Loans, Impaired Loans, Average Investments in Impaired Loans, and Interest Income Recognized on Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Total impaired loans [Abstract]
Recorded balance	$ 62,498	$ 47,110	$ 63,309
Unpaid Contractual Principal Balance	68,596	53,378	67,212
Specific Allowance	3,248	4,669	8,222
Average investment in impaired loans	62,624	61,363	63,005
Interest Income Recognized	1,880	1,983	531
Commercial Construction [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	3,692	4,778	6,313
Unpaid Contractual Principal Balance	4,146	4,778	6,313
Specific Allowance	0	0	0
Average Investment in Impaired Loans	4,249	8,992	6,262
Interest Income Recognized	97	252	43
Loans with a specific valuation allowance [Abstract]
Recorded Balance	5,703	5,794	9,528
Unpaid Contractual Principal Balance	6,933	6,643	10,813
Specific Allowance	1,820	2,203	2,554
Average Investment in Impaired Loans	6,585	7,681	9,686
Interest income recognized	0	0	0
Commercial Secured by Real Estate [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	35,046	27,811	23,503
Unpaid Contractual Principal Balance	35,818	29,765	24,034
Specific Allowance	0	0	0
Average Investment in Impaired Loans	35,542	31,480	23,629
Interest Income Recognized	1,337	1,543	330
Loans with a specific valuation allowance [Abstract]
Recorded Balance	3,067	3,525	9,188
Unpaid Contractual Principal Balance	3,189	3,669	9,358
Specific Allowance	1,090	1,156	2,575
Average Investment in Impaired Loans	3,243	4,747	9,191
Interest income recognized	0	23	2
Commercial Other [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	13,285	1,770	4,357
Unpaid Contractual Principal Balance	15,484	2,501	4,616
Specific Allowance	0	0	0
Average Investment in Impaired Loans	11,083	3,392	4,407
Interest Income Recognized	416	143	71
Loans with a specific valuation allowance [Abstract]
Recorded Balance	1,010	3,432	8,680
Unpaid Contractual Principal Balance	2,331	6,022	10,338
Specific Allowance	338	1,310	3,093
Average Investment in Impaired Loans	1,441	5,071	8,090
Interest income recognized	0	22	85
Residential [Member]
Total impaired loans [Abstract]
Recorded balance	695		1,740
Unpaid Contractual Principal Balance	695		1,740
Specific Allowance	0		0
Average investment in impaired loans	481		1,740
Interest Income Recognized	30		0
Real Estate Construction [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance			790
Unpaid Contractual Principal Balance			790
Specific Allowance			0
Average Investment in Impaired Loans			790
Interest Income Recognized			0
Real Estate Mortgage [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	695		950
Unpaid Contractual Principal Balance	695		950
Specific Allowance	0		0
Average Investment in Impaired Loans	481		950
Interest Income Recognized	30		0
Commerical [Member]
Total impaired loans [Abstract]
Recorded balance	61,803	47,110	61,569
Unpaid Contractual Principal Balance	67,901	53,378	65,472
Specific Allowance	3,248	4,669	8,222
Average investment in impaired loans	62,143	61,363	61,265
Interest Income Recognized	$ 1,850	$ 1,983	$ 531

Amount of allowance for credit losses related to recorded investment.

No definition available.

Name:	ctbi_ImpairedFinancingReceivableRelatedAllowance1
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Details

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

- Definition

Refers to Specific Allowance.

+ References

No definition available.

+ Details

Name:	ctbi_SpecificAllowance
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5212-111524

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5258-111524

+ Details

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

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

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

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953550-111524

+ Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

+ References

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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