Basis of Presentation and Summary of Significant Accounting Policies New Accounting Standards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 532,468	$ 485,398	$ 1,568,172	$ 1,441,310
Statement of Financial Position [Abstract]
Receivables, net	240,836		240,836			$ 190,426
Prepaid expenses and other	66,979		66,979			63,811
Long-term receivables	4,395		4,395			12,239
Other assets	232,540		232,540			230,301
Accounts payable and accrued liabilities	212,153		212,153			221,101
Current portion of deferred revenue	329,168		329,168			336,297
Long-term portion of deferred revenue	49,343		49,343			61,513
Retained earnings	674,284		674,284		$ 426,932	341,003
Accumulated other comprehensive income	(22,351)		(22,351)			$ (3,630)
Income Statement [Abstract]
Marketing and sales expense	108,608	104,263	327,056	311,507
Provision for income taxes	241	5,390	20,401	19,552
Net income	$ 99,318	$ 81,157	$ 247,352	$ 218,543
Net income per share - basic	$ 0.36	$ 0.30	$ 0.90	$ 0.80
Net income per share - diluted	$ 0.35	$ 0.29	$ 0.88	$ 0.78
Net Cash Provided by (Used in) Operating Activities [Abstract]
Receivables			$ (28,471)	$ (9,539)
Prepaid expenses and other			2,018	(4,627)
Other assets			3,571	(14,469)
Accounts payable and accrued liabilities			(41,718)	(41,127)
Deferred revenue			77,370	14,245
Balances under Prior GAAP
Statement of Financial Position [Abstract]
Receivables, net	$ 219,189		219,189
Prepaid expenses and other	55,190		55,190
Long-term receivables	5,848		5,848
Other assets	219,877		219,877
Accounts payable and accrued liabilities	189,530		189,530
Current portion of deferred revenue	380,483		380,483
Long-term portion of deferred revenue	62,982		62,982
Retained earnings	586,558		586,558
Accumulated other comprehensive income	(21,602)		(21,602)
Income Statement [Abstract]
Marketing and sales expense	107,458		321,930
Provision for income taxes	2,194		22,760
Net income	$ 94,660		$ 251,265
Net income per share - basic	$ 0.35		$ 0.92
Net income per share - diluted	$ 0.34		$ 0.89
Net Cash Provided by (Used in) Operating Activities [Abstract]
Receivables			$ (51,039)
Prepaid expenses and other			9,901
Other assets			1,561
Accounts payable and accrued liabilities			(36,524)
Deferred revenue			84,958
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	$ (21,647)		(21,647)		47,300
Prepaid expenses and other	(11,789)		(11,789)
Long-term receivables	1,453		1,453
Other assets	(12,663)		(12,663)
Accounts payable and accrued liabilities	(22,623)		(22,623)		23,300
Current portion of deferred revenue	51,315		51,315		57,400
Long-term portion of deferred revenue	13,639		13,639
Retained earnings	(87,726)		(87,726)		$ 85,400
Accumulated other comprehensive income	749		749
Income Statement [Abstract]
Marketing and sales expense	(1,150)		(5,126)
Provision for income taxes	1,953		2,359
Net income	$ (4,658)		$ 3,913
Net income per share - basic	$ (0.01)		$ 0.02
Net income per share - diluted	$ (0.01)		$ 0.01
Net Cash Provided by (Used in) Operating Activities [Abstract]
Receivables			$ (22,568)
Prepaid expenses and other			7,883
Other assets			(2,010)
Accounts payable and accrued liabilities			5,194
Deferred revenue			7,588
Product and maintenance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 494,990	$ 451,229	1,463,469	1,346,483
Income Statement [Abstract]
Cost of sales	36,406	34,825	118,263	117,371
Product and maintenance | Balances under Prior GAAP
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	489,485		1,459,528
Income Statement [Abstract]
Cost of sales	33,752		115,472
Product and maintenance | Accounting Standards Update 2014-09 | Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	(5,505)		(3,941)
Income Statement [Abstract]
Cost of sales	(2,654)		(2,791)
Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	37,478	34,169	104,703	94,827
Income Statement [Abstract]
Cost of sales	24,048	$ 19,657	64,360	$ 59,735
Services | Balances under Prior GAAP
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	36,474		106,999
Services | Accounting Standards Update 2014-09 | Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ (1,004)		$ 2,296