SEGMENTS AND ENTITY WIDE DISCLOSURES (Details 2) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)	Apr. 30, 2016 USD ($) region	Apr. 30, 2015 USD ($)	Oct. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of geographic regions in which entity operates | region			4
Ciena's geographic distribution of revenue
Revenue	$ 640,717	$ 621,602	$ 1,213,832	$ 1,150,764
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	248,649		248,649		$ 191,973
North America
Ciena's geographic distribution of revenue
Revenue	395,505	397,181	788,209	728,716
EMEA
Ciena's geographic distribution of revenue
Revenue	96,175	102,194	176,897	213,200
CALA
Ciena's geographic distribution of revenue
Revenue	57,896	47,891	101,706	90,633
APAC
Ciena's geographic distribution of revenue
Revenue	91,141	74,336	147,020	118,215
United States
Ciena's geographic distribution of revenue
Revenue	367,100	$ 367,600	732,300	$ 665,300
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	97,327		97,327		96,292
Canada
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	140,056		140,056		84,318
Other International
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	$ 11,266		$ 11,266		$ 11,363