Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 929	$ 6,589
Adjustments to reconcile net income to net cash used for operating activities:
Depreciation	15,259	14,115
Amortization	23,925	23,002
Stock-based compensation	15,233	9,023
Provision for excess and obsolete inventory	10,039	3,800
Deferred taxes	12,699	(6,183)
Other	(141)	(987)
Changes in operating assets and liabilities:
Accounts receivable	(58,882)	(13,191)
Inventories	2,635	(4,040)
Prepayments and other assets	(628)	(1,070)
Accounts payable and other accrued expenses	(45,487)	(47,404)
Deferred revenue and customer advances	9,632	(10,000)
Retirement plans contributions	(1,425)	(1,063)
Accrued income taxes	(9,609)	(9,085)
Net cash used for operating activities	(25,821)	(36,494)
Cash flows from investing activities:
Purchases of property, plant and equipment	(31,197)	(22,547)
Purchases of marketable securities	(257,260)	(124,514)
Proceeds from maturities of marketable securities	280,322	119,552
Proceeds from sales of marketable securities	101,363	21,694
Proceeds from life insurance	4,391
Net cash provided by (used for) investing activities	97,619	(5,815)
Cash flows from financing activities:
Issuance of common stock under employee stock purchase and stock option plans	10,165	8,921
Payments of long-term debt	(190,975)
Payments of contingent consideration		(313)
Net cash (used for) provided by financing activities	(180,810)	8,608
Decrease in cash and cash equivalents	(109,012)	(33,701)
Cash and cash equivalents at beginning of period	341,638	338,920
Cash and cash equivalents at end of period	$ 232,626	$ 305,219