REVENUE - Narrative (Details) $ in Millions	6 Months Ended
Apr. 12, 2026 USD ($)
Revenue from Contract with Customer [Abstract]
Term of franchise	20 years
Development fees	$ 3.9

Contract With Customer, Liability, Development Fees For Unopened Stores

No definition available.

Name:	jack_ContractWithCustomerLiabilityDevelopmentFeesForUnopenedStores
Namespace Prefix:	jack_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant