Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenue	$ 3,572,131	$ 3,094,286	$ 2,801,687
Products and services at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	3,003,347
Products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue	568,784
Converged Packet Optical
Disaggregation of Revenue [Line Items]
Total revenue	2,562,841
Packet Networking
Disaggregation of Revenue [Line Items]
Total revenue	348,477
Platform Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	155,376
Blue Planet Automation Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	54,555
Maintenance Support and Training
Disaggregation of Revenue [Line Items]
Total revenue	261,337
Installation and Deployment
Disaggregation of Revenue [Line Items]
Total revenue	148,233
Consulting and Network Design
Disaggregation of Revenue [Line Items]
Total revenue	41,312
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	3,572,131	3,094,286	2,801,687
Networking Platforms
Disaggregation of Revenue [Line Items]
Total revenue	2,911,318
Networking Platforms | Products and services at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	2,911,318
Networking Platforms | Products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue	0
Networking Platforms | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	2,911,318	2,478,018	2,252,710
Networking Platforms | Operating Segments | Converged Packet Optical
Disaggregation of Revenue [Line Items]
Total revenue	2,562,841	2,194,519	1,939,621
Networking Platforms | Operating Segments | Packet Networking
Disaggregation of Revenue [Line Items]
Total revenue	348,477	283,499	313,089
Networking Platforms | Operating Segments | Platform Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	0
Networking Platforms | Operating Segments | Blue Planet Automation Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	0
Networking Platforms | Operating Segments | Maintenance Support and Training
Disaggregation of Revenue [Line Items]
Total revenue	0
Networking Platforms | Operating Segments | Installation and Deployment
Disaggregation of Revenue [Line Items]
Total revenue	0
Networking Platforms | Operating Segments | Consulting and Network Design
Disaggregation of Revenue [Line Items]
Total revenue	0
Platform Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	155,376
Platform Software and Services | Products and services at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	55,530
Platform Software and Services | Products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue	99,846
Platform Software and Services | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	155,376
Platform Software and Services | Operating Segments | Converged Packet Optical
Disaggregation of Revenue [Line Items]
Total revenue	0
Platform Software and Services | Operating Segments | Packet Networking
Disaggregation of Revenue [Line Items]
Total revenue	0
Platform Software and Services | Operating Segments | Platform Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	155,376	173,949	145,009
Platform Software and Services | Operating Segments | Blue Planet Automation Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	0
Platform Software and Services | Operating Segments | Maintenance Support and Training
Disaggregation of Revenue [Line Items]
Total revenue	0
Platform Software and Services | Operating Segments | Installation and Deployment
Disaggregation of Revenue [Line Items]
Total revenue	0
Platform Software and Services | Operating Segments | Consulting and Network Design
Disaggregation of Revenue [Line Items]
Total revenue	0
Blue Planet Automation Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	54,555
Blue Planet Automation Software and Services | Products and services at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	17,697
Blue Planet Automation Software and Services | Products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue	36,858
Blue Planet Automation Software and Services | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	54,555
Blue Planet Automation Software and Services | Operating Segments | Converged Packet Optical
Disaggregation of Revenue [Line Items]
Total revenue	0
Blue Planet Automation Software and Services | Operating Segments | Packet Networking
Disaggregation of Revenue [Line Items]
Total revenue	0
Blue Planet Automation Software and Services | Operating Segments | Platform Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	0
Blue Planet Automation Software and Services | Operating Segments | Blue Planet Automation Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	54,555	26,764	16,110
Blue Planet Automation Software and Services | Operating Segments | Maintenance Support and Training
Disaggregation of Revenue [Line Items]
Total revenue	0
Blue Planet Automation Software and Services | Operating Segments | Installation and Deployment
Disaggregation of Revenue [Line Items]
Total revenue	0
Blue Planet Automation Software and Services | Operating Segments | Consulting and Network Design
Disaggregation of Revenue [Line Items]
Total revenue	0
Global Services
Disaggregation of Revenue [Line Items]
Total revenue	450,882
Global Services | Products and services at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	18,802
Global Services | Products and services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue	432,080
Global Services | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue	450,882	415,555	387,858
Global Services | Operating Segments | Converged Packet Optical
Disaggregation of Revenue [Line Items]
Total revenue	0
Global Services | Operating Segments | Packet Networking
Disaggregation of Revenue [Line Items]
Total revenue	0
Global Services | Operating Segments | Platform Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	0
Global Services | Operating Segments | Blue Planet Automation Software and Services
Disaggregation of Revenue [Line Items]
Total revenue	0
Global Services | Operating Segments | Maintenance Support and Training
Disaggregation of Revenue [Line Items]
Total revenue	261,337	245,161	227,400
Global Services | Operating Segments | Installation and Deployment
Disaggregation of Revenue [Line Items]
Total revenue	148,233	128,829	117,524
Global Services | Operating Segments | Consulting and Network Design
Disaggregation of Revenue [Line Items]
Total revenue	$ 41,312	$ 41,565	$ 42,934