$CPK
CHESAPEAKE UTILITIES CORP Stock $cpk

$cpk Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000162828021003104 Filed on February 24, 2021

Income Statement

Concept	2020 Q4	2019 Q4	2019 Q3
Revenue	$137.0M	$132.0M	$92.63M
YoY Change	3.84%	-1.67%	-0.83%
Cost Of Revenue	$40.20M	$43.10M	$25.30M
YoY Change	-6.73%	-15.82%	-18.39%
Gross Profit	$96.80M	$88.90M	$67.30M
YoY Change	8.89%	7.11%	7.85%
Gross Profit Margin	70.64%	67.36%	72.66%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$15.30M	$11.90M	$11.30M
YoY Change	28.57%	12.26%	6.27%
% of Gross Profit	15.81%	13.39%	16.79%
Operating Expenses	$61.60M	$59.20M	$78.27M
YoY Change	4.05%	9.43%	-2.8%
Operating Profit	$35.21M	$29.64M	$14.36M
YoY Change	18.77%	2.66%	11.48%
Interest Expense	-$6.300M	-$5.600M	$5.403M
YoY Change	12.5%	27.27%	24.01%
% of Operating Profit	-17.89%	-18.89%	37.63%
Other Income/Expense, Net	$200.0K	-$1.100M	-$351.0K
YoY Change	-118.18%	175.0%	8675.0%
Pretax Income	$29.10M	$22.90M	$8.603M
YoY Change	27.07%	-4.98%	1.0%
Income Tax	$7.500M	$5.800M	$2.352M
% Of Pretax Income	25.77%	25.33%	27.34%
Net Earnings	$22.56M	$22.56M	$5.621M
YoY Change	0.0%	26.76%	1.5%
Net Earnings / Revenue	16.47%	17.1%	6.07%
Basic Earnings Per Share	$1.38	$1.38	$0.34
Diluted Earnings Per Share	$1.37	$1.37	$0.34
COMMON SHARES
Basic Shares Outstanding	17.46M shares	16.40M shares	16.40M shares
Diluted Shares Outstanding			16.45M shares

Balance Sheet

Concept	2020 Q4	2019 Q4	2019 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$3.500M	$7.000M	$4.300M
YoY Change	-50.0%	14.75%	-30.65%
Cash & Equivalents	$3.499M	$6.985M	$4.320M
Short-Term Investments
Other Short-Term Assets	$436.0K	$2.879M	$2.489M
YoY Change	-84.86%	-49.33%	-2.66%
Inventory	$13.90M	$15.40M	$12.60M
Prepaid Expenses	$13.24M	$13.93M	$10.57M
Receivables	$56.89M	$49.56M	$34.50M
Other Receivables	$12.90M	$20.10M	$11.10M
Total Short-Term Assets	$136.4M	$134.8M	$114.9M
YoY Change	1.19%	-29.61%	-10.92%
LONG-TERM ASSETS
Property, Plant & Equipment	$1.601B	$1.464B	$1.461B
YoY Change	9.39%	8.15%	15.64%
Goodwill	$38.73M	$32.67M	$21.52M
YoY Change	18.56%	51.47%	9.75%
Intangibles	$8.292M	$8.129M	$3.272M
YoY Change	2.01%	111.14%	-19.67%
Long-Term Investments	$10.80M	$9.200M	$8.500M
YoY Change	17.39%	37.31%	6.25%
Other Assets	$113.8M	$73.40M	$84.20M
YoY Change	55.04%	1.38%	10.35%
Total Long-Term Assets	$1.796B	$1.648B	$1.599B
YoY Change	8.96%	9.74%	16.18%
TOTAL ASSETS
Total Short-Term Assets	$136.4M	$134.8M	$114.9M
Total Long-Term Assets	$1.796B	$1.648B	$1.599B
Total Assets	$1.932B	$1.783B	$1.714B
YoY Change	8.37%	5.29%	13.86%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$60.25M	$54.07M	$53.15M
YoY Change	11.44%	-45.21%	-11.75%
Accrued Expenses	$32.10M	$30.90M	$30.50M
YoY Change	3.88%	6.19%	4.45%
Deferred Revenue	$644.0K	$589.0K	$774.0K
YoY Change	9.34%	22.71%	32.76%
Short-Term Debt	$175.6M	$247.4M	$224.7M
YoY Change	-29.02%	-15.99%	-16.23%
Long-Term Debt Due	$13.60M	$45.60M	$75.60M
YoY Change	-70.18%	282.07%	686.44%
Total Short-Term Liabilities	$329.0M	$423.3M	$446.2M
YoY Change	-22.27%	-19.86%	4.47%
LONG-TERM LIABILITIES
Long-Term Debt	$508.5M	$440.2M	$375.8M
YoY Change	15.52%	39.28%	55.55%
Other Long-Term Liabilities	$4.903M	$2.796M	$3.019M
YoY Change	75.36%	-5.8%	-2.27%
Total Long-Term Liabilities	$513.4M	$443.0M	$378.8M
YoY Change	15.9%	38.87%	54.82%
TOTAL LIABILITIES
Total Short-Term Liabilities	$329.0M	$423.3M	$446.2M
Total Long-Term Liabilities	$513.4M	$443.0M	$378.8M
Total Liabilities	$842.4M	$866.3M	$825.1M
YoY Change	-2.75%	2.25%	22.81%
SHAREHOLDERS EQUITY
Retained Earnings	$343.0M	$300.6M	$284.7M
YoY Change	14.09%	14.94%	13.97%
Common Stock	$357.0M	$267.2M	$265.4M
YoY Change	33.58%	1.37%	0.74%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$5.679M	$4.543M	$4.505M
YoY Change	25.01%	17.88%	17.99%
Treasury Stock Shares
Shareholders Equity	$697.1M	$561.6M	$544.7M
YoY Change
Total Liabilities & Shareholders Equity	$1.932B	$1.783B	$1.714B
YoY Change	8.37%	5.29%	13.86%

Cashflow Statement

Concept	2020 Q4	2019 Q4	2019 Q3
OPERATING ACTIVITIES
Net Income	$22.56M	$22.56M	$5.621M
YoY Change	0.0%	26.76%	1.5%
Depreciation, Depletion And Amortization	$15.30M	$11.90M	$11.30M
YoY Change	28.57%	12.26%	6.27%
Cash From Operating Activities	$43.00M	-$900.0K	$29.30M
YoY Change	-4877.78%	-91.51%	49.49%
INVESTING ACTIVITIES
Capital Expenditures	-$42.10M	-$45.40M	-$48.90M
YoY Change	-7.27%	-34.2%	9.64%
Acquisitions
YoY Change
Other Investing Activities	-$3.000M	-$1.300M	-$200.0K
YoY Change	130.77%	-92.22%
Cash From Investing Activities	-$45.00M	-$46.70M	-$49.00M
YoY Change	-3.64%	-45.44%	10.11%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	2.500M	50.30M	16.70M
YoY Change	-95.03%	-47.71%	-37.22%
NET CHANGE
Cash From Operating Activities	43.00M	-900.0K	29.30M
Cash From Investing Activities	-45.00M	-46.70M	-49.00M
Cash From Financing Activities	2.500M	50.30M	16.70M
Net Change In Cash	500.0K	2.700M	-3.000M
YoY Change	-81.48%	-13177740567272900.0%	-276.47%
FREE CASH FLOW
Cash From Operating Activities	$43.00M	-$900.0K	$29.30M
Capital Expenditures	-$42.10M	-$45.40M	-$48.90M
Free Cash Flow	$85.10M	$44.50M	$78.20M
YoY Change	91.24%	-23.8%	21.81%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2020	dei	Entity Registrant Name EntityRegistrantName	CHESAPEAKE UTILITIES CORP
CY2020	dei	Trading Symbol TradingSymbol	CPK
CY2020	dei	Entity Central Index Key EntityCentralIndexKey	0000019745
CY2020	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Period End Date DocumentPeriodEndDate	2020-12-31
CY2020	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2020	dei	Amendment Flag AmendmentFlag	false
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2020	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2020	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax	-18000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax	-20148	USD
CY2018	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax	-22000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax	41000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax	-368387	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax	49000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	1392000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-176000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-555000	USD
CY2020	cpk	Other Comprehensive Income Loss Unrealized Gain Loss On Interest Rate Swaps During Period Tax OtherComprehensiveIncomeLossUnrealizedGainLossOnInterestRateSwapsDuringPeriodTax	-12000	USD
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000	shares
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.4867
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.4867
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2020Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2019Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.7250
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.5850
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.4350
CY2020	cpk	Numberof Monthsto Establish Rou Assetand Liability NumberofMonthstoEstablishROUAssetandLiability	P12M
CY2020	cpk	Lengthoftimeuntildeferredamountsrecoveredorrefunded Lengthoftimeuntildeferredamountsrecoveredorrefunded	1
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2020	cpk	Number Of Unsecured Bank Credit Facilities NumberOfUnsecuredBankCreditFacilities	3
CY2020	us-gaap	Deferred Compensation Arrangement With Individual Requisite Service Period1 DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1	P2Y
CY2020	us-gaap	Deferred Compensation Arrangement With Individual Requisite Service Period1 DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1	P2Y
CY2020	cpk	Companys Exposure In Number Of Former Manufactured Gas Plant Sites CompanysExposureInNumberOfFormerManufacturedGasPlantSites	7	site
CY2020	us-gaap	Intercompany Agreements Description IntercompanyAgreementsDescription	three years
CY2020	cpk	Maximum Days To Make Default Good MaximumDaysToMakeDefaultGood	P5D
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Entity File Number EntityFileNumber	001-11590
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	51-0064146
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	909 Silver Lake Boulevard
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	Dover
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	DE
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	19904
CY2020	dei	City Area Code CityAreaCode	302
CY2020	dei	Local Phone Number LocalPhoneNumber	734-6799
CY2020	dei	Security12b Title Security12bTitle	Common Stock—par value per share $0.4867
CY2020	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2020	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2020	dei	Entity Small Business EntitySmallBusiness	false
CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020	dei	Entity Shell Company EntityShellCompany	false
CY2020	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2020Q2	dei	Entity Public Float EntityPublicFloat	1300000000	USD
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	17473124	shares
CY2020	us-gaap	Regulated Operating Revenue RegulatedOperatingRevenue	352746000	USD
CY2019	us-gaap	Regulated Operating Revenue RegulatedOperatingRevenue	343006000	USD
CY2018	us-gaap	Regulated Operating Revenue RegulatedOperatingRevenue	345281000	USD
CY2020	us-gaap	Unregulated Operating Revenue UnregulatedOperatingRevenue	152526000	USD
CY2019	us-gaap	Unregulated Operating Revenue UnregulatedOperatingRevenue	154151000	USD
CY2018	us-gaap	Unregulated Operating Revenue UnregulatedOperatingRevenue	161905000	USD
CY2020	cpk	Other Operating Revenue OtherOperatingRevenue	-17074000	USD
CY2019	cpk	Other Operating Revenue OtherOperatingRevenue	-17552000	USD
CY2018	cpk	Other Operating Revenue OtherOperatingRevenue	-16870000	USD
CY2020	us-gaap	Revenues Revenues	488198000	USD
CY2019	us-gaap	Revenues Revenues	479605000	USD
CY2018	us-gaap	Revenues Revenues	490316000	USD
CY2020	cpk	Regulated Energy Cost Of Sales RegulatedEnergyCostOfSales	91994000	USD
CY2019	cpk	Regulated Energy Cost Of Sales RegulatedEnergyCostOfSales	102803000	USD
CY2018	cpk	Regulated Energy Cost Of Sales RegulatedEnergyCostOfSales	121828000	USD
CY2020	cpk	Unregulated Energy And Other Cost Of Sales UnregulatedEnergyAndOtherCostOfSales	45944000	USD
CY2019	cpk	Unregulated Energy And Other Cost Of Sales UnregulatedEnergyAndOtherCostOfSales	51698000	USD
CY2018	cpk	Unregulated Energy And Other Cost Of Sales UnregulatedEnergyAndOtherCostOfSales	68341000	USD
CY2020	cpk	Operations Operations	142055000	USD
CY2019	cpk	Operations Operations	137845000	USD
CY2018	cpk	Operations Operations	132523000	USD
CY2020	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	15587000	USD
CY2019	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	15679000	USD
CY2018	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	14387000	USD
CY2020	cpk	Settlement Gain SettlementGain	130000	USD
CY2019	cpk	Settlement Gain SettlementGain	130000	USD
CY2018	cpk	Settlement Gain SettlementGain	130000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	58117000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	45424000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	40220000	USD
CY2020	us-gaap	Taxes Other TaxesOther	21908000	USD
CY2019	us-gaap	Taxes Other TaxesOther	20001000	USD
CY2018	us-gaap	Taxes Other TaxesOther	18303000	USD
CY2020	us-gaap	Operating Expenses OperatingExpenses	375475000	USD
CY2019	us-gaap	Operating Expenses OperatingExpenses	373320000	USD
CY2018	us-gaap	Operating Expenses OperatingExpenses	395472000	USD
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	112723000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	106285000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	94844000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	3222000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-1847000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-607000	USD
CY2020	us-gaap	Interest Expense InterestExpense	21765000	USD
CY2019	us-gaap	Interest Expense InterestExpense	22224000	USD
CY2018	us-gaap	Interest Expense InterestExpense	16146000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	94180000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	82214000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	78091000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	23538000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21114000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21123000	USD
CY2020	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	70642000	USD
CY2019	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	61100000	USD
CY2018	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	56968000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	686000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1349000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-388000	USD
CY2020	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	170000	USD
CY2019	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	5402000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	65153000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	56580000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16711579	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16398443	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16369616	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16770735	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16448486	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16419870	shares
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	4.23
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	3.73
CY2018	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	3.48
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.05
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.24
CY2018	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.02
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.28
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.97
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.46
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	4.21
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	3.72
CY2018	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	3.47
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0.05
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0.24
CY2018	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	-0.02
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.26
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.96
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.45
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	65153000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	56580000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax	-59000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax	-57000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax	-55000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1534000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	154000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-1052000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	108000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	3643000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-434000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-1371000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-28000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3402000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	561000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	74900000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	65714000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	55046000	USD
CY2020Q4	us-gaap	Public Utilities Property Plant And Equipment Plant In Service PublicUtilitiesPropertyPlantAndEquipmentPlantInService	1577576000	USD
CY2019Q4	us-gaap	Public Utilities Property Plant And Equipment Plant In Service PublicUtilitiesPropertyPlantAndEquipmentPlantInService	1441473000	USD
CY2020Q4	cpk	Unregulated Energy Property Plant And Equipment UnregulatedEnergyPropertyPlantAndEquipment	300647000	USD
CY2019Q4	cpk	Unregulated Energy Property Plant And Equipment UnregulatedEnergyPropertyPlantAndEquipment	265209000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	30769000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	39850000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1908992000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1746532000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	368743000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	336876000	USD
CY2020Q4	cpk	Construction Work In Progress ConstructionWorkInProgress	60929000	USD
CY2019Q4	cpk	Construction Work In Progress ConstructionWorkInProgress	54141000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1601178000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1463797000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	3499000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	6985000	USD
CY2020Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	61675000	USD
CY2019Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	50899000	USD
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	4785000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	1337000	USD
CY2020Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	56890000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	49562000	USD
CY2020Q4	cpk	Accrued Revenue AccruedRevenue	21527000	USD
CY2019Q4	cpk	Accrued Revenue AccruedRevenue	20846000	USD
CY2020Q4	us-gaap	Energy Related Inventory Propane Gas EnergyRelatedInventoryPropaneGas	5906000	USD
CY2019Q4	us-gaap	Energy Related Inventory Propane Gas EnergyRelatedInventoryPropaneGas	5824000	USD
CY2020Q4	us-gaap	Other Inventory OtherInventory	5539000	USD
CY2019Q4	us-gaap	Other Inventory OtherInventory	6067000	USD
CY2020Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	10786000	USD
CY2019Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	5144000	USD
CY2020Q4	us-gaap	Energy Related Inventory Natural Gas In Storage EnergyRelatedInventoryNaturalGasInStorage	2455000	USD
CY2019Q4	us-gaap	Energy Related Inventory Natural Gas In Storage EnergyRelatedInventoryNaturalGasInStorage	3541000	USD
CY2020Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	12885000	USD
CY2019Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	20050000	USD
CY2020Q4	us-gaap	Prepaid Expense Current PrepaidExpenseCurrent	13239000	USD
CY2019Q4	us-gaap	Prepaid Expense Current PrepaidExpenseCurrent	13928000	USD
CY2020Q4	us-gaap	Energy Marketing Contracts Assets Current EnergyMarketingContractsAssetsCurrent	3269000	USD
CY2019Q4	us-gaap	Energy Marketing Contracts Assets Current EnergyMarketingContractsAssetsCurrent	0	USD
CY2020Q4	us-gaap	Other Assets Current OtherAssetsCurrent	436000	USD
CY2019Q4	us-gaap	Other Assets Current OtherAssetsCurrent	2879000	USD
CY2020Q4	us-gaap	Assets Current AssetsCurrent	136431000	USD
CY2019Q4	us-gaap	Assets Current AssetsCurrent	134826000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	38731000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	32668000	USD
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	8292000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	8129000	USD
CY2020Q4	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	10776000	USD
CY2019Q4	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	9229000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11194000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11563000	USD
CY2020Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	113806000	USD
CY2019Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	73407000	USD
CY2020Q4	cpk	Receivables And Other Deferred Charges ReceivablesAndOtherDeferredCharges	12079000	USD
CY2019Q4	cpk	Receivables And Other Deferred Charges ReceivablesAndOtherDeferredCharges	49579000	USD
CY2020Q4	cpk	Deferred Charges And Other Assets DeferredChargesAndOtherAssets	194878000	USD
CY2019Q4	cpk	Deferred Charges And Other Assets DeferredChargesAndOtherAssets	184575000	USD
CY2020Q4	us-gaap	Assets Assets	1932487000	USD
CY2019Q4	us-gaap	Assets Assets	1783198000	USD
CY2020Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2019Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	8499000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	7984000	USD
CY2020Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	348482000	USD
CY2019Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	259253000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	342969000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	300607000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-2865000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-6267000	USD
CY2020Q4	us-gaap	Compensation And Benefits Trust CompensationAndBenefitsTrust	5679000	USD
CY2019Q4	us-gaap	Compensation And Benefits Trust CompensationAndBenefitsTrust	4543000	USD
CY2020Q4	us-gaap	Treasury Stock Value TreasuryStockValue	5679000	USD
CY2019Q4	us-gaap	Treasury Stock Value TreasuryStockValue	4543000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	697085000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	561577000	USD
CY2020Q4	cpk	Longterm Debtand Capital Lease Obligations Netof Current Maturities LongtermDebtandCapitalLeaseObligationsNetofCurrentMaturities	508499000	USD
CY2019Q4	cpk	Longterm Debtand Capital Lease Obligations Netof Current Maturities LongtermDebtandCapitalLeaseObligationsNetofCurrentMaturities	440168000	USD
CY2020Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	1205584000	USD
CY2019Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	1001745000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	13600000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	45600000	USD
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	175644000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	247371000	USD
CY2020Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	60253000	USD
CY2019Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	54068000	USD
CY2020Q4	us-gaap	Contract With Customer Refund Liability Current ContractWithCustomerRefundLiabilityCurrent	33302000	USD
CY2019Q4	us-gaap	Contract With Customer Refund Liability Current ContractWithCustomerRefundLiabilityCurrent	30939000	USD
CY2020Q4	us-gaap	Interest Payable Current InterestPayableCurrent	2905000	USD
CY2019Q4	us-gaap	Interest Payable Current InterestPayableCurrent	2554000	USD
CY2020Q4	us-gaap	Dividends Payable Current DividendsPayableCurrent	7683000	USD
CY2019Q4	us-gaap	Dividends Payable Current DividendsPayableCurrent	6644000	USD
CY2020Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	13994000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	16236000	USD
CY2020Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	6284000	USD
CY2019Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	5991000	USD
CY2020Q4	us-gaap	Energy Marketing Contract Liabilities Current EnergyMarketingContractLiabilitiesCurrent	127000	USD
CY2019Q4	us-gaap	Energy Marketing Contract Liabilities Current EnergyMarketingContractLiabilitiesCurrent	1844000	USD
CY2020Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	15240000	USD
CY2019Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	12077000	USD
CY2020Q4	us-gaap	Liabilities Current LiabilitiesCurrent	329032000	USD
CY2019Q4	us-gaap	Liabilities Current LiabilitiesCurrent	423324000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	205388000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	180656000	USD
CY2020Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	142736000	USD
CY2019Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	127744000	USD
CY2020Q4	us-gaap	Accrued Environmental Loss Contingencies Noncurrent AccruedEnvironmentalLossContingenciesNoncurrent	4299000	USD
CY2019Q4	us-gaap	Accrued Environmental Loss Contingencies Noncurrent AccruedEnvironmentalLossContingenciesNoncurrent	6468000	USD
CY2020Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	30673000	USD
CY2019Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	30569000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	9872000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	9896000	USD
CY2020Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	4903000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	2796000	USD
CY2020Q4	us-gaap	Deferred Credits And Other Liabilities DeferredCreditsAndOtherLiabilities	397871000	USD
CY2019Q4	us-gaap	Deferred Credits And Other Liabilities DeferredCreditsAndOtherLiabilities	358129000	USD
CY2020Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1932487000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1783198000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	65153000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	56580000	USD
CY2020	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	58117000	USD
CY2019	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	45900000	USD
CY2018	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	40802000	USD
CY2020	cpk	Depreciation And Accretion Included In Other Costs DepreciationAndAccretionIncludedInOtherCosts	9599000	USD
CY2019	cpk	Depreciation And Accretion Included In Other Costs DepreciationAndAccretionIncludedInOtherCosts	8752000	USD
CY2018	cpk	Depreciation And Accretion Included In Other Costs DepreciationAndAccretionIncludedInOtherCosts	8535000	USD
CY2020	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-24709000	USD
CY2019	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-24476000	USD
CY2018	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-21226000	USD
CY2020	cpk	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax Incremental DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTaxIncremental	200000	USD
CY2019	cpk	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax Incremental DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTaxIncremental	7344000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	6243000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	4135000	USD
CY2018	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-5497000	USD
CY2020	us-gaap	Unrealized Gain Loss On Commodity Contracts UnrealizedGainLossOnCommodityContracts	1482000	USD
CY2019	us-gaap	Unrealized Gain Loss On Commodity Contracts UnrealizedGainLossOnCommodityContracts	1595000	USD
CY2018	us-gaap	Unrealized Gain Loss On Commodity Contracts UnrealizedGainLossOnCommodityContracts	-429000	USD
CY2020	us-gaap	Employee Benefits And Share Based Compensation EmployeeBenefitsAndShareBasedCompensation	207000	USD
CY2019	us-gaap	Employee Benefits And Share Based Compensation EmployeeBenefitsAndShareBasedCompensation	1985000	USD
CY2018	us-gaap	Employee Benefits And Share Based Compensation EmployeeBenefitsAndShareBasedCompensation	856000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	4829000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	4279000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	2813000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	7426000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-36489000	USD
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	16311000	USD
CY2020	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-1709000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-8227000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-2107000	USD
CY2020	us-gaap	Increase Decrease In Regulatory Assets And Liabilities IncreaseDecreaseInRegulatoryAssetsAndLiabilities	4973000	USD
CY2019	us-gaap	Increase Decrease In Regulatory Assets And Liabilities IncreaseDecreaseInRegulatoryAssetsAndLiabilities	7812000	USD
CY2018	us-gaap	Increase Decrease In Regulatory Assets And Liabilities IncreaseDecreaseInRegulatoryAssetsAndLiabilities	-2250000	USD
CY2020	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-2424000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-11115000	USD
CY2018	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	7421000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	4941000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-62021000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	35907000	USD
CY2020	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-7165000	USD
CY2019	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	4750000	USD
CY2018	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	522000	USD
CY2020	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	2238000	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	-1811000	USD
CY2018	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	-596000	USD
CY2020	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	-2473000	USD
CY2019	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	2120000	USD
CY2018	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	708000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-5723000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-16064000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-35498000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	158916000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	102964000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	117362000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	165511000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	184727000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	240351000	USD
CY2020	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	8080000	USD
CY2020	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	22231000	USD
CY2019	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	23988000	USD
CY2019	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	427000	USD
CY2018	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	782000	USD
CY2018	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	16654000	USD
CY2020	cpk	Proceeds From Divestiture Of Businesses Incremental ProceedsFromDivestitureOfBusinessesIncremental	200000	USD
CY2019	cpk	Proceeds From Divestiture Of Businesses Incremental ProceedsFromDivestitureOfBusinessesIncremental	22871000	USD
CY2020	cpk	Payments For Environmental Expenditures PaymentsForEnvironmentalExpenditures	2169000	USD
CY2019	cpk	Payments For Environmental Expenditures PaymentsForEnvironmentalExpenditures	1170000	USD
CY2018	cpk	Payments For Environmental Expenditures PaymentsForEnvironmentalExpenditures	625000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-181631000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-186587000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	22043000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-256848000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	27161000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	24693000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	22627000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	721000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	706000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	60980000	USD
CY2019	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
CY2020	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	977000	USD
CY2019	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	692000	USD
CY2018	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1210000	USD
CY2020	us-gaap	Increase Decrease In Outstanding Checks Financing Activities IncreaseDecreaseInOutstandingChecksFinancingActivities	-825000	USD
CY2019	us-gaap	Increase Decrease In Outstanding Checks Financing Activities IncreaseDecreaseInOutstandingChecksFinancingActivities	-1174000	USD
CY2018	us-gaap	Increase Decrease In Outstanding Checks Financing Activities IncreaseDecreaseInOutstandingChecksFinancingActivities	-5943000	USD
CY2020	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	-71637000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	5614000	USD
CY2019	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	-45913000	USD
CY2018	us-gaap	Proceeds From Repayments Of Lines Of Credit ProceedsFromRepaymentsOfLinesOfCredit	49432000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	89822000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	199648000	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	154819000	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	53600000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	41936000	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	34388000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	19229000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	84519000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	139961000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-3486000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	896000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	475000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	6985000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	6089000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	3499000	USD
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2019	us-gaap	Dividends Dividends	26191000	USD
CY2019	cpk	Stock Issued During The Period Value Retirement Savings Plan And Dividend Reinvestment Plan StockIssuedDuringThePeriodValueRetirementSavingsPlanAndDividendReinvestmentPlan	3000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	3618000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	6985000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	6089000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	486294000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	56580000	USD
CY2018	cpk	New Accounting Pronouncement Or Change In Accounting Principle Effect Of Adoption Quantification Principle Effect Of Adoption Quantification NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantificationPrincipleEffectOfAdoptionQuantification	-1498000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1534000	USD
CY2018	us-gaap	Dividends Dividends	23600000	USD
CY2018	cpk	Stock Issued During The Period Value Retirement Savings Plan And Dividend Reinvestment Plan StockIssuedDuringThePeriodValueRetirementSavingsPlanAndDividendReinvestmentPlan	3000	USD
CY2018	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	2200000	USD
CY2018	cpk	Treasury Stock Activity And Deferred Compensation Plan Activity During Period Value TreasuryStockActivityAndDeferredCompensationPlanActivityDuringPeriodValue	0	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	518439000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	65153000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	561000	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	3893000	USD
CY2020	cpk	New Accounting Pronouncement Or Change In Accounting Principle Effect Of Adoption Quantification Principle Effect Of Adoption Quantification NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantificationPrincipleEffectOfAdoptionQuantification	-30000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	697085000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	561577000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3402000	USD
CY2020	us-gaap	Dividends Dividends	29106000	USD
CY2020	cpk	Stock Issued Value During The Period Shares Retirement Savings Plan And Dividend Reinvestment Plan StockIssuedValueDuringThePeriodSharesRetirementSavingsPlanAndDividendReinvestmentPlan	85851000	USD
CY2020Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2020Q4	cpk	Shares Held In Trust For Deferred Compensation Plan SharesHeldInTrustForDeferredCompensationPlan	105087	shares
CY2019Q4	cpk	Shares Held In Trust For Deferred Compensation Plan SharesHeldInTrustForDeferredCompensationPlan	95329	shares
CY2018Q4	cpk	Shares Held In Trust For Deferred Compensation Plan SharesHeldInTrustForDeferredCompensationPlan	97053	shares
CY2020	cpk	Shares Issued Under Performance Incentive Plan Withheld For Employee Taxes SharesIssuedUnderPerformanceIncentivePlanWithheldForEmployeeTaxes	10319	shares
CY2019	cpk	Shares Issued Under Performance Incentive Plan Withheld For Employee Taxes SharesIssuedUnderPerformanceIncentivePlanWithheldForEmployeeTaxes	7635	shares
CY2018	cpk	Shares Issued Under Performance Incentive Plan Withheld For Employee Taxes SharesIssuedUnderPerformanceIncentivePlanWithheldForEmployeeTaxes	16918	shares
CY2020	us-gaap	Use Of Estimates UseOfEstimates	Use of EstimatesThe preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates in measuring assets and liabilities and related revenues and expenses. These estimates involve judgments about various future economic factors that are difficult to predict and are beyond our control; therefore, actual results could differ from these estimates. As additional information becomes available, or actual amounts are determined, recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1908992000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1746532000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	368743000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	336876000	USD
CY2020Q4	cpk	Construction Work In Progress ConstructionWorkInProgress	60929000	USD
CY2019Q4	cpk	Construction Work In Progress ConstructionWorkInProgress	54141000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1601178000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1463797000	USD
CY2020Q4	us-gaap	Contributions In Aid Of Construction ContributionsInAidOfConstruction	2900000	USD
CY2019Q4	us-gaap	Contributions In Aid Of Construction ContributionsInAidOfConstruction	2100000	USD
CY2020	us-gaap	Public Utilities Allowance For Funds Used During Construction Additions PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions	700000	USD
CY2019	us-gaap	Public Utilities Allowance For Funds Used During Construction Additions PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions	700000	USD
CY2018	us-gaap	Public Utilities Allowance For Funds Used During Construction Additions PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions	1900000	USD
CY2020	cpk	Numberof Monthsto Establish Rou Assetand Liability NumberofMonthstoEstablishROUAssetandLiability	P12M
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	9600000	USD
CY2019	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	8800000	USD
CY2018	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	8500000	USD
CY2020	cpk	Delayof Revenue Recognition Due To Implementationof New Standard DelayofRevenueRecognitionDueToImplementationofNewStandard	2	utility
CY2020	cpk	Lengthoftimeuntildeferredamountsrecoveredorrefunded Lengthoftimeuntildeferredamountsrecoveredorrefunded	1
CY2020	cpk	Maturity Period To Be Considered Cash Equivalents MaturityPeriodToBeConsideredCashEquivalents	P3M
CY2019Q4	cpk	Accounts Receivable Allowance For Credit Losses Current Disclosure AccountsReceivableAllowanceForCreditLossesCurrentDisclosure	1337000	USD
CY2020	us-gaap	Provision For Other Credit Losses ProvisionForOtherCreditLosses	3827000	USD
CY2020	us-gaap	Allowance For Doubtful Accounts Receivable Recoveries AllowanceForDoubtfulAccountsReceivableRecoveries	613000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	992000	USD
CY2020Q4	cpk	Accounts Receivable Allowance For Credit Losses Current Disclosure AccountsReceivableAllowanceForCreditLossesCurrentDisclosure	4785000	USD
CY2020	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	70642000	USD
CY2019	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	61100000	USD
CY2018	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	56968000	USD
CY2020	cpk	Discontinued Operation Gain Losson Disposalof Discontinued Operation Netof Lossfrom Discontinued Operations Netof Tax DiscontinuedOperationGainLossonDisposalofDiscontinuedOperationNetofLossfromDiscontinuedOperationsNetofTax	856000	USD
CY2019	cpk	Discontinued Operation Gain Losson Disposalof Discontinued Operation Netof Lossfrom Discontinued Operations Netof Tax DiscontinuedOperationGainLossonDisposalofDiscontinuedOperationNetofLossfromDiscontinuedOperationsNetofTax	4053000	USD
CY2018	cpk	Discontinued Operation Gain Losson Disposalof Discontinued Operation Netof Lossfrom Discontinued Operations Netof Tax DiscontinuedOperationGainLossonDisposalofDiscontinuedOperationNetofLossfromDiscontinuedOperationsNetofTax	-388000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	65153000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	56580000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16711579	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16398443	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16369616	shares
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	4.23
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	3.73
CY2018	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	3.48
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.05
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.24
CY2018	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.02
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16369616	shares
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	59156	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16711579	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16398443	shares
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.28
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.97
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.46
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	50043	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	50254	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16770735	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16448486	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16419870	shares
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	4.21
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	3.72
CY2018	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	3.47
CY2020	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	0.05
CY2019	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	0.24
CY2018	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	-0.02
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.26
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.96
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.45
CY2020	cpk	Number Of Disposal Transactions NumberOfDisposalTransactions	4	pure
CY2019	us-gaap	Proceeds From Divestiture Of Businesses ProceedsFromDivestitureOfBusinesses	23100000	USD
CY2019	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	5400000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	-204000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	-1578000	USD
CY2018	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	-223000	USD
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	809000	USD
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	-1875000	USD
CY2018	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	-517000	USD
CY2020	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	200000	USD
CY2019	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	7344000	USD
CY2018	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	0	USD
CY2020	cpk	Gain Loss From Discontinued Operations GainLossFromDiscontinuedOperations	856000	USD
CY2019	cpk	Gain Loss From Discontinued Operations GainLossFromDiscontinuedOperations	4053000	USD
CY2018	cpk	Gain Loss From Discontinued Operations GainLossFromDiscontinuedOperations	-388000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization	477000	USD
CY2018	us-gaap	Disposal Group Including Discontinued Operation Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization	582000	USD
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	488198000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	479605000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	490316000	USD
CY2019Q4	us-gaap	Receivables From Customers ReceivablesFromCustomers	47430000	USD
CY2019Q4	us-gaap	Contract With Customer Asset Net Noncurrent ContractWithCustomerAssetNetNoncurrent	3465000	USD
CY2019Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	589000	USD
CY2020Q4	us-gaap	Receivables From Customers ReceivablesFromCustomers	55600000	USD
CY2020Q4	us-gaap	Contract With Customer Asset Net Noncurrent ContractWithCustomerAssetNetNoncurrent	4816000	USD
CY2020Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	644000	USD
CY2020	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	8170000	USD
CY2020	us-gaap	Increase Decrease In Other Noncurrent Assets IncreaseDecreaseInOtherNoncurrentAssets	1351000	USD
CY2020	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	55000	USD
CY2020	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	1300000	USD
CY2019	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	1000000.0	USD
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	112723000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	106285000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	94844000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	3222000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-1847000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-607000	USD
CY2020	us-gaap	Interest Expense InterestExpense	21765000	USD
CY2019	us-gaap	Interest Expense InterestExpense	22224000	USD
CY2018	us-gaap	Interest Expense InterestExpense	16146000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	94180000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	82214000	USD
CY2020	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	70642000	USD
CY2019	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	61100000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	78091000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	23538000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21114000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21123000	USD
CY2018	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	56968000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	686000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1349000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-388000	USD
CY2020	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	170000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	3221000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	65153000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	56580000	USD
CY2019	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	5402000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	71498000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	58117000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	45424000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	40220000	USD
CY2020Q4	us-gaap	Assets Assets	1932487000	USD
CY2019Q4	us-gaap	Assets Assets	1783198000	USD
CY2020	us-gaap	Interest Paid InterestPaid	22884000	USD
CY2019	us-gaap	Interest Paid InterestPaid	23856000	USD
CY2018	us-gaap	Interest Paid InterestPaid	16741000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-8135000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	477000	USD
CY2020	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	23625000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	13470000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	39402000	USD
CY2020	cpk	Non Cash Performance Incentive Plan Retirement NonCashPerformanceIncentivePlanRetirement	1605000	USD
CY2020	cpk	Non Cash Performance Incentive Plan Expenses NonCashPerformanceIncentivePlanExpenses	1971000	USD
CY2019	cpk	Non Cash Performance Incentive Plan Expenses NonCashPerformanceIncentivePlanExpenses	1691000	USD
CY2018	cpk	Non Cash Performance Incentive Plan Expenses NonCashPerformanceIncentivePlanExpenses	2006000	USD
CY2020	us-gaap	Capital Lease Obligations Incurred CapitalLeaseObligationsIncurred	0	USD
CY2019	us-gaap	Capital Lease Obligations Incurred CapitalLeaseObligationsIncurred	0	USD
CY2018	us-gaap	Capital Lease Obligations Incurred CapitalLeaseObligationsIncurred	1310000	USD
CY2020	us-gaap	Notional Amount Of Nonderivative Instruments NotionalAmountOfNonderivativeInstruments	100000000.0	USD
CY2020	cpk	Number Of Short Term Lines Of Credit Rate Swap NumberOfShortTermLinesOfCreditRateSwap	3	pure
CY2020Q4	us-gaap	Notional Amount Of Nonderivative Instruments NotionalAmountOfNonderivativeInstruments	60000000.0	USD
CY2020Q4	us-gaap	Energy Marketing Contracts Assets Current EnergyMarketingContractsAssetsCurrent	3269000	USD
CY2019Q4	us-gaap	Energy Marketing Contracts Assets Current EnergyMarketingContractsAssetsCurrent	0	USD
CY2020Q4	us-gaap	Energy Marketing Contract Liabilities Current EnergyMarketingContractLiabilitiesCurrent	127000	USD
CY2019Q4	us-gaap	Energy Marketing Contract Liabilities Current EnergyMarketingContractLiabilitiesCurrent	1844000	USD
CY2020	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	7505000	USD
CY2019	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	910000	USD
CY2018	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-2701000	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	803000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	686000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases Sales Issuances Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	261000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases Sales Issuances Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	131000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Net FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet	1065000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Net FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet	-29000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	27000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	15000	USD
CY2020Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	2156000	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	803000	USD
CY2020Q4	us-gaap	Long Term Debt LongTermDebt	523000000.0	USD
CY2020Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	548500000	USD
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	486600000	USD
CY2019Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	505000000.0	USD
CY2020Q4	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	10776000	USD
CY2019Q4	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	9229000	USD
CY2020	us-gaap	Trading Securities Unrealized Holding Gain Loss TradingSecuritiesUnrealizedHoldingGainLoss	1500000	USD
CY2019	us-gaap	Trading Securities Unrealized Holding Gain Loss TradingSecuritiesUnrealizedHoldingGainLoss	1600000	USD
CY2018	us-gaap	Trading Securities Unrealized Holding Gain Loss TradingSecuritiesUnrealizedHoldingGainLoss	-400000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	32668000	USD
CY2020	us-gaap	Goodwill Transfers GoodwillTransfers	6063000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	38731000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	13777000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	5485000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	12365000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	4236000	USD
CY2020	us-gaap	Acquired Finite Lived Intangible Assets Weighted Average Useful Life AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife	P11Y
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1200000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	800000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	400000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	1300000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	1000000.0	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	900000	USD
CY2019Q4	cpk	Net Operating Losses And Tax Carryforwards NetOperatingLossesAndTaxCarryforwards	6300000	USD
CY2018Q4	cpk	Net Operating Losses And Tax Carryforwards NetOperatingLossesAndTaxCarryforwards	-12200000	USD
CY2020Q4	cpk	Deferred Tax Assets Operating Loss Carryforwards Total DeferredTaxAssetsOperatingLossCarryforwardsTotal	1600000	USD
CY2019Q4	cpk	Deferred Tax Assets Operating Loss Carryforwards Total DeferredTaxAssetsOperatingLossCarryforwardsTotal	5500000	USD
CY2020Q4	cpk	Net Operating Losses And Tax Carryback Total NetOperatingLossesAndTaxCarrybackTotal	-1800000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-2777000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-2252000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-361000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	2162000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-491000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	617000	USD
CY2020	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	-47000	USD
CY2019	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	-47000	USD
CY2018	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	-47000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-662000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-2790000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	209000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	24200000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	23904000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	20914000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	23538000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21114000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21123000	USD
CY2020	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Disposal Of Discontinued Operation DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperation	153000	USD
CY2019	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Disposal Of Discontinued Operation DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperation	1416000	USD
CY2018	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Disposal Of Discontinued Operation DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperation	-129000	USD
CY2020	us-gaap	Income Tax Expense Benefit Continuing Operations Discontinued Operations Extraordinary Items IncomeTaxExpenseBenefitContinuingOperationsDiscontinuedOperationsExtraordinaryItems	23691000	USD
CY2019	us-gaap	Income Tax Expense Benefit Continuing Operations Discontinued Operations Extraordinary Items IncomeTaxExpenseBenefitContinuingOperationsDiscontinuedOperationsExtraordinaryItems	22530000	USD
CY2018	us-gaap	Income Tax Expense Benefit Continuing Operations Discontinued Operations Extraordinary Items IncomeTaxExpenseBenefitContinuingOperationsDiscontinuedOperationsExtraordinaryItems	20994000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4900000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4700000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	3500000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	19778000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	17264000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	16400000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	5051000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	5093000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4071000	USD
CY2020Q4	cpk	Deferred Income Tax On Acquisition Adjustment DeferredIncomeTaxOnAcquisitionAdjustment	6618000	USD
CY2020	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	218000	USD
CY2019	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	173000	USD
CY2018	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	158000	USD
CY2020Q4	cpk	Net Operating Losses And Tax Carryback NetOperatingLossesAndTaxCarryback	-1841000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	768000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-1070000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	810000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	23538000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21114000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21123000	USD
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.2499
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.2565
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.2713
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	199287000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	173466000	USD
CY2019Q4	cpk	Deferred Income Tax On Acquisition Adjustment DeferredIncomeTaxOnAcquisitionAdjustment	6969000	USD
CY2020Q4	cpk	Deferred Tax Liabilities Loss On Reacquired Debt DeferredTaxLiabilitiesLossOnReacquiredDebt	201000	USD
CY2019Q4	cpk	Deferred Tax Liabilities Loss On Reacquired Debt DeferredTaxLiabilitiesLossOnReacquiredDebt	220000	USD
CY2020Q4	cpk	Deferred Income Tax Liability Deferred Gas Costs DeferredIncomeTaxLiabilityDeferredGasCosts	509000	USD
CY2019Q4	cpk	Deferred Income Tax Liability Deferred Gas Costs DeferredIncomeTaxLiabilityDeferredGasCosts	1223000	USD
CY2020Q4	cpk	Deferred Income Tax Liability Natural Gas Conversion Costs DeferredIncomeTaxLiabilityNaturalGasConversionCosts	5379000	USD
CY2019Q4	cpk	Deferred Income Tax Liability Natural Gas Conversion Costs DeferredIncomeTaxLiabilityNaturalGasConversionCosts	4956000	USD
CY2020Q4	cpk	Deferred Income Tax Liability Storm Reserve DeferredIncomeTaxLiabilityStormReserve	7073000	USD
CY2019Q4	cpk	Deferred Income Tax Liability Storm Reserve DeferredIncomeTaxLiabilityStormReserve	10316000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	5587000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	1456000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	224654000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	198606000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	4636000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	3818000	USD
CY2020Q4	cpk	Deferred Tax Assets Environmental DeferredTaxAssetsEnvironmental	1064000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	6153000	USD
CY2019Q4	cpk	Deferred Tax Assets Environmental DeferredTaxAssetsEnvironmental	1486000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	1587000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	5523000	USD
CY2020Q4	cpk	Deferred Tax Asset Self Insurance Accruals DeferredTaxAssetSelfInsuranceAccruals	0	USD
CY2019Q4	cpk	Deferred Tax Asset Self Insurance Accruals DeferredTaxAssetSelfInsuranceAccruals	146000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	409000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	96000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	2064000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	5417000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	4817000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	19266000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	17950000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	205388000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	180656000	USD
CY2020Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	901000	USD
CY2019Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	822000	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	522099000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	485768000	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	13600000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	45600000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	508499000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	440168000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Rolling Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextRollingTwelveMonths	13600000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Rolling Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInRollingYearTwo	17100000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Rolling Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInRollingYearThree	20600000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Rolling Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInRollingYearFour	17600000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Rolling Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInRollingYearFive	24600000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Rolling After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInRollingAfterYearFive	429500000	USD
CY2020Q4	cpk	Total Future Repayments TotalFutureRepayments	523000000	USD
CY2020Q4	us-gaap	Debt Instrument Unused Borrowing Capacity Amount DebtInstrumentUnusedBorrowingCapacityAmount	310000000	USD
CY2020Q4	cpk	Common Stock Equity To Total Capitalization CommonStockEquityToTotalCapitalization	0.400
CY2020Q4	cpk	Required Fixed Charge Coverage Ratio RequiredFixedChargeCoverageRatio	1.2
CY2020Q4	cpk	Debt Instrument Restrictive Covenants Required Net Book Valueof Regulated Business Assets Percentageof Consolidated Total Assets DebtInstrumentRestrictiveCovenantsRequiredNetBookValueofRegulatedBusinessAssetsPercentageofConsolidatedTotalAssets	0.500
CY2020	cpk	Longterm Debt Debt Covenants Maximum Allowable Amountof Restricted Payments LongtermDebtDebtCovenantsMaximumAllowableAmountofRestrictedPayments	10000000.0	USD
CY2020Q4	cpk	Cumulative Consolidated Net Income CumulativeConsolidatedNetIncome	581000000.0	USD
CY2020Q4	cpk	Restricted Payment RestrictedPayment	256400000	USD
CY2020Q4	cpk	Unrestricted Payment UnrestrictedPayment	324600000	USD
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	175600000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	247400000	USD
CY2020Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0128
CY2019Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0262
CY2020Q4	us-gaap	Notional Amount Of Nonderivative Instruments NotionalAmountOfNonderivativeInstruments	60000000.0	USD
CY2020Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	375000000.0	USD
CY2020Q4	us-gaap	Ratio Of Indebtedness To Net Capital1 RatioOfIndebtednessToNetCapital1	0.65
CY2020	us-gaap	Line Of Credit Facility Commitment Fee Percentage LineOfCreditFacilityCommitmentFeePercentage	0.00175
CY2020	us-gaap	Line Of Credit Facility Interest Rate During Period LineOfCreditFacilityInterestRateDuringPeriod	0.01125
CY2020Q4	us-gaap	Line Of Credit Facility Remaining Borrowing Capacity LineOfCreditFacilityRemainingBorrowingCapacity	196900000	USD
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	4800000	USD
CY2020	us-gaap	Notional Amount Of Nonderivative Instruments NotionalAmountOfNonderivativeInstruments	100000000.0	USD
CY2020	cpk	Number Of Short Term Lines Of Credit Rate Swap NumberOfShortTermLinesOfCreditRateSwap	3	pure
CY2020Q4	us-gaap	Notional Amount Of Nonderivative Instruments NotionalAmountOfNonderivativeInstruments	60000000.0	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	2029000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	2577000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	650000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	5000	USD
CY2020	us-gaap	Lease Cost LeaseCost	2029000	USD
CY2019	us-gaap	Lease Cost LeaseCost	3232000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11194000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11563000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	1747000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	1705000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	9872000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	9896000	USD
CY2020Q4	cpk	Total Operatingand Finance Lease Liabilities TotalOperatingandFinanceLeaseLiabilities	11619000	USD
CY2019Q4	cpk	Total Operatingand Finance Lease Liabilities TotalOperatingandFinanceLeaseLiabilities	11601000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y8M12D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y10M17D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.038
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.038
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	1956000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	2230000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	5000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	650000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	2027000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	1984000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1923000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1657000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	1395000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	4419000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	13405000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	1786000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	11619000	USD
CY2020Q4	cpk	Lessee Future Operating Lease Option Payments LesseeFutureOperatingLeaseOptionPayments	2100000	USD
CY2020Q4	cpk	Common Stock Shares Issued At The Market CommonStockSharesIssuedAtTheMarket	700000	shares
CY2020Q4	cpk	Shares Issued Price Per Share At The Market SharesIssuedPricePerShareAtTheMarket	82.93
CY2020	cpk	Proceeds From Issuance Of Common Stock At The Market ProceedsFromIssuanceOfCommonStockAtTheMarket	61000000.0	USD
CY2020	cpk	Fees On Equity Issuance At The Market FeesOnEquityIssuanceAtTheMarket	1500000	USD
	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	300000	shares
	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	86.12	USD
	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	22000000.0	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-6713000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	1289000	USD
CY2020	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	63000	USD
CY2019	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	728000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	561000	USD
CY2019	us-gaap	Tax Cuts And Jobs Act Of2017 Reclassification From Aoci To Retained Earnings Tax Effect TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect	-115000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-6267000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	4838000	USD
CY2020	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	1436000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	3402000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-2865000	USD
CY2020Q4	cpk	Numberof Plans NumberofPlans	3	plan
CY2020	cpk	Deferred Pension Settlement Expense DeferredPensionSettlementExpense	700000	USD
CY2019Q4	cpk	Numberof Sub Plans NumberofSubPlans	2
CY2019	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	74000	USD
CY2018	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	83000	USD
CY2020	cpk	Deferred Pension Settlement Expense DeferredPensionSettlementExpense	700000	USD
CY2020Q4	cpk	Defined Benefit Plan Alternative Investments Fair Valueof Plan Assets DefinedBenefitPlanAlternativeInvestmentsFairValueofPlanAssets	8116000	USD
CY2019Q4	cpk	Defined Benefit Plan Alternative Investments Fair Valueof Plan Assets DefinedBenefitPlanAlternativeInvestmentsFairValueofPlanAssets	7017000	USD
CY2020	cpk	Expected Amortization Of Pre Merger Regulatory Asset ExpectedAmortizationOfPreMergerRegulatoryAsset	0	USD
CY2020	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	-370000	USD
CY2020	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Loss Net Gain Loss Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax	-24326000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	23956000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	-6907000	USD
CY2020Q4	cpk	Defined Benefit Plan Post Merger Regulatory Assets DefinedBenefitPlanPostMergerRegulatoryAssets	17049000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	23956000	USD
CY2020Q4	cpk	Accumulated Other Comprehensive Income Loss Tax Effect AccumulatedOtherComprehensiveIncomeLossTaxEffect	1800000	USD
CY2020	cpk	Defined Contribution Plan Eligibility Threshold Requisite Service Period DefinedContributionPlanEligibilityThresholdRequisiteServicePeriod	P3M
CY2020	cpk	Defined Contribution Plan Maximum Employer Contribution As Percentage Of Eligible Compensation DefinedContributionPlanMaximumEmployerContributionAsPercentageOfEligibleCompensation	1
CY2020	us-gaap	Defined Contribution Plan Employers Matching Contribution Annual Vesting Percentage DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage	1
CY2020	us-gaap	Deferred Compensation Arrangement With Individual Requisite Service Period1 DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1	P2Y
CY2020	cpk	Employee Minimum Age To Participate Under Defined Contribution Plan EmployeeMinimumAgeToParticipateUnderDefinedContributionPlan	P55Y
CY2020Q4	cpk	Deferrals Rates After Deferral Period Ends Minimum DeferralsRatesAfterDeferralPeriodEndsMinimum	0.01
CY2020	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	5900000	USD
CY2019	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	5700000	USD
CY2018	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	5500000	USD
CY2020Q4	us-gaap	Common Stock Capital Shares Reserved For Future Issuance CommonStockCapitalSharesReservedForFutureIssuance	813230	shares
CY2020	cpk	Employee Deferral Rate EmployeeDeferralRate	0.80
CY2020	cpk	Deferred Compensation Employer Matching Contribution Rate DeferredCompensationEmployerMatchingContributionRate	0.06
CY2019Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-610000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	1117000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	4829000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	4279000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3410000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	1254000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	934000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	3575000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	3162000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	2476000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	751	shares
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	887	shares
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Additional Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized	43032	shares
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions	3900000	USD
CY2020	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	10319	shares
CY2019	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	7635	shares
CY2018	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	16918	shares
CY2020	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	977000	USD
CY2019	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	692000	USD
CY2018	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1210000	USD
CY2020	cpk	Regulatory Asset Storm Cost Recovery RegulatoryAssetStormCostRecovery	45800000	USD
CY2020	cpk	Surcharge Storm Cost Recovery SurchargeStormCostRecovery	7700000	USD
CY2020	cpk	Incremental Revenue Storm Cost Recovery IncrementalRevenueStormCostRecovery	3300000	USD
CY2020Q4	us-gaap	Regulatory Assets RegulatoryAssets	124592000	USD
CY2019Q4	us-gaap	Regulatory Assets RegulatoryAssets	78551000	USD
CY2020Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	149020000	USD
CY2019Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	133735000	USD
CY2020	cpk	Companys Exposure In Number Of Former Manufactured Gas Plant Sites CompanysExposureInNumberOfFormerManufacturedGasPlantSites	7	site
CY2020Q4	cpk	Debt Service Coverage Ratio DebtServiceCoverageRatio	1.25
CY2020	cpk	Ratiobasedonaveragenumberofpriorquarters Ratiobasedonaveragenumberofpriorquarters	6
CY2020Q4	cpk	Minimum Interest Coverage Ratio Under Agreement Two MinimumInterestCoverageRatioUnderAgreementTwo	2
CY2020Q4	cpk	Maximum Debt To Net Capital Ratio Under Agreement Two MaximumDebtToNetCapitalRatioUnderAgreementTwo	65
CY2020	cpk	Number Of Yearsto Collect Benefits NumberOfYearstoCollectBenefits	P20Y
CY2020	cpk	Number Of Yearsto Collect Benefits NumberOfYearstoCollectBenefits	P20Y
CY2020Q4	us-gaap	Purchase Obligation Due In Next Twelve Months PurchaseObligationDueInNextTwelveMonths	69459000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Second And Third Year PurchaseObligationDueInSecondAndThirdYear	81841000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Fourth And Fifth Year PurchaseObligationDueInFourthAndFifthYear	69420000	USD
CY2020Q4	us-gaap	Purchase Obligation Due After Fifth Year PurchaseObligationDueAfterFifthYear	201504000	USD
CY2020Q4	us-gaap	Purchase Obligation PurchaseObligation	422224000	USD
CY2020Q4	us-gaap	Guarantee Obligations Maximum Exposure GuaranteeObligationsMaximumExposure	20000000.0	USD
CY2020Q4	us-gaap	Guarantee Obligations Current Carrying Value GuaranteeObligationsCurrentCarryingValue	5700000	USD
CY2020	cpk	Standby Letters Of Credit StandbyLettersOfCredit	4800000	USD
CY2020Q1	us-gaap	Revenues Revenues	152690000	USD
CY2020Q2	us-gaap	Revenues Revenues	97051000	USD
CY2020Q3	us-gaap	Revenues Revenues	101419000	USD
CY2020Q4	us-gaap	Revenues Revenues	137038000	USD
CY2020Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	42134000	USD
CY2020Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	17977000	USD
CY2020Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	17406000	USD
CY2020Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	35206000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	29041000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	10661000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	9280000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	21661000	USD
CY2020Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-111000	USD
CY2020Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	125000	USD
CY2020Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-19000	USD
CY2020Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	691000	USD
CY2020	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	170000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	28930000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	10956000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	9261000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	22352000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.77
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.65
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.56
CY2020Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.24
CY2020Q1	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.01
CY2020Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.02
CY2020Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2020Q4	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.04
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.76
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.67
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.56
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.28
CY2020Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.77
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.64
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.56
CY2020Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.24
CY2020Q1	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	-0.01
CY2020Q2	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	0.02
CY2020Q3	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2020Q4	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	0.04
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.76
CY2019Q3	us-gaap	Revenues Revenues	92626000	USD
CY2019Q2	us-gaap	Revenues Revenues	94542000	USD
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.66
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.56
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.28
CY2019Q1	us-gaap	Revenues Revenues	160464000	USD
CY2019Q4	us-gaap	Revenues Revenues	131974000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	44122000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	18165000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	14357000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	29641000	USD
CY2019Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	28811000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	8914000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	6251000	USD
CY2019Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	17123000	USD
CY2019Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-148000	USD
CY2019Q1	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.01
CY2019Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.03
CY2019Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.04
CY2019Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-630000	USD
CY2019Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	39000	USD
CY2019Q4	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	5402000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	28663000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	8304000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	5621000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	22564000	USD
CY2019Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.76
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.54
CY2019Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.38
CY2019Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.05
CY2019Q4	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.33
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.75
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.51
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.34
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.38
CY2019Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.75
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.54
CY2019Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.38
CY2019Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.04
CY2019Q1	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	-0.01
CY2019Q2	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	-0.04
CY2019Q3	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	-0.04
CY2019Q4	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTaxPerDilutedShare	0.33
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.74
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.34
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.37
CY2019Q4	cpk	Accounts Receivable Allowance For Credit Losses Current Disclosure AccountsReceivableAllowanceForCreditLossesCurrentDisclosure	1337000	USD
CY2020	us-gaap	Provision For Other Credit Losses ProvisionForOtherCreditLosses	3827000	USD
CY2020	us-gaap	Allowance For Doubtful Accounts Receivable Recoveries AllowanceForDoubtfulAccountsReceivableRecoveries	613000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	992000	USD
CY2020Q4	cpk	Accounts Receivable Allowance For Credit Losses Current Disclosure AccountsReceivableAllowanceForCreditLossesCurrentDisclosure	4785000	USD
CY2018Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	1058000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1392000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	278000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1391000	USD
CY2019Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	1337000	USD
CY2017Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	876000	USD
CY2018	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1119000	USD
CY2018	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	133000	USD
CY2018	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1070000	USD
CY2018Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	1058000	USD

Files In Submission

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2020 Q4 Form 10-K Financial Statement

#000162828021003104 Filed on February 24, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CPK CHESAPEAKE UTILITIES CORP Stock $cpk

2020 Q4 Form 10-K Financial Statement

#000162828021003104 Filed on February 24, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CPK
CHESAPEAKE UTILITIES CORP Stock $cpk