Summary of Significant Accounting Policies - Additional Information (Detail)				1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 24, 2014 USD ($) Restaurants	Jul. 30, 2014	Jul. 11, 2014 Restaurant	Nov. 30, 2015 Restaurants	Mar. 29, 2017 USD ($)	Dec. 28, 2016 USD ($) Restaurants Supplier	Dec. 30, 2015 USD ($) Restaurants Restaurant Supplier	Dec. 31, 2014 USD ($) Restaurant	Feb. 22, 2017 Restaurant	Feb. 17, 2017 USD ($)	Jan. 17, 2017 USD ($)	Dec. 29, 2016	Sep. 28, 2016 Restaurants	Jun. 29, 2016 Restaurants	Mar. 30, 2016 Restaurants	Sep. 30, 2015 Restaurants	Jul. 01, 2015 Restaurants	Apr. 01, 2015 Restaurants	Dec. 25, 2013 USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total amount of outstanding debt						$ 104,500,000
Cash available						2,168,000	$ 6,101,000	$ 11,499,000											$ 17,015,000
Expected closed-store reserve						154,000	(89,000)	740,000
Capitalized internal cost						1,600,000	1,100,000
Capitalized internal interest cost						200,000
Asset impairment charges						8,400,000	181,000	293,000
Number of restaurants | Restaurants	6
Amortization expense for deferred financing costs						304,000	304,000	1,302,000
Accrued insurance						5,444,000	5,021,000
Expense for payroll and benefits reserves						7,200,000	7,900,000	5,600,000
Promotional allowances amount						7,400,000	7,400,000	7,200,000
Initial franchise revenue						400,000	800,000	600,000
Advertising expense						14,700,000	13,900,000	13,500,000
Accrued advertising						0	204,000
Advertising cost included in accounts receivable and current assets						100,000	0
Number of restaurants damaged | Restaurants				1
Costs incurred directly related to fire						48,000
Disposition of assets related to fire						100,000	100,000
Gain on recovery of insurance proceeds, related to the reimbursement of property and equipment and expenses incurred						741,000
Gain on recovery of insurance proceeds, related to the reimbursement of lost profits						502,000
Amount received from insurance company in cash						1,400,000
Unrecognized tax benefits, accrual of interest or penalties						0	0
Unrecognized tax benefits, interest or penalties expenses						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%
Charge relating to present value of total expected TRA payments						38,700,000	41,400,000	41,400,000
Payments to pre-IPO stockholders under TRA						3,236,000
Write off of goodwill	$ 700,000
Operating lease obligations						$ 283,144,000
Initial Option [Member] | Limited Liability Company [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | Restaurant			15
Number of years available under plan			5 years
Additional Option [Member] | Limited Liability Company [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | Restaurant			100
Number of years available under plan			10 years
Franchise Development Agreement [Member] | Limited Liability Company [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Related party agreement, termination period			10 years
Related party agreement, termination description						The Franchise Development Option Agreement terminates (i) ten years after execution, or (ii) if the Initial Option is exercised, five years after that exercise.
Level 3 Measurements [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Write off of goodwill								700,000
Area Development Fees [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Unrecognized area development fees						$ 900,000	$ 900,000
Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of monthly franchise fee						4.00%
Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of monthly franchise fee						5.00%
Accrued advertising						$ 100,000
Costs incurred directly related to fire						$ 100,000
Franchised Units [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | Restaurants						259	247						253	251	248	245	244	243
Advertising fees						$ 19,300,000	$ 18,500,000	17,600,000
Interest Expense [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Amortization expense for deferred financing costs						300,000	300,000	1,300,000
General and Administrative Expense [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Preopening costs						2,600,000	1,500,000	1,200,000
Other Assets [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Deferred financing fees net of accumulated amortization						900,000	1,200,000
Other Current Liabilities [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Charge relating to present value of total expected TRA payments						12,400,000
Other Noncurrent Liabilities [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Charge relating to present value of total expected TRA payments						26,300,000
Indefinite-lived Intangible Assets [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Asset impairment charges						$ 0	$ 0	$ 0
Number of restaurants | Restaurants						9
Supplier Concentration Risk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of suppliers | Supplier						1	2
Supplier One [Member] | Accounts Payable [Member] | Supplier Concentration Risk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						16.00%
Supplier Two [Member] | Accounts Payable [Member] | Supplier Concentration Risk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration							12.00%
Supplier Three [Member] | Accounts Payable [Member] | Supplier Concentration Risk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration							11.00%
Largest Supplier One [Member] | Purchased [Member] | Supplier Concentration Risk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						33.00%	36.00%	36.00%
The Greater Los Angeles Area [Member] | Franchised Units [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | Restaurants						138
The Greater Los Angeles Area [Member] | Revenue [Member] | Geographic Concentration Risk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration						75.00%	79.00%	80.00%
Arizona, California and Texas [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | Restaurants						9
California [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | Restaurant							1	1
Scenario Forecast [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Expected closed-store reserve					$ 800,000
Subsequent Event [Member] | Texas [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurant closed | Restaurant									1
Subsequent Event [Member] | Arizona [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurant closed | Restaurant									1
Parent [Member] | Subsequent Event [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of new stores opened												5
Franchisees [Member] | Subsequent Event [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of new stores opened												3
Senior Secured Revolving Credit Facility [Member] | Subsequent Event [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Pre-payment for new restaurant										$ 1,500,000	$ 1,500,000
2013 First Lien Credit Agreement [Member] | Senior Secured Revolving Credit Facility [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Amount of borrowings available						$ 87,900,000													$ 7,700,000
2013 Credit Agreement [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Write off of unamortized deferred finance costs						$ 6,600,000