Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 102,134	$ 73,145
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	33,785	27,552
Amortization	42,990	46,052
Stock-based compensation	23,530	18,077
Provision for excess and obsolete inventory	15,071	5,775
Deferred taxes	(5,697)	(15,230)
Tax benefit related to stock options and restricted stock units	(1,671)	(1,584)
Retirement plans actuarial gains		(1,359)
Other	1,165	24
Changes in operating assets and liabilities:
Accounts receivable	(143,125)	(74,785)
Inventories	18,469	26,373
Prepayments and other assets	27,000	(17,277)
Accounts payable and other accrued expenses	52,796	(15,428)
Deferred revenue and customer advances	13,800	(2,811)
Retirement plans contributions	(2,388)	(2,511)
Accrued income taxes	5,495	2,964
Net cash provided by operating activities	183,354	68,977
Cash flows from investing activities:
Purchases of property, plant and equipment	(91,389)	(50,798)
Purchases of marketable securities	(523,306)	(458,070)
Proceeds from maturities of marketable securities	377,436	268,546
Proceeds from sales of marketable securities	152,818	50,255
Proceeds from life insurance	4,391
Net cash used for investing activities	(80,050)	(190,067)
Cash flows from financing activities:
Issuance of common stock under employee stock purchase and stock options plans	10,643	9,638
Tax benefit related to stock options and restricted stock units	1,671	1,584
Payments of dividend	(11,656)
Payments of long-term debt	(190,975)	(1,063)
Payments of contingent consideration		(388)
Net cash (used for) provided by financing activities	(190,317)	9,771
Decrease in cash and cash equivalents	(87,013)	(111,319)
Cash and cash equivalents at beginning of period	341,638	338,920
Cash and cash equivalents at end of period	$ 254,625	$ 227,601