Significant Accounting Policies - Cumulative Effect of the Changes Made to Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Nov. 01, 2018	Oct. 31, 2018
Assets [Abstract]
Accounts receivable, net	$ 761,186		$ 786,502
Accounts receivable, net		$ 799,011
Inventories	323,106	260,265	262,751
Prepaid expenses and other	217,422	220,415	198,945
Deferred tax asset, net	728,139	730,600	745,039
Other long-term assets	74,614	75,650	71,652
Total assets	3,618,106	3,777,575	3,756,523
Liabilities and Equity [Abstract]
Deferred revenue	85,501	96,731	111,134
Long-term deferred revenue	50,640	43,973	58,323
Accumulated deficit	(4,864,231)	(4,897,847)	(4,947,652)
Total liabilities and stockholders’ equity	3,618,106	3,777,575	3,756,523
Capitalized Contract Acquisition Costs
Liabilities and Equity [Abstract]
Capitalized acquisition costs, short term	$ 8,650		$ 0
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Assets [Abstract]
Accounts receivable, net		12,509
Inventories		(2,486)
Prepaid expenses and other		21,470
Deferred tax asset, net		(14,439)
Other long-term assets		3,998
Total assets		21,052
Liabilities and Equity [Abstract]
Deferred revenue		(14,403)
Long-term deferred revenue		(14,350)
Total liabilities and stockholders’ equity		21,052
Difference between Revenue Guidance in Effect before and after Topic 606 | Multiple Element Software Arrangements | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Deferred revenue		(23,600)
Long-term deferred revenue		(18,600)
Difference between Revenue Guidance in Effect before and after Topic 606 | Product Sales Other Than Multiple Element Software Arrangements | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Deferred revenue		(1,700)
Difference between Revenue Guidance in Effect before and after Topic 606 | Maintenance Services Other Than Multiple Element Software Arrangements | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Deferred revenue		(2,700)
Difference between Revenue Guidance in Effect before and after Topic 606 | Products and Services With Unpaid Invoices | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Deferred revenue		8,200
Long-term deferred revenue		4,300
Difference between Revenue Guidance in Effect before and after Topic 606 | Unbilled Accounts Receivable, Installation Services | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Capitalized acquisition costs, short term		27,500
Difference between Revenue Guidance in Effect before and after Topic 606 | Unbilled Accounts Receivable, Products | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Capitalized acquisition costs, short term		3,900
Difference between Revenue Guidance in Effect before and after Topic 606 | Capitalized Contract Acquisition Costs | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Capitalized acquisition costs, short term		9,600
Capitalized acquisition costs, long term		4,000
Difference between Revenue Guidance in Effect before and after Topic 606 | Prepaid Costs of Installation Services | Accounting Standards Update 2014-09
Liabilities and Equity [Abstract]
Capitalized acquisition costs, short term		$ (19,500)