Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)		4 Months Ended	6 Months Ended		12 Months Ended
	Mar. 29, 2017 $ / shares shares	Jan. 03, 2017 location $ / shares	Dec. 29, 2015 USD ($)	Jun. 30, 2015 USD ($)	Jan. 01, 2019 USD ($) Segment renewal restaurant vendor $ / shares shares	Jan. 02, 2018 USD ($) $ / shares shares	Jan. 03, 2017 USD ($) $ / shares shares
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Franchise agreement, term					20 years
Document Period End Date					Jan. 01, 2019
Share Price | $ / shares		$ 3.31			$ 4.92	$ 4.63	$ 3.31
Number of vendors | vendor					1
Interest capitalized in connection with construction							$ 100,000
Lease agreement term (in years)					35 years
Deductible per occurrence for general liability					$ 350,000
Percentage of net sales for advertising					4.00%
Pre-opening costs						$ 1,591,000
Number of operating segments | Segment					1
Number of reportable segments | Segment					1
Entity operated units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					322
Franchised units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					258
CALIFORNIA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					376
CALIFORNIA | Entity operated units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					255
CALIFORNIA | Franchised units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant					121
Minimum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of lease renewal options | renewal					1
Lease renewal term (in years)					5 years
Insurance coverage deductibles range for claims					$ 250,000
Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of lease renewal options | renewal					4
Lease renewal term (in years)					10 years
Insurance coverage deductibles range for claims					$ 500,000
Capitalized software
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets (in years)					3 years
Buildings under capital leases
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets (in years)					20 years
Restaurant and other equipment | Minimum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets (in years)					3 years
Restaurant and other equipment | Maximum
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets (in years)					15 years
Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets					$ 3,861,000	0	0
Deferred income taxes					69,471,000	68,574,000
DeferredGiftCardIncomeTotal					2,800,000	2,500,000
Deferred gift card income					1,290,000	1,234,000
Allowance for doubtful accounts					100,000	100,000
Noncurrent portion of advanced reimbursements					700,000	1,100,000
Current portion of advanced reimbursements					400,000	434,000
Depreciation and amortization expense			$ 20,600,000		23,100,000	21,000,000
Property and equipment depreciation expense					69,089,000	49,888,000
Carrying value of capitalized software costs					2,300,000	2,100,000
Capitalized software costs					1,500,000	1,000,000
Capitalized software amortization expense			900,000	$ 400,000	1,200,000	1,000,000
Interest capitalized in connection with construction					123,000	131,000
Carrying value of unfavorable lease liabilities					19,200,000	20,600,000
Lease accumulated amortization					7,200,000	6,100,000
Number of underperforming locations | location		12
Amortization credits for unfavorable lease liabilities			2,600,000		$ 2,500,000	2,700,000
Weighted-average amortization period (in years)					7 years 3 months 18 days
Advertising expenses					$ 19,000,000	18,100,000	17,200,000
Pre-opening costs			700,000		1,584,000	1,591,000	731,000
Partnership monthly rental income				1,400,000
Proceeds from credit facility					31,000,000	31,500,000	24,000,000
Gift Card Liability, Current					1,500,000	1,300,000
Adjustment for adoption of new revenue recognition standard, net of tax						(707,000)
Successor | Entity operated units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accrued advertising					900,000	400,000
Successor | Franchised units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accrued advertising					700,000	300,000
Successor | Buildings under capital leases
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization expense			$ 1,400,000		900,000	1,200,000
Property and equipment depreciation expense					2,200,000	2,500,000
Successor | Construction-in-progress
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Capitalized construction costs				$ 1,300,000	1,600,000
Adjustments for Prior Revenue Recognition Standards | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Advertising expenses					13,300,000
Franchise revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Franchise revenue from amortization of deferred franchise fees as a result of the adoption of Topic 606					100,000
Gain on termination of development agreement					100,000
Deferred franchise fees					1,000,000
Franchise revenue | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Revenue					(17,569,000)	(16,464,000)	(15,676,000)
Franchise advertising contributions | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Revenue					$ (13,300,000)	$ 0	$ 0
Warrants | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Shares/warrants repurchased (in shares/warrants) | shares	400,000				47,511	424,439	699,007
Average cost per share/warrant (in dollars per share/warrant) | $ / shares	$ 3.75				$ 2.55	$ 3.72	$ 2.54
Discount on repurchase	5.00%
Share Price | $ / shares	$ 3.95
Retained Earnings (Accumulated Deficit) | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Adjustment for adoption of new revenue recognition standard, net of tax						$ (707,000)
Retained Earnings (Accumulated Deficit) | Franchise revenue | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Adjustment for adoption of new revenue recognition standard, net of tax						$ (700,000)
Accounting Standards Update 2014-09 | Adjustments for Prior Revenue Recognition Standards | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets					$ 0
Deferred income taxes					370,000
Pre-opening costs					0
Accounting Standards Update 2014-09 | Franchise revenue | Adjustments for Prior Revenue Recognition Standards | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Deferred income taxes					300,000
Revenue					370,000
Accounting Standards Update 2014-09 | Franchise advertising contributions | Adjustments for Prior Revenue Recognition Standards | Successor
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Revenue					$ 13,300,000