Summary of Significant Accounting Policies - Additional Information (Details)					12 Months Ended
	Aug. 04, 2020 USD ($) item	Aug. 03, 2020 USD ($) item	Jul. 30, 2014	Jul. 11, 2014 restaurant	Dec. 29, 2021 USD ($) segment item restaurant	Dec. 30, 2020 USD ($) item restaurant	Dec. 29, 2020 USD ($)	Dec. 25, 2019 USD ($) restaurant item
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | segment					1
Restaurants sold | restaurant								4
Leaves of absence and overtime pay due to COVID 19					$ 3,900,000	$ 4,900,000
Employee retention credit					3,400,000
Bad debt expense					0	190,000		$ 0
Total amount of outstanding debt					40,000,000.0
Cash available					30,046,000	13,219,000
Gain on recovery of insurance proceeds					0	2,000,000		0
Proceeds from disposition of restaurants					4,556,000	0		4,770,000
Net loss on sale of restaurants					(1,534,000)	0		$ (5,058,000)
Number of restaurant sales | item								3
Impairment of property and equipment					711,000	3,498,000		$ 3,559,000
Number of restaurants closed | restaurant								1
Unrecognized tax benefits, accrual of interest or penalties					0	0
Interest related to NOPA					100,000
TRA tax expense (benefit)					100,000	100,000		$ (100,000)
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 (income) expense					$ 58,000	139,000		57,000
AMT Credits, CARES Act						400,000
Proceeds from Income Tax Refunds						500,000
Total deferred amount						4,900,000
Percentage of deferred amount due by current fiscal year					50.00%
Percentage of deferred amount due by next fiscal year					50.00%
Percentage of qualified wages paid for refundable payroll tax credit					70.00%
Employee retention credit					$ 2,400,000
Employee retention tax credit					3,400,000
Capitalized internal cost					1,400,000	1,000,000.0		1,100,000
Expense for payroll and benefits reserves					9,000,000.0	8,400,000		9,600,000
Promotional allowances amount					$ 7,700,000	7,500,000		8,000,000.0
Loyalty Rewards Program, Points Needed For One Reward | item	50	100
Loyalty Rewards Program, Award Earned	$ 5	$ 10
Loyalty Rewards Program, Expiration Period For Inactivity	1 year
Loyalty Reward Program, unused reward expiration period	6 months
Loyalty Rewards Program, Expected Loyalty Points Redemption Period					1 year
Accrued loyalty rewards program liability					$ 700,000	900,000
Advertising expense					16,100,000	15,300,000		16,100,000
Asset impairment charges					700,000	3,500,000		3,600,000
Operating Lease ROU assets					171,981,000	177,129,000
Accrued advertising					3,600,000	100,000
Insurance proceeds						100,000
Recovery of securities lawsuits related legal expenses and other insurance claims					0	(123,000)		(10,000,000)
Charge relating to present value of total expected TRA payments					1,500,000	3,100,000
Payments to pre-IPO stockholders under TRA					$ 1,658,000	5,237,000		5,764,000
Number of commitments to open franchised restaurants | restaurant					67
Amortization of deferred financing costs					$ 251,000	252,000		$ 251,000
Accounts payable					$ 10,626,000	7,472,000
Franchise Rights
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life					20 years
Finite-Lived Intangible Asset, Useful Life Renewal Period					20 years
Minimum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period					10 years
Percentage of monthly franchise fee					4.00%
Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period					20 years
Percentage of monthly franchise fee					5.00%
Other Assets
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Deferred financing fees net of accumulated amortization					$ 400,000	600,000
Franchise Development Initial Option Agreement | Limited Liability Company
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant				15
Number of years available under plan				5 years
Franchise Development Additional Option Agreement
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of years available under plan				10 years
Franchise Development Additional Option Agreement | Limited Liability Company
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant				100
Number of years available under plan				5 years
Franchise Development Agreement | Limited Liability Company
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Related party agreement, termination period				10 years
Closed Or Subleased Restaurant Locations
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Operating Lease ROU assets					$ 21,900,000	$ 27,700,000
Accounts Receivable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Franchisees | item					1
Supplier Concentration Risk | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number Of Suppliers | item					1	2
Supplier Concentration Risk | Supplier One | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					26.10%	24.20%
Supplier Concentration Risk | Supplier Two | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						11.40%
Supplier Concentration Risk | Largest Supplier One | Purchased
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					27.10%	26.90%		29.00%
Supplier Concentration Risk | Largest Supplier One | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accounts payable					$ 0	$ 0
Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					100.00%	100.00%		100.00%
Hardware Services
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Revenue, Remaining Performance Obligation, Amount					$ 0
Texas
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants with ROU asset impairment charges | restaurant						1		1
Number of restaurants closed | restaurant								2
Texas | Assets held for sale | Restaurant Sales
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants agreed to sell to a third party | restaurant								5
California
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					3			1
Number of restaurants with ROU asset impairment charges | restaurant					1	4		1
Restaurants sold | restaurant								4
Number of restaurants closed | restaurant								2
Greater Los Angeles area market | Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					70.90%	71.30%		70.50%
Sacramento Area | Assets held for sale | Restaurant Sales
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants agreed to sell to a third party | restaurant					8
San Francisco | Assets held for sale | Restaurant Sales
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants agreed to sell to a third party | restaurant								4
Phoenix | Assets held for sale | Restaurant Sales
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants agreed to sell to a third party | restaurant								7
Interest Expense
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Amortization of deferred financing costs					$ 300,000	$ 300,000		$ 300,000
General and Administrative Expense
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Preopening costs					300,000	100,000		400,000
General and Administrative Expense | Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Abandoned site and other site selection costs					100,000	100,000		100,000
Closed Store
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Closed-store reserve expense					$ 400,000		$ 1,200,000	1,300,000
Company-operated
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					189
Proceeds from disposition of restaurants								4,800,000
Net loss on sale of restaurants								5,100,000
Company-operated | Greater Los Angeles area market
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					141
Company-operated | Sacramento Area
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Proceeds from disposition of restaurants					$ 4,600,000
Net loss on sale of restaurants					$ 1,500,000
Franchised
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					291
Advertising fees					$ 25,900,000	$ 22,600,000		$ 22,400,000
Franchised | Accounts Receivable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Franchisees | item						1
Franchised | Geographic Concentration Risk | Accounts Receivable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					10.60%	11.50%
Franchised | Greater Los Angeles area market
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					135