Regulatory Matters (Details) (USD $)	12 Months Ended
Dec. 31, 2014 Document	Dec. 31, 2013
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Restricted core capital elements (in hundredths)	25.00%ctbi_RestrictedCoreCapitalElements
Transition period of final rule	5 years
Tier I capital (to average assets), Amount [Abstract]
Actual Amount	$ 439,877,000us-gaap_TierOneLeverageCapital	$ 412,053,000us-gaap_TierOneLeverageCapital
For Capital Adequacy Purposes	146,139,000	143,198,000
Tier I capital (to average assets), Ratio [Abstract]
Actual Ratio (in hundredths)	12.04%	11.51%
For Capital Adequacy Purposes (in hundredths)	4.00%	4.00%
Tier I capital (to risk weighted assets), Amount [Abstract]
Actual Amount	439,877,000us-gaap_TierOneRiskBasedCapital	412,053,000us-gaap_TierOneRiskBasedCapital
For Capital Adequacy Purposes	106,572,000	102,056,000
Tier I capital (to risk weighted assets), Ratio [Abstract]
Actual Ratio (in hundredths)	16.51%	16.15%
For Capital Adequacy Purposes (in hundredths)	4.00%	4.00%
Total capital (to risk weighted assets), Amount [Abstract]
Actual Amount	473,097,000us-gaap_Capital	443,875,000us-gaap_Capital
For Capital Adequacy Purposes	213,107,000	204,080,000
Total capital (to risk-weighted assets), Ratio [Abstract]
Actual Ratio (in hundredths)	17.76%us-gaap_CapitalToRiskWeightedAssets	17.40%us-gaap_CapitalToRiskWeightedAssets
For Capital Adequacy Purposes (in hundredths)	8.00%	8.00%
Number of consultative documents released by the Basel Committee	2
Maximum countercyclical buffer specified as percentage of common equity Tier 1 capital (in hundredths)	2.50%
Assets threshold for advanced approach banks	250,000,000,000
Foreign exposures threshold for advanced approach banks	10,000,000,000
Total assets threshold for small depository institution	15,000,000,000
Minimum assets for top tier banking organizations for disclosure requirements	50,000,000,000
Minimum consolidated assets for banks to which top tier banking organizations apply	250,000,000,000
Community Trust Bank, Inc [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Maximum dividend without Approval	53,200,000
Tier I capital (to average assets), Amount [Abstract]
Actual Amount	416,861,000	392,932,000
For Capital Adequacy Purposes	145,374,000	142,496,000
To Be Well-Capitalized Under Prompt Corrective Action Provision	181,718,000	178,120,000
Tier I capital (to average assets), Ratio [Abstract]
Actual Ratio (in hundredths)	11.47%	11.03%
For Capital Adequacy Purposes (in hundredths)	4.00%	4.00%
To Be Well-Capitalized Under Prompt Corrective Action Provision (in hundredths)	5.00%	5.00%
Tier I capital (to risk weighted assets), Amount [Abstract]
Actual Amount	416,861,000	392,932,000
For Capital Adequacy Purposes	106,274,000	101,730,000
To Be Well-Capitalized Under Prompt Corrective Action Provision	159,411,000	152,595,000
Tier I capital (to risk weighted assets), Ratio [Abstract]
Actual Ratio (in hundredths)	15.69%	15.45%
For Capital Adequacy Purposes (in hundredths)	4.00%	4.00%
To Be Well-Capitalized Under Prompt Corrective Action Provision (in hundredths)	6.00%	6.00%
Total capital (to risk weighted assets), Amount [Abstract]
Actual Amount	450,081,000	424,754,000
For Capital Adequacy Purposes	212,553,000	203,475,000
To Be Well-Capitalized Under Prompt Corrective Action Provision	$ 265,691,000	$ 254,344,000
Total capital (to risk-weighted assets), Ratio [Abstract]
Actual Ratio (in hundredths)	16.94%	16.70%
For Capital Adequacy Purposes (in hundredths)	8.00%	8.00%
To Be Well-Capitalized Under Prompt Corrective Action Provision (in hundredths)	10.00%	10.00%
CTBI and CTB [Member] \| Rules in 2015 [Member]
Tier I capital (to risk weighted assets), Ratio [Abstract]
To Be Well-Capitalized Under Prompt Corrective Action Provision (in hundredths)	8.00%
Total capital (to risk-weighted assets), Ratio [Abstract]
To Be Well-Capitalized Under Prompt Corrective Action Provision (in hundredths)	10.00%
Common equity Tier 1 capital ratio under well capitalized (in hundredths)	6.50%
Tier 1 leverage ratio under well capitalized (in hundredths)	5.00%
CTBI and CTB [Member] \| Rules from 2015 to 2019 [Member]
Tier I capital (to risk weighted assets), Ratio [Abstract]
For Capital Adequacy Purposes (in hundredths)	6.00%
Total capital (to risk-weighted assets), Ratio [Abstract]
For Capital Adequacy Purposes (in hundredths)	8.00%
Common equity Tier one capital ratio (in hundredths)	4.50%
Tier 1 leverage ratio (in hundredths)	4.00%
Capital conservation buffer in 2016 (in hundredths)	0.625%
Capital conservation buffer in 2017 (in hundredths)	1.25%
Capital conservation buffer in 2018 (in hundredths)	1.875%
Capital conservation buffer in 2019 and thereafter (in hundredths)	2.50%
CTBI and CTB [Member] \| Rules in 2019 [Member]
Tier I capital (to risk weighted assets), Ratio [Abstract]
For Capital Adequacy Purposes (in hundredths)	8.50%
Total capital (to risk-weighted assets), Ratio [Abstract]
For Capital Adequacy Purposes (in hundredths)	10.50%
Common equity Tier one capital ratio (in hundredths)	7.00%

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This line item represents the capital conservation buffer in year four and thereafter established by final rules.

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This line item represents the capital conservation buffer in year three established by final rules.

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This line item represents the capital conservation buffer in year two established by final rules.

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Common equity Tier 1 capital ratio required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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This line item represents the foreign exposures threshold for advanced approach banks.

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This line item represents the maximum countercyclical buffer specified as percentage of common equity Tier 1 capital.

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Maximum dividend that can be paid by the entity as per regulations limit.

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This line item represents the minimum assets for top tier banking organizations for disclosure requirements.

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This line item represents the minimum consolidated assets for banks to which top tier banking organizations apply.

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This line item represents the number of consultative documents released by the Basel Committee.

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Maximum percentage of restricted core capital limit for all bank holding companies, under the final rule.

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This line item represents Tier 1 leverage ratio as defined in the regulations.

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Tier 1 leverage ratio required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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This line item represents the total assets threshold for small depository institution.

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Refers to the transaction period of final rule.

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The amount of total capital as defined in the regulations.

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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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