Segment and Entity Wide Disclosures - Entity Wide Reporting (Details) $ in Thousands	12 Months Ended
	Oct. 31, 2018 USD ($) region	Oct. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of geographic regions | region	4
Ciena's geographic distribution of revenue
Revenues	$ 3,094,286	$ 2,801,687	$ 2,600,573
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	292,067	308,465
North America
Ciena's geographic distribution of revenue
Revenues	1,886,450	1,736,047	1,689,263
Canada
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	198,028	203,491
UNITED STATES
Ciena's geographic distribution of revenue
Revenues	1,770,000	1,630,000	1,580,000
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	75,479	90,482
EMEA
Ciena's geographic distribution of revenue
Revenues	464,876	404,099	393,705
CALA
Ciena's geographic distribution of revenue
Revenues	140,177	164,308	195,085
APAC
Ciena's geographic distribution of revenue
Revenues	602,783	497,233	$ 322,520
Other International
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	$ 18,560	$ 14,492