Gift Card Liability and Loyalty Program Included in Accrued Expenses on Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Jul. 02, 2024	Jan. 02, 2024
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Gift card liability	$ 10,285	$ 14,380
Deferred loyalty revenue	$ 2,771	$ 2,510

Contract with customer liability for unredeeemed gift cards.

No definition available.

Name:	bjri_ContractWithCustomerLiabilityForUnredeeemedGiftCards
Namespace Prefix:	bjri_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant