Basis of Presentation and Summary of Significant Accounting Policies New Accounting Standards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 31, 2017	Dec. 30, 2017
Statement of Financial Position [Abstract]
Receivables, net	$ 219,072		$ 219,072			$ 190,426
Prepaid expenses and other	56,042		56,042			63,811
Long-term receivables	4,740		4,740			12,239
Other assets	227,173		227,173			230,301
Accounts payable and accrued liabilities	243,158		243,158			221,101
Current portion of deferred revenue	327,078		327,078			336,297
Long-term portion of deferred revenue	46,912		46,912			61,513
Retained earnings	574,966		574,966		$ 426,932	341,003
Accumulated other comprehensive income	(13,172)		(13,172)			$ (3,630)
Income Statement [Abstract]
Product and maintenance revenue	487,870	$ 443,847	968,479	$ 895,254
Services revenue	30,521	35,154	67,225	60,658
Cost of product and maintenance	40,127	38,829	81,857	82,546
Marketing and sales expense	109,300	103,897	218,448	207,244
Provision for income taxes	14,876	8,239	20,160	14,162
Net income	$ 75,149	$ 69,127	$ 148,034	$ 137,386
Net income per share - basic	$ 0.27	$ 0.25	$ 0.54	$ 0.51
Net income per share - diluted	$ 0.27	$ 0.25	$ 0.53	$ 0.49
Net Cash Provided by (Used in) Operating Activities [Abstract]
Receivables			$ (2,606)	$ 6,342
Prepaid expenses and other			13,294	(1,557)
Other assets			5,622	(8,790)
Accounts payable and accrued liabilities			(11,832)	(21,995)
Deferred revenue			71,667	$ 18,733
Balances under Prior GAAP
Statement of Financial Position [Abstract]
Receivables, net	$ 199,744		199,744
Prepaid expenses and other	48,445		48,445
Long-term receivables	5,813		5,813
Other assets	215,407		215,407
Accounts payable and accrued liabilities	216,238		216,238
Current portion of deferred revenue	384,798		384,798
Long-term portion of deferred revenue	62,921		62,921
Retained earnings	491,898		491,898
Accumulated other comprehensive income	(14,531)		(14,531)
Income Statement [Abstract]
Product and maintenance revenue	483,254		970,043
Services revenue	31,857		70,525
Cost of product and maintenance	40,241		81,720
Marketing and sales expense	108,134		214,472
Provision for income taxes	14,725		20,566
Net income	$ 73,072		$ 156,605
Net income per share - basic	$ 0.27		$ 0.57
Net income per share - diluted	$ 0.26		$ 0.56
Net Cash Provided by (Used in) Operating Activities [Abstract]
Receivables			$ (30,079)
Prepaid expenses and other			17,740
Other assets			2,408
Accounts payable and accrued liabilities			(10,525)
Deferred revenue			88,030
Accounting Standards Update 2014-09
Statement of Financial Position [Abstract]
Retained earnings					91,640
Accounting Standards Update 2014-09 | Adjustments
Statement of Financial Position [Abstract]
Receivables, net	$ (19,328)		(19,328)		47,300
Prepaid expenses and other	(7,597)		(7,597)
Long-term receivables	1,073		1,073
Other assets	(11,766)		(11,766)
Accounts payable and accrued liabilities	(26,920)		(26,920)		23,300
Current portion of deferred revenue	57,720		57,720		57,400
Long-term portion of deferred revenue	16,009		16,009
Retained earnings	(83,068)		(83,068)		$ 85,400
Accumulated other comprehensive income	(1,359)		(1,359)
Income Statement [Abstract]
Product and maintenance revenue	(4,616)		1,564
Services revenue	1,336		3,300
Cost of product and maintenance	114		(137)
Marketing and sales expense	(1,166)		(3,976)
Provision for income taxes	(151)		406
Net income	$ (2,077)		$ 8,571
Net income per share - basic	$ 0.00		$ 0.03
Net income per share - diluted	$ (0.01)		$ 0.03
Net Cash Provided by (Used in) Operating Activities [Abstract]
Receivables			$ (27,473)
Prepaid expenses and other			4,446
Other assets			(3,214)
Accounts payable and accrued liabilities			1,307
Deferred revenue			$ 16,363