XML 120 R91.htm IDEA: XBRL DOCUMENT
v3.21.2

Savings and Deferred Compensation Plans Savings and Deferred Compensation Plans (Savings Plans) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Oct. 01, 2021 | Oct. 02, 2020 | Sep. 27, 2019
Savings And Deferred Compensation Plans [Abstract] |  |  |
Savings plans contributions | $ 132,865 | $ 91,833 | $ 114,006

X
- Definition Defined Contribution Plan Savings Plans Contributions + References No definition available. + Details
Name: | jec_DefinedContributionPlanSavingsPlansContributions
Namespace Prefix: | jec_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Savings And Deferred Compensation Plans [Abstract] + References No definition available. + Details
Name: | jec_SavingsAndDeferredCompensationPlansAbstract
Namespace Prefix: | jec_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration