Condensed Consolidated Income Statements (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Revenues [Abstract]
Revenues	$ 580,419	$ 518,391	$ 1,157,161	$ 1,035,704
Costs and Expenses:
Marketing and sales	116,208	109,300	233,038	218,448
Research and development	231,814	219,129	460,024	443,314
General and administrative	34,407	34,875	64,509	68,174
Amortization of acquired intangibles	3,159	3,518	6,467	7,148
Restructuring and other credits	(313)	(447)	(1,002)	(2,438)
Total costs and expenses	446,744	425,335	895,090	856,815
Income from operations	133,675	93,056	262,071	178,889
Interest expense	4,976	6,669	10,367	13,644
Other income (expense), net	(110)	3,638	5,131	2,949
Income before provision for income taxes	128,589	90,025	256,835	168,194
Provision for income taxes	21,354	14,876	29,045	20,160
Net income	$ 107,235	$ 75,149	$ 227,790	$ 148,034
Net income per share – basic	$ 0.39	$ 0.27	$ 0.83	$ 0.54
Net income per share – diluted	$ 0.38	$ 0.27	$ 0.81	$ 0.53
Weighted average common shares outstanding – basic	273,159	273,564	273,155	273,703
Weighted average common shares outstanding – diluted	281,054	280,774	280,877	281,247
Product and maintenance [Member]
Revenues [Abstract]
Revenues	$ 548,028	$ 487,870	$ 1,091,546	$ 968,479
Costs and Expenses:
Cost of sales	43,388	40,127	93,910	81,857
Technology Service [Member]
Revenues [Abstract]
Revenues	32,391	30,521	65,615	67,225
Costs and Expenses:
Cost of sales	$ 18,081	$ 18,833	$ 38,144	$ 40,312