Loans, Troubled Debt Restructurings Segregated by Class (Details) (USD $)	12 Months Ended
Dec. 31, 2014 Loan	Dec. 31, 2013 Loan
Financing Receivable, Modifications [Line Items]
Number of Loans	22	64
Post-Modification Outstanding Balance	$ 7,898,000	$ 15,087,000
Commitment to extend additional credit on loans modified	100,000
Past due period for loan to be considered in default, minimum	90 days
Defaulted Restructured Loans, Number of Loans	2	9
Defaulted Restructured Loans, Recorded Balance	669,000	1,058,000
Term Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	6,982,000	12,015,000
Rate Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	0
Combination [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	916,000	3,072,000
Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	6
Post-Modification Outstanding Balance	7,000	2,603,000
Commercial Construction [Member] \| Term Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	7,000	2,603,000
Commercial Construction [Member] \| Rate Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	0
Commercial Construction [Member] \| Combination [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	0
Commercial Secured by Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	11	27
Post-Modification Outstanding Balance	5,775,000	5,488,000
Defaulted Restructured Loans, Number of Loans		2
Defaulted Restructured Loans, Recorded Balance		89,000
Commercial Secured by Real Estate [Member] \| Term Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	5,707,000	2,568,000
Commercial Secured by Real Estate [Member] \| Rate Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	0
Commercial Secured by Real Estate [Member] \| Combination [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	68,000	2,920,000
Commercial Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	8	30
Post-Modification Outstanding Balance	1,268,000	6,623,000
Defaulted Restructured Loans, Number of Loans	1	6
Defaulted Restructured Loans, Recorded Balance	88,000	596,000
Commercial Other [Member] \| Term Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	1,268,000	6,471,000
Commercial Other [Member] \| Rate Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	0
Commercial Other [Member] \| Combination [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	152,000
Real Estate Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2	1
Post-Modification Outstanding Balance	848,000	373,000
Defaulted Restructured Loans, Number of Loans	1	1
Defaulted Restructured Loans, Recorded Balance	581,000	373,000
Real Estate Mortgage [Member] \| Term Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	373,000
Real Estate Mortgage [Member] \| Rate Modification [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	0	0
Real Estate Mortgage [Member] \| Combination [Member]
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Balance	$ 848,000	$ 0

Refers to the commitments to extend additional credit on loans that are considered troubled debt restructurings.

No definition available.

Name:	ctbi_FinancingReceivableModificationsCommitmentToExtendAdditionalCreditOnLoansModified
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Refers to the minimum past due period for a loan to be considered in default.

+ References

No definition available.

+ Details

Name:	ctbi_PastDuePeriodForLoanToBeConsideredInDefaultMinimum
Namespace Prefix:	ctbi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ctbi_LoanRestructuringModificationAxis=ctbi_ContractualInterestRateReductionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ctbi_LoanRestructuringModificationAxis=ctbi_ExtendedMaturityAndRateReductionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ctbi_LoanRestructuringModificationAxis=ctbi_ExtendedMaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=ctbi_CommercialOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_CommercialRealEstateOtherReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_MortgageLoansOnRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: