Basis of Presentation and Summary of Significant Accounting Policies New Accounting Standards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 31, 2017	Dec. 30, 2017
Statement of Financial Position [Abstract]
Receivables, net	$ 225,822			$ 190,426
Prepaid expenses and other	61,597			63,811
Long-term receivables	9,380			12,239
Other assets	226,998			230,301
Accounts payable and accrued liabilities	210,784			221,101
Current portion of deferred revenue	310,639			336,297
Long-term portion of deferred revenue	56,276			61,513
Retained earnings	499,817		$ 426,932	341,003
Accumulated other comprehensive income	5,940			$ (3,630)
Income Statement [Abstract]
Product and maintenance revenue	480,609	$ 451,407
Services revenue	36,704	25,504
Cost of product and maintenance	41,730	43,717
Marketing and sales expense	109,148	103,347
Provision for income taxes	5,284	5,923
Net income	$ 72,885	$ 68,259
Net income per share - basic (in usd per share)	$ 0.27	$ 0.25
Net income per share - diluted (in usd per share)	$ 0.26	$ 0.25
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	$ 72,885	$ 68,259
Receivables	(10,988)	(22,475)
Prepaid expenses and other	8,392	(3,777)
Other assets	8,152	(3,657)
Accounts payable and accrued liabilities	(46,956)	(46,159)
Deferred revenue	59,854	$ 34,325
Balances under Prior GAAP
Statement of Financial Position [Abstract]
Receivables, net	207,284
Prepaid expenses and other	56,342
Long-term receivables	9,949
Other assets	215,051
Accounts payable and accrued liabilities	170,427
Current portion of deferred revenue	389,101
Long-term portion of deferred revenue	60,551
Retained earnings	419,941
Accumulated other comprehensive income	8,265
Income Statement [Abstract]
Product and maintenance revenue	486,789
Services revenue	38,668
Cost of product and maintenance	41,479
Marketing and sales expense	106,338
Provision for income taxes	5,841
Net income	$ 83,533
Net income per share - basic (in usd per share)	$ 0.31
Net income per share - diluted (in usd per share)	$ 0.30
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	$ 83,533
Receivables	(36,626)
Prepaid expenses and other	10,418
Other assets	6,410
Accounts payable and accrued liabilities	(58,597)
Deferred revenue	86,201
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	(18,538)		47,300
Prepaid expenses and other	(5,255)
Long-term receivables	569
Other assets	(11,947)
Accounts payable and accrued liabilities	(40,357)		23,300
Current portion of deferred revenue	78,462		57,400
Long-term portion of deferred revenue	4,275
Retained earnings	(79,876)		$ 85,400
Accumulated other comprehensive income	2,325
Income Statement [Abstract]
Product and maintenance revenue	6,180
Services revenue	1,964
Cost of product and maintenance	(251)
Marketing and sales expense	(2,810)
Provision for income taxes	557
Net income	$ 10,648
Net income per share - basic (in usd per share)	$ 0.04
Net income per share - diluted (in usd per share)	$ 0.04
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income	$ 10,648
Receivables	(25,638)
Prepaid expenses and other	2,026
Other assets	(1,742)
Accounts payable and accrued liabilities	(11,641)
Deferred revenue	$ 26,347