XML 201 R59.htm IDEA: XBRL DOCUMENT
v3.20.2

Investments - Schedule of Investments (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Investments schedule [Line Items] |  |
Investments, at fair value | $ 9,680 | $ 9,229
Rabbi Trust Associated With Deferred Compensation Plan [Member] |  |
Investments schedule [Line Items] |  |
Investments, at fair value | 9,663 | 9,202
Equity Securities [Member] |  |
Investments schedule [Line Items] |  |
Investments, at fair value | $ 17 | $ 27

X
- Definition [Line Items] for Investments schedule [Table] + References No definition available. + Details
Name: | cpk_InvestmentsscheduleLineItems
Namespace Prefix: | cpk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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