Loans, Major Classifications of Loans, Net of Income and Deferred Loan Origination Cost (Details) $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($) Segment	Dec. 31, 2017 USD ($)
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	$ 3,208,638	$ 3,122,940
Number of portfolio segments \| Segment	9
Loans held for sale [Abstract]
Loans held for sale	$ 2,461	1,033
Commercial [Member] \| Construction [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	82,715	76,479
Commercial [Member] \| Real Estate [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	1,183,093	1,188,680
Commercial [Member] \| Equipment Lease Financing [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	1,740	3,042
Commercial [Member] \| Other [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	377,198	351,034
Residential [Member] \| Construction [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	57,160	67,358
Residential [Member] \| Real Estate [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	722,417	709,570
Residential [Member] \| Home Equity [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	106,299	99,356
Consumer [Member] \| Consumer Direct [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	144,289	137,754
Consumer [Member] \| Consumer Indirect [Member]
Major Classification of Loans Net of Unearned Income, Deferred Loan Origination Costs and Net Premiums on Acquired Loans [Abstract]
Loans	$ 533,727	$ 489,667

Number of portfolio segments through which the Company segregates and evaluates its loan portfolio.

No definition available.

Name:	ctbi_NumberOfPortfolioSegments
Namespace Prefix:	ctbi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

+ Details

Name:	us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ctbi_EquipmentLeaseFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ctbi_ConsumerDirectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ctbi_ConsumerIndirectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: