XML 43 R87.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Employee Benefit Plans - Schedule of Assets by Investment Type (Detail) | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
--- | --- | --- | ---
Chesapeake Pension Plan [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 100.00% | 100.00% | 100.00%
Chesapeake Pension Plan [Member] | Investments in equity securities [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 52.07% | 51.75% | 64.33%
Chesapeake Pension Plan [Member] | Debt securities [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 38.00% | 37.88% | 30.60%
Chesapeake Pension Plan [Member] | Other [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 9.93% | 10.37% | 5.07%
FPU Pension Plan [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 100.00% | 100.00% | 100.00%
FPU Pension Plan [Member] | Investments in equity securities [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 52.81% | 51.98% | 60.00%
FPU Pension Plan [Member] | Debt securities [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 38.04% | 38.05% | 35.00%
FPU Pension Plan [Member] | Other [Member] |  |  |
Asset Category |  |  |
Percentage of assets by investment type | 9.15% | 9.97% | 5.00%

X
- Definition Defined Benefit Plan Percentage Of Plan Assets By Investment Type + References No definition available. + Details
Name: | cpk_DefinedBenefitPlanPercentageOfPlanAssetsByInvestmentType
Namespace Prefix: | cpk_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration