Segments and Entity-Wide Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2017
Segment Reporting Information [Line Items]
Equipment, building, furniture and fixtures, net	$ 298,631		$ 298,631		$ 308,465
Maintenance spares, net	43,200		43,200
Net revenue	729,978	$ 707,022	1,376,113	$ 1,328,519
United States
Segment Reporting Information [Line Items]
Equipment, building, furniture and fixtures, net	81,051		81,051		$ 90,482
Net revenue	392,800	$ 392,000	776,100	$ 771,700
India
Segment Reporting Information [Line Items]
Net revenue	79,400
Networking Platforms
Segment Reporting Information [Line Items]
Other intangible assets, net	34,500		34,500
Software and Software-Related Services
Segment Reporting Information [Line Items]
Other intangible assets, net	$ 56,100		$ 56,100