Significant Accounting Policies - Cumulative Effect of the Changes Made to Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Nov. 01, 2018	Oct. 31, 2018
ASSETS:
Accounts receivable, net	$ 756,607		$ 786,502
Accounts receivable, net	756,607	$ 799,011
Inventories	359,417	260,265	262,751
Prepaid expenses and other	243,669	220,415	198,945
Deferred tax asset, net	715,968	730,600	745,039
Other long-term assets	82,938	75,650	71,652
Total assets	3,686,778	3,777,575	3,756,523
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Deferred revenue	104,030	96,731	111,134
Long-term deferred revenue	40,992	43,973	58,323
Accumulated deficit	(4,811,493)	(4,897,847)	(4,947,652)
Total liabilities and stockholders’ equity	3,686,778	3,777,575	3,756,523
Capitalized Contract Acquisition Costs
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Capitalized acquisition costs, short term	$ 8,373		$ 0
Adjustments | Accounting Standards Update 2014-09
ASSETS:
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 STOCKHOLDERS’ EQUITY:
Deferred revenue		(14,403)
Long-term deferred revenue		(14,350)
Accumulated deficit		49,805
Total liabilities and stockholders’ equity		21,052
Adjustments | Multiple Element Software Arrangements | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Deferred revenue		(23,600)
Long-term deferred revenue		(18,600)
Adjustments | Product Sales Other Than Multiple Element Software Arrangements | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Deferred revenue		(1,700)
Adjustments | Maintenance Services Other Than Multiple Element Software Arrangements | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Deferred revenue		2,700
Adjustments | Products and Services With Unpaid Invoices | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Deferred revenue		8,200
Long-term deferred revenue		4,300
Adjustments | Unbilled Accounts Receivable, Installation Services | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Capitalized acquisition costs, short term		27,500
Adjustments | Unbilled Accounts Receivable, Products | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Capitalized acquisition costs, short term		3,900
Adjustments | Capitalized Contract Acquisition Costs | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Capitalized acquisition costs, short term		9,600
Capitalized acquisition costs, long term		4,000
Adjustments | Prepaid Costs of Installation Services | Accounting Standards Update 2014-09
LIABILITIES AND STOCKHOLDERS’ EQUITY:
Capitalized acquisition costs, short term		$ (19,500)