Condensed Consolidated Income Statements (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Revenues [Abstract]
Revenues	$ 617,957	$ 576,742
Costs and Expenses:
Marketing and sales	125,744	116,830
Research and development	241,668	228,210
General and administrative	33,592	30,102
Amortization of acquired intangibles	4,206	3,308
Restructuring and other credits	(1,067)	(689)
Total costs and expenses	478,606	448,346
Income from operations	139,351	128,396
Interest expense	(4,637)	(5,391)
Other income (expense), net	(4,534)	5,241
Income before provision for income taxes	130,180	128,246
Provision for income taxes	6,192	7,691
Net income	$ 123,988	$ 120,555
Net income per share – basic	$ 0.45	$ 0.44
Net income per share – diluted	$ 0.44	$ 0.43
Weighted average common shares outstanding – basic	273,476	273,066
Weighted average common shares outstanding – diluted	279,265	280,615
Product and maintenance [Member]
Revenues [Abstract]
Revenues	$ 581,699	$ 543,518
Costs and Expenses:
Cost of sales	55,446	50,522
Service [Member]
Revenues [Abstract]
Revenues	36,258	33,224
Costs and Expenses:
Cost of sales	$ 19,017	$ 20,063