Segment and Entity Wide Disclosures - Entity Wide Reporting (Details) $ in Thousands	12 Months Ended
	Oct. 31, 2019 USD ($) region	Oct. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of geographic regions | region	4
Ciena's geographic distribution of revenue
Revenues	$ 3,572,131	$ 3,094,286	$ 2,801,687
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	286,884	292,067
North America
Ciena's geographic distribution of revenue
Revenues	2,351,260	1,886,450	1,736,047
Canada
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	211,901	198,028
UNITED STATES
Ciena's geographic distribution of revenue
Revenues	2,250,000	1,770,000	1,630,000
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	58,119	75,479
EMEA
Ciena's geographic distribution of revenue
Revenues	566,718	464,876	404,099
CALA
Ciena's geographic distribution of revenue
Revenues	152,653	140,177	164,308
APAC
Ciena's geographic distribution of revenue
Revenues	501,500	602,783	$ 497,233
Other International
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	$ 16,864	$ 18,560