Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Activity for other real estate owned [Roll Forward]
Beginning balance of other real estate owned	$ 27,273	$ 31,996
New assets acquired	854	1,284
Fair value adjustments	(447)	(467)
Sale of assets	(2,710)	(809)
Ending balance of other real estate owned	24,970	32,004
Carrying cost and fair value adjustments for foreclosed properties	$ 800	$ 900

This element represent the carrying cost and fair value adjustments of foreclosed properties.

No definition available.

Name:	ctbi_CarryingCostAndFairValueAdjustmentForForeclosedProperties1
Namespace Prefix:	ctbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the fair value adjustment to other real stated owned.

+ References

No definition available.

+ Details

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

- Definition

Amount of real estate investments acquired including foreclosure during the period.

+ References

No definition available.

+ Details

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

- Definition

Carrying amount as of the balance sheet date of other real estate and foreclosed assets. Other real estate may include real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Amount of real estate investments sold for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 970
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28(Footnote 4))
-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

+ Details

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