Business Combinations (Details Textual) (USD $)	12 Months Ended			0 Months Ended		3 Months Ended		7 Months Ended		12 Months Ended
	Oct. 31, 2011 months years	Oct. 31, 2010	Oct. 31, 2009	Oct. 31, 2010 MEN Business [Member]	Mar. 19, 2010 MEN Business [Member]	Jan. 31, 2011 MEN Business [Member]	Oct. 31, 2010 MEN Business [Member]	Oct. 19, 2010 MEN Business [Member]	Oct. 31, 2010 MEN Business [Member]	Oct. 31, 2011 MEN Business [Member]	Oct. 31, 2010 MEN Business [Member]	Oct. 31, 2011 MEN Business [Member] Developed Technology Rights [Member] years	Oct. 31, 2011 MEN Business [Member] Customer Relationships, Outstanding Purchase Orders And Contracts [Member] years	Oct. 31, 2011 MEN Business [Member] Trade Names [Member] months	Oct. 31, 2011 MEN Business [Member] Order or Production Backlog [Member]	Mar. 19, 2010 MEN Business [Member] Order or Production Backlog [Member]
Business Combinations (Textuals) [Abstract]
Initial purchase price agreement					$ 773,800,000
Aggregate purchase price subsequently adjusted downward upon net working capital transferred to Ciena at closing									80,600,000
Initial cash paid for purchase of business	0	693,247,000	0		693,200,000
Period of lease term in connection with the acquisition related to Nortel to lease Lab 10 building								10 years
Contingent refund					33,500,000
Shortened period of lease term in connection with early termination rights under the lease as directed by governmental authorities				5 years
Gain recorded	3,289,000	13,807,000	0			3,300,000	13,800,000
Fair value of contingent refund right				30,200,000	16,400,000		30,200,000		30,200,000		30,200,000
Final purchase price				676,800,000			676,800,000		676,800,000		676,800,000
Payment received on early termination of lease						33,500,000
Transaction, consulting and third party service fees	42,088,000	101,379,000	0							42,100,000	101,400,000
Restructuring costs	5,781,000	8,514,000	11,207,000							6,600,000	8,500,000
Additional related to purchases of capitalized information technology equipment										10,900,000	12,400,000
Estimated useful lives on straight line basis, minimum (in years)	9											2	0.75
Estimated useful lives on straight line basis, maximum (in years)	7											7	7
In-process research and development amortization period										7 years
Contract intangible asset related to acquired projects in-process															800,000	14,600,000
Contract intangible assets billed															$ 13,800,000
Expected useful life (in months)														9