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Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2009
Summary Of Accounting Policies [Line Items]          
Maturity Period To Be Considered Cash Equivalents 3        
Inventory Write-down $ 681,000us-gaap_InventoryWriteDown        
Non-refundable contributions for construction received 813,000us-gaap_ContributionsInAidOfConstruction 785,000us-gaap_ContributionsInAidOfConstruction      
Allowed funds used during construction 58,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest 131,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest 111,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest    
Property, plant and equipment in service assets under operating lease contract 1,400,000us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross        
Annual revenue from operating lease 264,000us-gaap_OperatingLeasesIncomeStatementLeaseRevenue        
Operating lease term 20 years        
Accumulated depreciation, plant in service assets under operating lease 435,000us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAccumulatedDepreciation 363,000us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAccumulatedDepreciation      
Capital Leased Assets, Gross 6,100,000us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet 7,000,000us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet      
Ground Leases, Accumulated Amortization 996,000us-gaap_GroundLeasesAccumulatedAmortization 147,000us-gaap_GroundLeasesAccumulatedAmortization      
Amortization of Leased Asset 848,000us-gaap_AmortizationOfLeasedAsset 147,000us-gaap_AmortizationOfLeasedAsset      
Net property, plant and equipment 689,762,000us-gaap_PropertyPlantAndEquipmentNet 631,246,000us-gaap_PropertyPlantAndEquipmentNet      
Accumulated depreciation 193,369,000us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment 174,148,000us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment      
Depreciation and accretion reported in operations expenses 6,600,000us-gaap_DepreciationAmortizationAndAccretionNet 6,100,000us-gaap_DepreciationAmortizationAndAccretionNet 5,500,000us-gaap_DepreciationAmortizationAndAccretionNet    
Deferred revenue refund payment, period 1 year        
Asset Impairment Charges 6,881,000us-gaap_AssetImpairmentCharges 0us-gaap_AssetImpairmentCharges 0us-gaap_AssetImpairmentCharges    
Pensions and other employee benefits          
Summary Of Accounting Policies [Line Items]          
Percentage of change in discount rate 0.25%cpk_ChangeInDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= cpk_PensionAndOtherPostretirementBenefitsMember		        
Percentage of change in rate of return 0.25%cpk_PercentageIncreaseDecreaseInAssumedExpectedReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= cpk_PensionAndOtherPostretirementBenefitsMember		        
Estimated increase in annual pension and postretirement costs 18,000cpk_DefinedBenefitPlanNetPeriodicBenefitCostResultingFromDecreaseInDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= cpk_PensionAndOtherPostretirementBenefitsMember		        
Estimated decrease in annual pension and postretirement costs (22,000)cpk_DefinedBenefitPlanNetPeriodicBenefitCostResultingFromIncreaseInDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= cpk_PensionAndOtherPostretirementBenefitsMember		        
Estimated change in annual post retirement and supplemental executive retirement plans 134,000cpk_EstimatedIncreaseInExpenseResultingFromHypotheticalChangeInAssumptionExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= cpk_PensionAndOtherPostretirementBenefitsMember		        
Natural Gas Operations          
Summary Of Accounting Policies [Line Items]          
Net property, plant and equipment 6,700,000us-gaap_PropertyPlantAndEquipmentNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpk_NaturalGasOperationsMember		        
Length of pipeline 16cpk_MilesOfNaturalGasPipeline
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpk_NaturalGasOperationsMember		        
Ownership interest 4500.00%us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpk_NaturalGasOperationsMember		        
Accumulated depreciation 584,000us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpk_NaturalGasOperationsMember		 361,000us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpk_NaturalGasOperationsMember		      
Parent          
Summary Of Accounting Policies [Line Items]          
Premium paid for acquisition       746,000cpk_BusinessAcquisitionPremiumPaid
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		 34,200,000cpk_BusinessAcquisitionPremiumPaid
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Regulated Energy          
Summary Of Accounting Policies [Line Items]          
Asset Impairment Charges 6,400,000us-gaap_AssetImpairmentCharges
/ cpk_IMPAIREDASSETSAxis
= cpk_RegulatedEnergyMember		        
Unregulated Energy          
Summary Of Accounting Policies [Line Items]          
Asset Impairment Charges 19,000us-gaap_AssetImpairmentCharges
/ cpk_IMPAIREDASSETSAxis
= cpk_UnregulatedEnergyMember		        
Chesapeake [Member]          
Summary Of Accounting Policies [Line Items]          
Asset Impairment Charges 6,468,000us-gaap_AssetImpairmentCharges
/ cpk_IMPAIREDASSETSAxis
= cpk_ChesapeakeMember		        
Noncompete Agreements [Member]          
Summary Of Accounting Policies [Line Items]          
Impairment of Intangible Assets (Excluding Goodwill) $ 175,000us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_NoncompeteAgreementsMember