Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2016	Dec. 30, 2015	Dec. 31, 2014
Cash flows from operating activities
Net income	$ 18,339	$ 24,054	$ 42,463
Adjustments to reconcile changes in net income to net cash provided by operating activities:
Depreciation and amortization	16,053	13,092	11,538
Loss on early extinguishment of debt			9,718
Stock-based compensation expense	1,063	539	1,093
Interest accretion			290
Fire insurance proceeds for expenses paid and lost profit	611
Income tax receivable agreement expense	352	156	41,382
Gain on disposition of restaurants	(28)		(2,658)
Loss on disposal of assets	674	471	646
Gain on recovery of insurance proceeds, property, equipment and expenses	(741)
Gain on recovery of insurance proceeds, lost profits	(502)
Impairment of property and equipment	8,400	181	293
Closed-store reserves	154	(89)	740
Amortization of deferred financing costs	304	304	1,302
Amortization of favorable and unfavorable leases, net	(82)	(156)	(227)
Excess income tax benefit related to share-based compensation plans	(169)	(5,420)	(3,965)
Deferred income taxes, net	12,390	15,249	(67,001)
Payment related to tax receivable agreement	(3,236)
Changes in operating assets and liabilities:
Accounts and other receivables, net	(844)	(427)	147
Inventories	(221)	1	(245)
Prepaid expenses and other current assets	(448)	2,452	(3,065)
Income taxes receivable/payable	222	5,589	3,836
Other assets	107	91	247
Accounts payable	(4,579)	2,317	(8,023)
Accrued salaries and vacation	(939)	(1,311)	(651)
Accrued insurance	423	1,203	221
Other accrued expenses and liabilities	1,996	(325)	(1,996)
Net cash provided by operating activities	49,299	57,971	26,085
Cash flows from investing activities
Proceeds from disposition of restaurant	1,465
Proceeds from fire insurance for property and equipment	743
Proceeds from disposition of assets			5,435
Purchase of property and equipment	(37,410)	(30,835)	(26,836)
Net cash flows used in investing activities	(35,202)	(30,835)	(21,401)
Cash flows from financing activities
Proceeds from borrowings on revolver and term loans			165,000
Payments on revolver loan	(19,000)	(42,000)
Proceeds from issuance of common stock for initial public offering, net of expenses			112,300
Proceeds from issuance of common stock upon exercise of stock options, net of expenses	978	4,254	2,070
Payment of call premium on notes			(1,526)
Payment of obligations under capital leases	(177)	(208)	(268)
Repayments on senior secured notes			(290,000)
Deferred financing costs for Revolver			(1,526)
Excess income tax benefit related to share-based compensation plans	169	5,420	3,965
Amendment fee			(215)
Net cash flows used in financing activities	(18,030)	(32,534)	(10,200)
Decrease in cash and cash equivalents	(3,933)	(5,398)	(5,516)
Cash and cash equivalents, beginning of year	6,101	11,499	17,015
Cash and cash equivalents, end of year	2,168	6,101	11,499
Supplemental cash flow information
Cash paid for interest, net of capitalized interest	3,086	3,487	20,224
Cash paid during the year for income taxes, net	171	18	156
Noncash investing and financing activity
Unpaid purchases of property and equipment	$ 5,158	3,201	1,235
Cashless stock option exercise		$ 34	$ 27