No definition available.

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

- Definition

This element represents the fair value disclosure of collateral dependent loan receivable as presented on the statement of financial position.

+ References

No definition available.

+ Details

Name:	ctbi_CollateralDependentLoansFairValueDisclosure
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount at which an asset could be bought or sold in a current transaction between willing parties, that is, other than in a forced or liquidation sale.

+ References

No definition available.

+ Details

Name:	ctbi_FairValueAdjustmentOnCollateralDependentLoans
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount at which an asset could be bought or sold in a current transaction between willing parties, that is, other than in a forced or liquidation sale.

+ References

No definition available.

+ Details

Name:	ctbi_FairValueAdjustmentOnOtherRealEstateOwned
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

This element represents the fair value disclosure of impaired loan receivable as presented on the statement of financial position which may include mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts, or any other loans which are due the Company as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	ctbi_ImpairedLoansFairValueDisclosure
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents mortgage servicing right at fair value.

+ References

No definition available.

+ Details

Name:	ctbi_MortgageServicingRightsFairValueDisclosure
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

No definition available.

+ Details

Name:	ctbi_OtherRealEstateOwnedFairValueDisclosure
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The frequency of periodic reviews for appraisals on foreclosed properties and other real estate owned generally, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

The typical frequency of periodic reviews for appraisals on foreclosed properties and other real estate owned, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563

+ Details

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

- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

+ Details

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

- Definition

Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

- Definition

Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

+ Details

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

- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

- Definition

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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

- References

No definition available.

+ Details

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

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=ctbi_MortgageServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Market Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	$ 740,479	$ 599,844		$ 740,479		$ 599,844
Equity securities at fair value	2,094	1,953		2,094		1,953
Assets measured-nonrecurring basis [Abstract]
Collateral dependent loans	3,030			3,030
Impaired loans		3,217				3,217
Reconciliation of beginning and ending balances of recurring fair value measurements recognized in balance sheet using significant unobservable (Level 3) inputs [Roll Forward]
Total losses	(6)		$ (263)	$ (1,165)	$ (241)
Minimum [Member]
Other real estate owned [Abstract]
Typical frequency of periodic reviews				12 months
Maximum [Member]
Other real estate owned [Abstract]
Typical frequency of periodic reviews				18 months
Frequency of periodic reviews in general				24 months
U.S. Treasury and Government Agencies [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	89,432	171,150		$ 89,432		171,150
State and Political Subdivisions [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	125,918	102,307		125,918		102,307
U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	469,955	295,245		469,955		295,245
Other Debt Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	55,174	31,142		55,174		31,142
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fair Value [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	3,498	54,263		3,498		54,263
Equity securities at fair value	0	0		0		0
Significant Other Observable Inputs (Level 2) [Member] \| Fair Value [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	736,981	545,581		736,981		545,581
Equity securities at fair value	0	0		0		0
Significant Unobservable Inputs (Level 3) [Member] \| Fair Value [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Equity securities at fair value	2,094	1,953		2,094		1,953
Recurring [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Equity securities at fair value	2,094	1,953		2,094		1,953
Mortgage servicing rights	2,518	3,263		2,518		3,263
Recurring [Member] \| U.S. Treasury and Government Agencies [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	89,432	171,150		89,432		171,150
Recurring [Member] \| State and Political Subdivisions [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	125,918	102,307		125,918		102,307
Recurring [Member] \| U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	469,955	295,245		469,955		295,245
Recurring [Member] \| Other Debt Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	55,174	31,142		55,174		31,142
Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Equity securities at fair value	0	0		0		0
Mortgage servicing rights	0	0		0		0
Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| U.S. Treasury and Government Agencies [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	3,498	54,263		3,498		54,263
Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| State and Political Subdivisions [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Other Debt Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Equity securities at fair value	0	0		0		0
Mortgage servicing rights	0	0		0		0
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| U.S. Treasury and Government Agencies [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	85,934	116,887		85,934		116,887
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| State and Political Subdivisions [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	125,918	102,307		125,918		102,307
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	469,955	295,245		469,955		295,245
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Other Debt Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	55,174	31,142		55,174		31,142
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Equity securities at fair value	2,094	1,953		2,094		1,953
Mortgage servicing rights	2,518	3,263		2,518		3,263
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| U.S. Treasury and Government Agencies [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| State and Political Subdivisions [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Other Debt Securities [Member]
Assets Measured at Fair Value on Recurring Basis [Abstract]
Debt securities available-for-sale	0	0		0		0
Recurring [Member] \| Equity Securities [Member]
Reconciliation of beginning and ending balances of recurring fair value measurements recognized in balance sheet using significant unobservable (Level 3) inputs [Roll Forward]
Beginning balance	1,721		1,528	1,953	1,173	1,173
Total unrealized gains (losses) included in net income	373		199	141	554
Issues	0		0	0	0
Settlements	0		0	0	0
Ending balance	2,094	1,953	1,727	2,094	1,727	1,953
Total gains (losses) for the period included in net income attributable to the change in unrealized gains or losses related to assets still held at the reporting date	373		199	141	554
Recurring [Member] \| Mortgage Servicing Rights [Member]
Reconciliation of beginning and ending balances of recurring fair value measurements recognized in balance sheet using significant unobservable (Level 3) inputs [Roll Forward]
Beginning balance	2,481		3,390	3,263	3,607	3,607
Total unrealized gains (losses) included in net income	(148)		(348)	(966)	(582)
Issues	415		191	560	307
Settlements	(230)		(114)	(339)	(213)
Ending balance	2,518	3,263	3,119	2,518	3,119	3,263
Total gains (losses) for the period included in net income attributable to the change in unrealized gains or losses related to assets still held at the reporting date	(148)		(348)	(966)	(582)
Nonrecurring [Member]
Impaired loan (collateral dependent) [Abstract]
Fair value adjustments on collateral dependent loans	900	400	200	1,400	500	700
Other real estate owned [Abstract]
Other real estate owned, fair value adjustment	200	700	$ 600	700	$ 1,000	3,200
Nonrecurring [Member] \| Fair Value [Member]
Assets measured-nonrecurring basis [Abstract]
Collateral dependent loans	3,030			3,030
Impaired loans		3,217				3,217
Other real estate owned	1,692	12,593		1,692		12,593
Nonrecurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fair Value [Member]
Assets measured-nonrecurring basis [Abstract]
Collateral dependent loans	0			0
Impaired loans		0				0
Other real estate owned	0	0		0		0
Nonrecurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Fair Value [Member]
Assets measured-nonrecurring basis [Abstract]
Collateral dependent loans	0			0
Impaired loans		0				0
Other real estate owned	0	0		0		0
Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fair Value [Member]
Assets measured-nonrecurring basis [Abstract]
Collateral dependent loans	3,030			3,030
Impaired loans		3,217				3,217
Other real estate owned	$ 1,692	$ 12,593		$ 1,692		$ 12,593