Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Cash flows provided by operating activities:
Net income	$ 99,049	$ 87,349	$ 98,414
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	51,256	49,557	42,885
Impairment of assets	2,451	716	258
Loss on disposal of property, plant and equipment	764	616	515
Gain on sale of property, plant and equipment		(951)
Bad debt (recovery) expense		(244)	165
Stock-based compensation expense	6,316	6,148	6,665
Excess tax benefit from stock-based compensation arrangements		(12,524)	(15,350)
Deferred income taxes	(22,442)	8,243	6,986
Changes in operating assets and liabilities:
Accounts receivable	2,945	2,534	(2,289)
Inventories	(1,741)	445	(5,155)
Prepaid expenses, income tax receivable and other assets	(4,511)	14,936	11,858
Accounts payable	245	(1,811)	5,985
Accrued expenses and taxes and other current liabilities	2,671	5,479	9,014
Other liabilities	(1,021)	(6,304)	8,732
Net cash provided by operating activities	135,982	154,189	168,683
Cash flows used in investing activities:
Purchases of property, plant and equipment	(32,987)	(49,913)	(74,187)
Proceeds from sale of property, plant and equipment	25	3,855
Cash paid for intangible assets			(100)
Change in restricted cash	33	40	57
Net cash used in investing activities	(32,929)	(46,018)	(74,230)
Cash flows used in financing activities:
Repurchase of Class A Common Stock	(144,602)	(164,658)	(135,705)
Proceeds from exercise of stock options	15,415	40,127	42,339
Cash paid on note payable and capital lease	(60)	(58)	(54)
Excess tax benefit from stock-based compensation arrangements		12,524	15,350
Net proceeds from sale of investment shares	796	736	1,408
Net cash used in financing activities	(128,451)	(111,329)	(76,662)
Change in cash and cash equivalents	(25,398)	(3,158)	17,791
Cash and cash equivalents at beginning of year	91,035	94,193	76,402
Cash and cash equivalents at end of period	65,637	91,035	94,193
Supplemental disclosure of cash flow information:
Income taxes paid	43,006	30,978	45,078
Income taxes refunded		12,064	17,252
(Decrease) Increase in accounts payable for repurchase of Class A Common Stock		(3,000)	3,000
(Decrease) Increase in accounts payable for purchase of property, plant and equipment	$ (2,689)	$ 2,678	$ (1,843)