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Employee Benefit Plans (Narrative) (Details) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Incentive stock options and SARs exercisable period | 10 years |  |
Stock awards had been awarded | 411,601 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber |  |
Proceeds from exercise of stock options | $ 600,000 us-gaap_ProceedsFromStockOptionsExercised | $ 4,200,000 us-gaap_ProceedsFromStockOptionsExercised | $ 500,000 us-gaap_ProceedsFromStockOptionsExercised
Total intrinsic value of stock options exercised | 300,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue | 900,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue | 100,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Stock-based compensation expense | 200,000 us-gaap_AllocatedShareBasedCompensationExpense | 200,000 us-gaap_AllocatedShareBasedCompensationExpense | 200,000 us-gaap_AllocatedShareBasedCompensationExpense
Income tax benefit recognized related to stock-based compensation |  | 300,000 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions |
Unrecognized stock-based compensation expense | 400,000 us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized |  |
Weighted-average period, unrecognized expense expected to be recognized | 1 year 6 months 6 days |  |
Stock-based compensation expense related to restricted shares | 1,000,000 us-gaap_RestrictedStockExpense | 800,000 us-gaap_RestrictedStockExpense | 600,000 us-gaap_RestrictedStockExpense
Total expense associated with the retirement benefit plan | 800,000 us-gaap_DefinedContributionPlanCostRecognized | 800,000 us-gaap_DefinedContributionPlanCostRecognized | 600,000 us-gaap_DefinedContributionPlanCostRecognized
Number of shares of the Company's common stock held by the 401(k) | 303,443 chco_CommonStockSharesHeldInBenefitPlan | 271,749 chco_CommonStockSharesHeldInBenefitPlan |
Recorded a pension liability | 6,800,000 us-gaap_DefinedBenefitPensionPlanLiabilitiesCurrent | 2,800,000 us-gaap_DefinedBenefitPensionPlanLiabilitiesCurrent |
Underfunded pension liability | 5,300,000 us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesAfterTax | 2,900,000 us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesAfterTax |
Anticipated next year plan contributions | 400,000 us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear |  |
Executive officers accrued benefit liability | 2,000,000 chco_ExecutiveOfficersAccruedBenefitLiability | 2,000,000 chco_ExecutiveOfficersAccruedBenefitLiability |
Deferred compensation agreement costs | 200,000 us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense | 200,000 us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense | 200,000 us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense
Deferred compensation agreement liabilities | 6,700,000 us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability | 7,000,000 us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability |
Cash surrender value of company owned life insurance | 7,800,000 us-gaap_CashSurrenderValueOfLifeInsurance | 7,600,000 us-gaap_CashSurrenderValueOfLifeInsurance |
Non-Vested Restricted Shares |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Unrecognized stock-based compensation expense | 2,900,000 us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized / us-gaap_AwardTypeAxis = chco_NonVestedRestrictedSharesMember |  |
Weighted-average period, unrecognized expense expected to be recognized | 3 years 4 months 24 days |  |
Restricted Stock |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Stock awards had been awarded | 216,156 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = us-gaap_RestrictedStockMember |  |
Maximum |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Common stock issued upon the exercise of stock options, SARs and stock awards | 750,000 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized / us-gaap_RangeAxis = us-gaap_MaximumMember |  |
Income tax benefit recognized related to stock-based compensation | $ 100,000 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions / us-gaap_RangeAxis = us-gaap_MaximumMember |  | $ 100,000 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions / us-gaap_RangeAxis = us-gaap_MaximumMember
Horizon Defined Benefit Plan |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Overall investment return goal above stated indices | 0.50%chco_InvestmentReturnGoalAboveStatedIndicies / us-gaap_MultiemployerPlanNameAxis = chco_HorizonDefinedBenefitPlanMemberMember |  |
Moving average basis | 5 years |  |
Maximum percent of plan assets in any one security | 15.00%chco_DefinedBenefitPlanMaximumPercentOfAssetsInAnyOneCompany / us-gaap_MultiemployerPlanNameAxis = chco_HorizonDefinedBenefitPlanMemberMember |  |
Maximum percent of plan assets in any on industry | 25.00%chco_DefinedBenefitPlanMaximumPercentOfAssetsInAnyOneIndustry / us-gaap_MultiemployerPlanNameAxis = chco_HorizonDefinedBenefitPlanMemberMember |  |
Maximum percent of plan assets in foreign securities | 25.00%chco_DefinedBenefitPlanMaximumPercentOfAssetsInForeignSecurities / us-gaap_MultiemployerPlanNameAxis = chco_HorizonDefinedBenefitPlanMemberMember |  |
Community Defined Benefit Plan |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Defined benefit plan, allocation allowance | 5.00%chco_DefinedBenefitPlanAllocationAllowance / us-gaap_MultiemployerPlanNameAxis = chco_CommunityDefinedBenefitPlanMember |  |
Community Defined Benefit Plan | Maximum |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Moving average basis | 5 years |  |
Allocation for sub-asset class within equity and fixed classes | 150.00%chco_AllocationforSubAssetClassWithinEquityandFixedClasses / us-gaap_MultiemployerPlanNameAxis = chco_CommunityDefinedBenefitPlanMember / us-gaap_RangeAxis = us-gaap_MaximumMember |  |
Community Defined Benefit Plan | Minimum |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Moving average basis | 3 years |  |
Allocation for sub-asset class within equity and fixed classes | 50.00%chco_AllocationforSubAssetClassWithinEquityandFixedClasses / us-gaap_MultiemployerPlanNameAxis = chco_CommunityDefinedBenefitPlanMember / us-gaap_RangeAxis = us-gaap_MinimumMember |  |
Pentegra Defined Benefit Plan for Financial Institutions |  |  |
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] |  |  |
Defined Benefit Plan, Funded Percentage | 109.13%us-gaap_DefinedBenefitPlanFundedPercentage / us-gaap_MultiemployerPlanNameAxis = chco_PentegraDefinedBenefitPlanforFinancialInstitutionsMember |  |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
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- Definition Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 4 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6812-107765 + Details
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- Definition Unrecognized cost of unvested share-based compensation awards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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