CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Apr. 03, 2016	Apr. 05, 2015
Cash flows from operating activities:
Net income	$ 49,986	$ 32,787
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	16,192	19,345
Amortization	20,470	15,139
Stock-based compensation	7,925	7,963
Provision for excess and obsolete inventory	4,373	1,440
Contingent consideration adjustment	1,173
Deferred taxes	(5,496)	(1,831)
Retirement plans actuarial gains	(1,193)
Gain from the sale of an equity investment		(4,782)
Other	484	(1,417)
Changes in operating assets and liabilities:
Accounts receivable	(42,552)	(24,749)
Inventories	(702)	5,960
Prepayments and other assets	(1,148)	3,146
Accounts payable and other accrued expenses	(7,626)	(20,150)
Deferred revenue and customer advances	(13,836)	1,038
Retirement plans contributions	(1,250)	(1,019)
Income taxes	(52)	4,662
Net cash provided by operating activities	26,748	37,532
Cash flows from investing activities:
Purchases of property, plant and equipment	(20,334)	(21,149)
Purchases of available-for-sale marketable securities	(221,778)	(335,635)
Proceeds from sales of available-for-sale marketable securities	239,370	148,639
Proceeds from maturities of available-for-sale marketable securities	73,458	140,222
Proceeds from the sale of an equity investment		4,782
Proceeds from life insurance		1,098
Net cash provided by (used for) investing activities	70,716	(62,043)
Cash flows from financing activities:
Issuance of common stock under employee stock purchase and stock option plans	9,140	8,899
Repurchase of common stock	(28,001)	(46,650)
Dividend payments	(12,253)	(13,049)
Payments of contingent consideration	(11,697)
Net cash used for financing activities	(42,811)	(50,800)
Increase (decrease) in cash and cash equivalents	54,653	(75,311)
Cash and cash equivalents at beginning of period	264,705	294,256
Cash and cash equivalents at end of period	$ 319,358	$ 218,945