Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015
Cash flows from operating activities
Net income	$ 8,619	$ 18,339	$ 24,054
Adjustments to reconcile changes in net income to net cash provided by operating activities:
Depreciation and amortization	18,128	16,053	13,092
Stock-based compensation expense	1,056	1,063	539
Fire insurance proceeds for expenses paid and lost profit	0	611	0
Income tax receivable agreement (income) expense	(5,570)	352	156
Gain on disposition of restaurants	0	(28)	0
Loss on disposal of assets	799	674	471
Gain on recovery of insurance proceeds, property, equipment and expenses	0	(741)	0
Gain on recovery of insurance proceeds, lost profits	0	(502)	0
Impairment of property and equipment	32,594	8,400	181
Closed-store reserves	1,051	154	(89)
Amortization of deferred financing costs	304	304	304
Amortization of favorable and unfavorable leases, net	(119)	(82)	(156)
Excess income tax benefit related to share-based compensation plans	0	(169)	(5,420)
Deferred income taxes, net	250	12,390	15,249
Changes in operating assets and liabilities:
Accounts and other receivables, net	(294)	(844)	(427)
Inventories	(177)	(221)	1
Prepaid expenses and other current assets	425	(448)	2,452
Income taxes receivable/payable	(85)	222	5,589
Other assets	47	107	91
Accounts payable	1,088	(4,579)	2,317
Accrued salaries and vacation	1,585	(939)	(1,311)
Accrued insurance	407	423	1,203
Payment related to tax receivable agreement	(11,109)	(3,236)	0
Other accrued expenses and liabilities	4,547	1,996	(325)
Restricted cash	125	0	0
Net cash provided by operating activities	53,671	49,299	57,971
Cash flows from investing activities
Proceeds from disposition of restaurant	0	1,465	0
Proceeds from fire insurance for property and equipment	0	743	0
Purchase of property and equipment	(36,238)	(37,410)	(30,835)
Net cash flows used in investing activities	(36,238)	(35,202)	(30,835)
Cash flows from financing activities
Proceeds from borrowings on revolver and term loans	8,000	0	0
Payments on revolver loan	(19,000)	(19,000)	(42,000)
Proceeds from issuance of common stock upon exercise of stock options, net of expenses	93	978	4,254
Payment of obligations under capital leases	(144)	(177)	(208)
Excess income tax benefit related to share-based compensation plans	0	169	5,420
Net cash flows used in financing activities	(11,051)	(18,030)	(32,534)
Increase (decrease) in cash and cash equivalents	6,382	(3,933)	(5,398)
Cash and cash equivalents, beginning of year	2,168	6,101	11,499
Cash and cash equivalents, end of year	8,550	2,168	6,101
Supplemental cash flow information
Cash paid for interest, net of capitalized interest	3,314	3,086	3,487
Cash paid during the year for income taxes, net	336	171	18
Noncash investing and financing activity
Unpaid purchases of property and equipment	4,741	5,158	3,201
Cashless stock option exercise	$ 0	$ 0	$ 34