquentLoansAreChargedOffForRevolvingLinesOfCredit
Namespace Prefix:	cbc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

Refers to number of separate and consecutive statements.

No definition available.

Name:	cbc_NumberOfSeparateAndConsecutiveStatements
Namespace Prefix:	cbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Percentage of subsidiaries owned by parent company and required to file consolidated income tax return.

No definition available.

Name:	cbc_PercentageOfSubsidiariesOwnedByParentCompanyAndRequiredToFileConsolidatedFederalIncomeTaxReturn
Namespace Prefix:	cbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

This item refer to the period of federal funds transactions.

No definition available.

Name:	cbc_PeriodOfFederalFundsTransactions
Namespace Prefix:	cbc_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

Maximum award vesting period used to recognize compensation expense.

No definition available.

Name:	cbc_RestrictedCommonStockAwardVestingPeriodMaximum
Namespace Prefix:	cbc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Minimum award vesting period used to recognize compensation expense.

No definition available.

Name:	cbc_RestrictedCommonStockAwardVestingPeriodMinimum
Namespace Prefix:	cbc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The total assets of banking subsidiaries with loans individually evaluated.

No definition available.

Name:	cbc_TotalAssetsOfBankingSubsidiariesWithLoansIndividuallyEvaluated
Namespace Prefix:	cbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableGrossAllowanceAndNetAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_CashAndCashEquivalentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Unearned discounts (other than cash or quantity discounts and the like), finance charges, and interest included in the face amount of receivables, that are shown as a deduction from the related receivables. For example, 1) finance charges booked as a receivable when a loan is made and recognized as income at a later date; and 2) interest charges deducted from the face loan amount, resulting in a discounted amount actually advanced to the borrower (wherein the receivable includes the amount actually advanced to the borrower and the as yet unearned interest income).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6375948&loc=d3e4519-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Section A

-Paragraph 10

-Chapter 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_DeferredDiscountsFinanceChargesAndInterestIncludedInReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Name:	us-gaap_IncomeTaxDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_InterestAndFeeIncomeLoansAndLeasesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration