SEGMENTS AND ENTITY WIDE DISCLOSURES (Details 2) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2017 USD ($) region	Apr. 30, 2016 USD ($)	Oct. 31, 2016 USD ($)
Segment Reporting [Abstract]
Number of geographic regions in which entity operates | region			4
Ciena's geographic distribution of revenue
Revenue	$ 707,022	$ 640,717	$ 1,328,519	$ 1,213,832
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	299,792		299,792		$ 288,406
North America
Ciena's geographic distribution of revenue
Revenue	424,373	395,505	830,301	788,209
EMEA
Ciena's geographic distribution of revenue
Revenue	105,776	96,175	197,319	176,897
CALA
Ciena's geographic distribution of revenue
Revenue	33,971	57,896	69,117	101,706
APAC
Ciena's geographic distribution of revenue
Revenue	142,902	91,141	231,782	147,020
United States
Ciena's geographic distribution of revenue
Revenue	392,000	$ 367,100	771,700	$ 732,300
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	99,694		99,694		103,018
Canada
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	188,804		188,804		173,885
Other International
Ciena's geographic distribution of equipment, furniture and fixtures
Equipment, building, furniture and fixtures, net	$ 11,294		$ 11,294		$ 11,503