XML 125 R105.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Employee Benefit Plans - Schedule of Asset Allocation Strategy (Detail) | Dec. 31, 2018
--- | ---
Minimum | Domestic Equities |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 14.00%
Minimum | Foreign Equities |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 13.00%
Minimum | Fixed Income |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 26.00%
Minimum | Alternative Strategies |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 6.00%
Minimum | Diversifying Assets |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 7.00%
Minimum | Cash |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 0.00%
Maximum | Domestic Equities |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 32.00%
Maximum | Foreign Equities |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 25.00%
Maximum | Fixed Income |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 40.00%
Maximum | Alternative Strategies |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 14.00%
Maximum | Diversifying Assets |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 19.00%
Maximum | Cash |
Debt and Equity Securities, FV-NI [Line Items] |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 5.00%

X
- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=cpk_DomesticEquitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=cpk_ForeignEquitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_FixedIncomeInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=cpk_AlternativeInvestmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=cpk_DiversifiedInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |