Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jul. 02, 2011	Jul. 03, 2010	Jul. 02, 2011	Jul. 03, 2010
Income Statement [Abstract]
Product sales	$ 316,150	$ 275,425	$ 619,486	$ 528,467
Service sales	131,477	115,630	255,744	230,288
Total net sales	447,627	391,055	875,230	758,755
Cost of product sales	121,280	106,890	237,181	204,295
Cost of service sales	54,823	48,243	108,751	96,770
Total cost of sales	176,103	155,133	345,932	301,065
Gross profit	271,524	235,922	529,298	457,690
Selling and administrative expenses	125,439	106,939	242,563	213,632
Research and development expenses	23,014	20,807	45,268	40,883
Purchased intangibles amortization	2,504	2,592	5,005	5,234
Operating income	120,567	105,584	236,462	197,941
Interest expense	(5,052)	(3,621)	(9,135)	(6,235)
Interest income	813	448	1,526	777
Income from operations before income taxes	116,328	102,411	228,853	192,483
Provision for income taxes	16,253	17,489	34,289	32,043
Net income	$ 100,075	$ 84,922	$ 194,564	$ 160,440
Net income per basic common share	$ 1.09	$ 0.92	$ 2.12	$ 1.72
Weighted-average number of basic common shares	91,662	92,612	91,649	93,110
Net income per diluted common share	$ 1.07	$ 0.90	$ 2.09	$ 1.69
Weighted-average number of diluted common shares and equivalents	93,271	94,278	93,302	94,753