Business Combinations (Details Textual) (USD $)	0 Months Ended	3 Months Ended		7 Months Ended		12 Months Ended
	Mar. 19, 2010	Jan. 31, 2011	Oct. 31, 2010	Oct. 19, 2010	Oct. 31, 2010	Oct. 31, 2012 M Y	Oct. 31, 2011	Oct. 31, 2010
Business Combinations (Textuals) [Abstract]
Initial cash paid for purchase of business						0	$ 0	$ 693,247,000
Gain recorded						0	3,289,000	13,807,000
Transaction, consulting and third party service fees						0	42,088,000	101,379,000
Restructuring costs						7,854,000	5,781,000	8,514,000
Restructuring Reserve, Period Expense						7,854,000	6,627,000	9,256,000
Estimated useful lives on straight line basis, maximum (in years)						7
MEN Business [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	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
Fair value of contingent refund right	16,400,000		30,200,000		30,200,000			30,200,000
Final purchase price			676,800,000		676,800,000			676,800,000
Shortened period of lease term in connection with early termination rights under the lease as directed by governmental authorities				5 years
Gain recorded		3,300,000	13,800,000
Payment received for reduction in term lease		33,500,000
Transaction, consulting and third party service fees							42,100,000	101,400,000
Restructuring costs								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
Estimated useful lives on straight line basis, maximum (in years)						7
In-process research and development amortization period						7 years
MEN Business [Member] | Developed Technology Rights [Member]
Business Combinations (Textuals) [Abstract]
Estimated useful lives on straight line basis, minimum (in years)						2
Estimated useful lives on straight line basis, maximum (in years)						7
MEN Business [Member] | Trade Names [Member]
Business Combinations (Textuals) [Abstract]
Expected useful life (in months)						9
MEN Business [Member] | Order or Production Backlog [Member]
Business Combinations (Textuals) [Abstract]
Contract intangible asset related to acquired projects in-process	$ 14,600,000