Allowance for Loan and Lease Losses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	$ 34,008	$ 33,245	$ 33,171
Provision charged to expense	8,755	8,568	9,450
Losses charged off	11,436	11,049	12,590
Recoveries	3,120	3,244	3,214
ALLL balance, end of year	34,447	34,008	33,245
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	1,742	2,296	3,248
Collectively evaluated for impairment	32,705	31,712	29,997
Loans Ending balance: [Abstract]
Individually evaluated for impairment	59,068	65,300	62,498
Collectively evaluated for impairment	2,674,756	2,550,054	2,488,075
Commercial Construction [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	3,396	4,033	4,023
Provision charged to expense	(513)	189	1,009
Losses charged off	15	1,135	1,034
Recoveries	28	309	35
ALLL balance, end of year	2,896	3,396	4,033
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	734	1,189	1,820
Collectively evaluated for impairment	2,162	2,207	2,213
Loans Ending balance: [Abstract]
Individually evaluated for impairment	9,627	9,810	9,395
Collectively evaluated for impairment	112,315	100,969	110,052
Commercial Secured by Real Estate [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	14,535	13,541	11,753
Provision charged to expense	941	2,438	3,520
Losses charged off	2,163	1,607	2,035
Recoveries	305	163	303
ALLL balance, end of year	13,618	14,535	13,541
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	827	1,005	1,090
Collectively evaluated for impairment	12,791	13,530	12,451
Loans Ending balance: [Abstract]
Individually evaluated for impairment	34,357	39,297	38,113
Collectively evaluated for impairment	914,269	833,245	769,100
Equipment Lease Financing [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	121	126	112
Provision charged to expense	(2)	(5)	14
Losses charged off	0	0	0
Recoveries	0	0	0
ALLL balance, end of year	119	121	126
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	119	121	126
Loans Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	10,344	8,840	9,246
Commercial Other [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	5,238	5,469	5,608
Provision charged to expense	1,545	1,477	2,330
Losses charged off	3,141	2,265	3,233
Recoveries	621	557	764
ALLL balance, end of year	4,263	5,238	5,469
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	181	102	338
Collectively evaluated for impairment	4,082	5,136	5,131
Loans Ending balance: [Abstract]
Individually evaluated for impairment	13,807	15,169	14,295
Collectively evaluated for impairment	338,241	359,712	362,053
Real Estate Construction [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	397	376	354
Provision charged to expense	258	106	183
Losses charged off	123	89	189
Recoveries	2	4	28
ALLL balance, end of year	534	397	376
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	534	397	376
Loans Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	62,412	56,075	55,041
Real Estate Mortgage [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	4,939	4,767	4,302
Provision charged to expense	2,173	860	1,437
Losses charged off	1,058	744	1,123
Recoveries	40	56	151
ALLL balance, end of year	6,094	4,939	4,767
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	6,094	4,939	4,767
Loans Ending balance: [Abstract]
Individually evaluated for impairment	1,277	1,024	695
Collectively evaluated for impairment	711,188	696,577	696,233
Home Equity [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	601	563	562
Provision charged to expense	265	268	238
Losses charged off	115	241	248
Recoveries	5	11	11
ALLL balance, end of year	756	601	563
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	756	601	563
Loans Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	88,335	84,880	82,292
Consumer Direct [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	1,127	1,102	917
Provision charged to expense	1,207	696	892
Losses charged off	1,326	1,166	1,245
Recoveries	566	495	538
ALLL balance, end of year	1,574	1,127	1,102
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	1,574	1,127	1,102
Loans Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	122,136	122,215	122,581
Consumer Indirect [Member]
Allowance for loan and lease losses [Roll Forward]
ALLL balance, beginning of year	3,654	3,268	5,540
Provision charged to expense	2,881	2,539	(173)
Losses charged off	3,495	3,802	3,483
Recoveries	1,553	1,649	1,384
ALLL balance, end of year	4,593	3,654	3,268
Allowance for Loan Losses Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	4,593	3,654	3,268
Loans Ending balance: [Abstract]
Individually evaluated for impairment	0	0	0
Collectively evaluated for impairment	$ 315,516	$ 287,541	$ 281,477

Name:	ctbi_LoanAbstract
Namespace Prefix:	ctbi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (h)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (h)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 11

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.11)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ctbi_CommercialOtherMember
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:

- Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateOtherReceivableMember
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_FinanceLeasesFinancingReceivableMember
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_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_MortgageLoansOnRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: