XML 101 R85.htm IDEA: XBRL DOCUMENT
v3.25.3

Retirement Plans (Narrative) (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 28, 2025 USD ($) healthcarePlan | Sep. 28, 2025 USD ($) healthcarePlan benefitPlan | Sep. 29, 2024 USD ($) | Oct. 01, 2023 USD ($)
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Number of sponsored defined benefit pension plans | benefitPlan |  | 2 |  |
Lump sum payments from qualified plan | $ 14,400,000 |  |  |
Number of healthcare plans | healthcarePlan | 2 | 2 |  |
Cash flow period extension |  | 30 years |  |
Decrease in discount rate and expected return on plan assets (as a percent) |  | 0.0025 |  |
Decrease in earnings before income taxes from 0.25% decrease in the discount rate |  | $ 100,000 |  |
Decrease in earnings before income taxes from 0.25% decrease in the long-term rate of return on assets |  | 700,000 |  |
Minimum required contribution for retirement plans | $ 1,600,000 | 1,600,000 |  |
Qualified Defined Contribution Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined contribution plan, Company contributions |  | 3,400,000 | $ 3,300,000 | $ 2,300,000
Non-Qualified Deferred Compensation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined contribution plan, Company contributions |  | $ 100,000 | $ 200,000 | $ 100,000
Maximum annual contributions per employee, percent |  | 50.00% |  |
Maximum annual contributions per employee, percent of bonus |  | 85.00% |  |

X
- Definition Defined Benefit Plan, Assumptions Used in Calculation + References No definition available. + Details
Name: | jack_DefinedBenefitPlanAssumptionsUsedInCalculation
Namespace Prefix: | jack_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Decrease in Discount Rate On Earnings Before Income Taxes + References No definition available. + Details
Name: | jack_DefinedBenefitPlanDecreaseInDiscountRateOnEarningsBeforeIncomeTaxes
Namespace Prefix: | jack_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Impact of Decrease in Discount Rate on Earnings before Income Taxes + References No definition available. + Details
Name: | jack_DefinedBenefitPlanImpactOfDecreaseInDiscountRateOnEarningsBeforeIncomeTaxes
Namespace Prefix: | jack_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined Benefit Plan, Impact of Decrease in Long-term Rate of Return on Assets + References No definition available. + Details
Name: | jack_DefinedBenefitPlanImpactOfDecreaseInLongTermRateOfReturnOnAssets
Namespace Prefix: | jack_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Of Bonus + References No definition available. + Details
Name: | jack_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercentOfBonus
Namespace Prefix: | jack_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum required contribution for retirement plans + References No definition available. + Details
Name: | jack_MinimumRequiredContributionForRetirementPlans
Namespace Prefix: | jack_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number Of Defined Benefit Pension Plans Sponsored + References No definition available. + Details
Name: | jack_NumberOfDefinedBenefitPensionPlansSponsored
Namespace Prefix: | jack_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Healthcare Plans + References No definition available. + Details
Name: | jack_NumberOfHealthcarePlans
Namespace Prefix: | jack_
Data Type: | xbrli:integerItemType
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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (k) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (l) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (c)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-7 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (m) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(8) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanSettlementsPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480794/715-70-50-1 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=jack_QualifiedDefinedContributionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=jack_NonQualifiedDeferredCompensationPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |