Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014
Cash flows provided by operating activities:
Net Income	$ 82,299	$ 71,669
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	31,577	24,990
Impairment of assets	218	1,577
Loss on disposal of property, plant and equipment	342	91
Bad debt expense	12	160
Stock-based compensation expense	5,218	5,324
Excess tax benefit from stock-based compensation arrangements	(13,113)	(9,158)
Deferred income taxes	(1,012)	157
Changes in operating assets and liabilities:
Accounts receivable	(20,273)	(7,830)
Inventories	(6,010)	(3,213)
Prepaid expenses, income tax receivable and other assets	20,662	(4,862)
Accounts payable	12,167	2,029
Accrued expenses and other current liabilities	22,609	21,650
Other liabilities	7,777	(20)
Net cash provided by operating activities	142,473	102,564
Cash flows used in investing activities:
Purchases of property, plant and equipment	(55,606)	(128,292)
Cash paid for other intangible assets	(100)	(100)
Decrease in restricted cash	57	55
Net cash used in investing activities	(55,649)	(128,337)
Cash flows (used in) provided by financing activities:
Repurchase of Class A Common Stock	(83,794)	0
Proceeds from exercise of stock options	41,000	23,441
Cash paid on note payable	(54)	(53)
Excess tax benefit from stock-based compensation arrangements	13,113	9,158
Net proceeds from sale of investment shares	1,121	881
Net cash (used in) provided by financing activities	(28,614)	33,427
Change in cash and cash equivalents	58,210	7,654
Cash and cash equivalents at beginning of year	76,402	49,524
Cash and cash equivalents at end of period	134,612	57,178
Supplemental disclosure of cash flow information:
Income taxes paid	23,992	23,191
Income taxes refunded	17,225	0
Increase in accounts payable for purchase of property, plant and equipment	$ 775	$ 3,390