BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) $ in Thousands, shares in Millions					1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 28, 2023 USD ($)	Dec. 28, 2022 USD ($)	Jul. 27, 2022 USD ($)	Jul. 30, 2014	Sep. 30, 2022 USD ($) restaurant	Sep. 27, 2023 USD ($) restaurant	Sep. 28, 2022 USD ($) restaurant	Sep. 27, 2023 USD ($) restaurant item segment	Sep. 28, 2022 USD ($) restaurant	Dec. 28, 2022 USD ($) item	Nov. 02, 2023 USD ($)	Oct. 31, 2023 shares
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total amount of outstanding debt						$ 80,000		$ 80,000
Cash available		$ 20,493				13,815		13,815		$ 20,493
Repayments of Lines of Credit								11,000	$ 20,000
Revolving line of credit		66,000				$ 80,000		$ 80,000		66,000
Number of reporting unit | item								1
Number of operating segments | segment								1
Restaurants sold | restaurant						17		18
Goodwill and intangible asset impairment						$ 0		$ 0
Goodwill decrement related to dispositions of restaurants								0		0
Closed-store reserve expense						100		100
Unrecognized tax benefits, accrual of interest or penalties		$ 0				0		0		$ 0
Gain on recovery of insurance proceeds, property, equipment and expenses								242
Gain on recovery of insurance proceeds, lost profits, net								(151)
Received from the insurance								400
Proceeds from disposition of restaurants						7,500		7,722
Gain on sale of restaurants						4,923		5,034
Unrecognized tax benefits, interest or penalties expenses						0	$ 0	0	0
Percentage of cash savings in taxes realized as a result of utilizing net operating losses payable to pre-IPO stockholders				85.00%
Income tax receivable agreement expense (income)						106	(29)	105	(345)
Asset impairment charges						1,000	100	1,000	400
(Gain) loss on disposal of assets						16	21	(34)	129
Provision for income taxes						$ 2,975	$ 1,776	$ 7,661	$ 5,736
Estimated effective tax rate						24.40%	26.20%	26.50%	28.70%
Statutory income tax rate								21.00%
Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Closed-store reserve expense							$ 100
Income tax receivable agreement expense (income)							$ (100)
Supplier Concentration Risk | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number Of Suppliers | item								0		1
Supplier Concentration Risk | Supplier One | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration		41.70%
Supplier Concentration Risk | Largest Supplier One | Purchased
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						26.60%	28.40%	27.00%	28.50%
Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						100.00%	100.00%	100.00%	100.00%
Subsequent Event
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of shares authorized to be repurchased | shares												20.0
Revolving Credit Facility | 2022 Credit Agreement
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Repayments of Lines of Credit						$ 3,000	$ 20,000	$ 11,000	$ 20,000
Revolving line of credit						80,000		80,000
Proceeds from Lines of Credit						$ 23,000		$ 25,000	$ 0
Maximum borrowing capacity			$ 150,000
Senior secured revolving facility term			5 years
Debt Instrument, Maturity Date								Jul. 27, 2027
Revolving Credit Facility | Subsequent Event | 2022 Credit Agreement
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Repayments of Lines of Credit	$ 9,000
Revolving line of credit											$ 71,000
California
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant						1		1
Number of restaurants with ROU asset impairment charges | restaurant							1		1
NEVADA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant						1		1
Greater Los Angeles area market | Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						71.60%	71.90%	71.10%	71.20%
Closed Store
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Closed-store reserve expense									$ 200
Fire
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					1
Fire | Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Incurred costs								$ 100
(Gain) loss on disposal of assets					$ 100
Company-operated
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant						171		171
Franchised
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant						321		321