CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 27, 2018	Jun. 26, 2019	Jun. 27, 2018
Document Period End Date		Jun. 26, 2019
Finance Lease, Principal Payments		$ (912)	$ 0
OPERATING ACTIVITIES
Net income (including amounts attributable to non-controlling interests)	$ 10,571	14,778	15,550
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation expense	6,968	18,765	$ 13,466
Non-cash operating lease cost	$ 0	$ 18,765
Noncontrolling Interest, Weighted Average Ownership Percentage	24.80%	19.70%	25.60%
Equity-based compensation		$ 3,872	$ 2,834
Deferred income taxes		317	805
Non-cash interest expense		0	72
(Gain) loss on sale of marketable securities		(22)	16
Loss on disposal of property and equipment	$ 196	728	386
Unrealized (gain) loss on available-for-sale securities	23	(231)	61
Other non-cash expense		2	0
Net loss on sublease		0	672
Changes in operating assets and liabilities:
Accounts receivable		7,252	1,777
Inventories		57	20
Prepaid expenses and other current assets		(3,908)	105
Other assets		(5,354)	(487)
Accounts payable		(5,202)	188
Accrued expenses		3,870	2,590
Accrued wages and related liabilities		(1,271)	587
Other current liabilities		862	(661)
Deferred rent		0	(71)
Long-term operating lease liabilities		(17,408)	0
Other long-term liabilities		19	2,964
NET CASH PROVIDED BY OPERATING ACTIVITIES		35,891	40,874
INVESTING ACTIVITIES
Purchases of property and equipment		(55,998)	(36,364)
Purchases of marketable securities		(715)	(570)
Sales of marketable securities		27,000	2,144
NET CASH USED IN INVESTING ACTIVITIES		(29,713)	(34,790)
FINANCING ACTIVITIES
Proceeds from deemed landlord financing		0	559
Payments on deemed landlord financing		0	(167)
Distributions paid to non-controlling interest holders	(587)	(1,667)	(670)
Payments under tax receivable agreement	0	(707)	0
Proceeds from stock option exercises		3,427	3,566
Payment, Tax Withholding, Share-based Payment Arrangement		(1,336)	0
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES		(1,195)	3,288
NET INCREASE IN CASH AND CASH EQUIVALENTS		4,983	9,372
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD		24,750	21,507
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 30,879	$ 29,733	$ 30,879