Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Cash flows provided by operating activities:
Net Income	$ 87,349	$ 98,414	$ 90,743
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	49,557	42,885	35,138
Impairment of assets	716	258	1,777
Loss on disposal of property, plant and equipment	616	515	434
Gain on sale of property, plant and equipment	(951)
Bad debt (recovery) expense	(244)	165	(16)
Stock-based compensation expense	6,148	6,665	6,857
Excess tax benefit from stock-based compensation arrangements	(12,524)	(15,350)	(17,353)
Deferred income taxes	8,243	6,986	15,350
Changes in operating assets and liabilities:
Accounts receivable	2,534	(2,289)	5,157
Inventories	445	(5,155)	5,090
Prepaid expenses, income tax receivable and other assets	14,936	11,858	(9,447)
Accounts payable	(1,811)	5,985	884
Accrued expenses and taxes and other current liabilities	5,479	9,014	4,578
Other liabilities	(6,304)	8,732	2,019
Net cash provided by operating activities	154,189	168,683	141,211
Cash flows used in investing activities:
Purchases of property, plant and equipment	(49,913)	(74,187)	(151,784)
Proceeds from sale of property, plant and equipment	3,855
Cash paid for intangible assets		(100)	(100)
Change in restricted cash	40	57	53
Net cash used in investing activities	(46,018)	(74,230)	(151,831)
Cash flows (used in) provided by financing activities:
Repurchase of Class A Common Stock	(164,658)	(135,705)	(7,859)
Proceeds from exercise of stock options	40,127	42,339	27,272
Cash paid on note payable and capital lease	(58)	(54)	(53)
Excess tax benefit from stock-based compensation arrangements	12,524	15,350	17,353
Net proceeds from sale of investment shares	736	1,408	785
Net cash (used in) provided by financing activities	(111,329)	(76,662)	37,498
Change in cash and cash equivalents	(3,158)	17,791	26,878
Cash and cash equivalents at beginning of year	94,193	76,402	49,524
Cash and cash equivalents at end of period	91,035	94,193	76,402
Supplemental disclosure of cash flow information:
Income taxes paid	30,978	45,078	42,324
Income taxes refunded	12,064	17,252
(Decrease) Increase in accounts payable for repurchase of Class A Common Stock	(3,000)	3,000
Increase (Decrease) in accounts payable for purchase of property, plant and equipment	$ 2,678	$ (1,843)	$ 268