CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 29, 2017	Mar. 30, 2016
OPERATING ACTIVITIES
Net income (including amounts attributable to non-controlling interests)	$ 3,862,000	$ 3,351,000
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation expense	4,748,000	3,106,000
Equity-based compensation	1,249,000	1,030,000
Deferred income taxes	(1,009,000)	3,000
Non-cash interest expense	71,000	70,000
Excess tax benefits on equity-based compensation	0	(28,000)
Loss on sale of marketable securities	3,000	0
Loss on disposal of property and equipment	(13,000)	0
Changes in operating assets and liabilities:
Accounts receivable	2,312,000	1,019,000
Inventories	(97,000)	(78,000)
Prepaid expenses and other current assets	(505,000)	345,000
Other assets	(520,000)	(234,000)
Accounts payable	400,000	561,000
Accrued expenses	1,029,000	(89,000)
Accrued wages and related liabilities	(2,057,000)	(2,086,000)
Other current liabilities	62,000	202,000
Deferred rent	164,000	1,354,000
Other long-term liabilities	(46,000)	(48,000)
NET CASH PROVIDED BY OPERATING ACTIVITIES	9,679,000	8,478,000
INVESTING ACTIVITIES
Purchases of property and equipment	(13,132,000)	(14,128,000)
Purchases of marketable securities	(325,000)	0
Sales of marketable securities	5,155,000	0
NET CASH USED IN INVESTING ACTIVITIES	(8,302,000)	(14,128,000)
FINANCING ACTIVITIES
Proceeds from Deemed Landlord Financing	293,000	0
Payments On Deemed Landlord Financing	(36,000)	0
Distributions paid to non-controlling interest holders	(355,000)	0
Tax Receivable Agreement Payments To Related Parties	(1,471,000)	0
Proceeds from stock option exercises	4,296,000	628,000
Excess tax benefits from equity-based compensation	0	28,000
NET CASH PROVIDED BY FINANCING ACTIVITIES	2,727,000	656,000
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	4,104,000	$ (4,994,000)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	11,607,000
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 15,711,000