Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)		3 Months Ended			6 Months Ended		12 Months Ended
	Jul. 30, 2014	Sep. 26, 2018	Jun. 27, 2018 USD ($) restaurant	Jun. 28, 2017 USD ($)	Jun. 27, 2018 USD ($) restaurant supplier segment	Jun. 28, 2017 USD ($)	Dec. 27, 2017 USD ($) supplier	Jul. 31, 2018	Jul. 30, 2018 USD ($)	Jul. 24, 2018	Jul. 21, 2018	Jul. 13, 2018 USD ($)	Jul. 02, 2018	Dec. 28, 2016 USD ($)	Dec. 11, 2014 USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | segment					1
Restricted dividend payments, description					Under the 2014 Revolver, Holdings may not make certain payments such as cash dividends, except that it may, inter alia, (i) pay up to $1.0 million per year to repurchase or redeem qualified equity interests of Holdings held by past or present officers, directors, or employees (or their estates) of the Company upon death, disability, or termination of employment, (ii) pay under its income tax receivable agreement (the “TRA”), and, (iii) so long as no default or event of default has occurred and is continuing, (a) make non-cash repurchases of equity interests in connection with the exercise of stock options by directors and officers, provided that those equity interests represent a portion of the consideration of the exercise price of those stock options, (b) pay up to $2.5 million per year pursuant to stock option plans, employment agreements, or incentive plans, (c) make up to $5.0 million in other restricted payments per year, and (d) make other restricted payments, subject to its compliance, on a pro forma basis, with (x) a lease-adjusted consolidated leverage ratio not to exceed 4.25 times and (y) the financial covenants applicable to the 2014 Revolver.
Total amount of outstanding debt			$ 86,300,000		$ 86,300,000
Cash available			13,085,000	$ 4,371,000	13,085,000	$ 4,371,000	$ 8,550,000							$ 2,168,000
Recovery of securities lawsuits related legal expenses			(2,429,000)	(511,000)	(4,063,000)	(511,000)
Operating lease obligations			282,300,000		282,300,000
Impairment of property and equipment			1,708,000	445,000	1,708,000	445,000
Property and equipment owned, net			103,937,000		103,937,000		102,794,000
Closed-store reserve expense			2,300,000		5,074,000	810,000
Unrecognized tax benefits, accrual of interest or penalties			0		0		0
Unrecognized tax benefits, interest or penalties expenses			0	0	$ 0	$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent					21.00%	35.00%
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)			712,000	(101,000)	$ (206,000)	$ 126,000
Deferred tax assets			6,713,000		6,713,000		7,167,000
Assets			448,648,000		448,648,000		442,711,000
Other accrued expenses and current liabilities			15,172,000		15,172,000		13,270,000
Liabilities, Current			50,622,000		50,622,000		47,325,000
Other noncurrent liabilities			21,278,000		21,278,000		12,772,000
Liabilities			168,520,000		168,520,000		167,761,000
Accumulated deficit			(94,340,000)		(94,340,000)		(98,427,000)
Stockholders' Equity Attributable to Parent			280,128,000		280,128,000		274,950,000
Liabilities and Equity			448,648,000		448,648,000		$ 442,711,000
Total revenue			111,633,000	105,573,000	217,389,000	205,344,000
Revenues			111,633,000		217,389,000
Franchise expenses			6,250,000	1,006,000	12,082,000	1,823,000
Costs and Expenses			104,044,000	92,833,000	205,352,000	183,243,000
Operating Income (Loss)			7,589,000	12,740,000	12,037,000	22,101,000
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			5,917,000	12,063,000	10,395,000	20,407,000
Net income			5,052,000	7,819,000	7,581,000	12,696,000
Calculated under revenue guidanec in effect before topic 606 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Deferred tax assets			5,428,000		5,428,000
Assets			447,363,000		447,363,000
Other accrued expenses and current liabilities			14,825,000		14,825,000
Liabilities, Current			50,275,000		50,275,000
Other noncurrent liabilities			16,914,000		16,914,000
Liabilities			163,809,000		163,809,000
Accumulated deficit			(90,914,000)		(90,914,000)
Stockholders' Equity Attributable to Parent			283,554,000		283,554,000
Liabilities and Equity			447,363,000		447,363,000
Revenues			106,236,000		206,907,000
Franchise expenses			797,000		1,532,000
Costs and Expenses			98,591,000		194,802,000
Operating Income (Loss)			7,645,000		12,105,000
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			5,973,000		10,463,000
Net income			5,108,000		7,649,000
Accounting Standards Update 2014-09
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Deferred tax assets			1,285,000		1,285,000
Assets			1,285,000		1,285,000
Other accrued expenses and current liabilities			347,000		347,000
Liabilities, Current			347,000		347,000
Other noncurrent liabilities			4,364,000		4,364,000
Liabilities			4,711,000		4,711,000
Accumulated deficit			(3,426,000)		(3,426,000)
Stockholders' Equity Attributable to Parent			(3,426,000)		(3,426,000)
Liabilities and Equity			1,285,000		1,285,000
Revenues			5,397,000		10,482,000
Franchise expenses			5,453,000		10,550,000
Costs and Expenses			5,453,000		10,550,000
Operating Income (Loss)			(56,000)		(68,000)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			(56,000)		(68,000)
Net income			(56,000)		(68,000)
Franchise revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total revenue			6,553,000	6,688,000	12,659,000	13,010,000
Franchise revenue | Calculated under revenue guidanec in effect before topic 606 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total revenue			6,609,000		12,727,000
Franchise revenue | Accounting Standards Update 2014-09
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total revenue			(56,000)		(68,000)
Franchise advertising fee revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total revenue			5,453,000	$ 0	10,550,000	$ 0
Franchise advertising fee revenue | Calculated under revenue guidanec in effect before topic 606 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total revenue			0		0
Franchise advertising fee revenue | Accounting Standards Update 2014-09
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Total revenue			5,453,000		10,550,000
Indefinite-lived Intangible Assets
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Asset impairment charges			$ 0		$ 0
Property, Plant and Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants			1	1	1	1
Supplier Concentration Risk
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of suppliers | supplier					0		1
Supplier Concentration Risk | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					10.00%
Supplier Concentration Risk | Supplier One [Member] | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration							14.00%
Supplier Concentration Risk | Largest Supplier One | Purchased
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			29.10%	33.00%	28.60%	32.00%
Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			100.00%		100.00%
Fair Value, Measurements, Nonrecurring [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Impairment of property and equipment				$ 387,000		$ 387,000
Property and equipment owned, net				302,000		302,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net				302,000		302,000
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Restrictive covenants, maximum annual repurchase or redemption of qualified entity interests					$ 1,000,000
Restrictive covenants, maximum annual payment for stock option plans, employment agreements and incentive plans					2,500,000
Restrictive covenants, maximum annual payment for other restricted payments					$ 5,000,000
Maximum leverage ratio					4.25
Covenant description, coverage ratio					1.75
Line of Credit Facility, Maximum Borrowing Capacity															$ 200,000,000
Debt Instrument, Maturity Date					Dec. 11, 2019
Debt Instrument, Periodic Payment			$ 5,000,000	$ 6,500,000	$ 13,000,000	$ 9,500,000
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility | Base Rate [Member] | Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate					0.75%
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility | Base Rate [Member] | Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate					1.50%
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate					1.75%
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate					2.50%
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility | Letter of Credit [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Line of Credit Facility, Current Borrowing Capacity															15,000,000
Credit Agreement Two Thousand Fourteen [Member] | Senior Secured Revolving Credit Facility | Swing Line Loans [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Line of Credit Facility, Current Borrowing Capacity															$ 15,000,000
TEXAS
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants Closed			2		4	1
Los Angeles [Member] | Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			68.50%	73.00%	68.80%	73.00%
ARIZONA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants Closed						1
Subsequent Event
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Authorized Amount									$ 20,000,000
Stock Repurchase Program Expiration Date		Jun. 26, 2019
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity												$ 150,000,000
Debt Instrument, Maturity Date		Jul. 13, 2023
Debt Instrument, Basis Spread on Variable Rate		1.00%
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility | Base Rate [Member] | Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.25%
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility | Base Rate [Member] | Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.25%
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility | Letter of Credit [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Line of Credit Facility, Current Borrowing Capacity												15,000,000
Subsequent Event | Credit Agreement Two Thousand Eighteen [Member] | Senior Secured Revolving Credit Facility | Swing Line Loans [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Line of Credit Facility, Current Borrowing Capacity												$ 15,000,000
Subsequent Event | Franchisees [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants										1			1
Subsequent Event | Company Operated Properties [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants											1
Subsequent Event | Company Operated Properties [Member] | ARIZONA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants								1
Entity Operated Units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant			211		211
Franchised Units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant			269		269