RESTRUCTURING COSTS (Details) $ in Thousands		3 Months Ended
		Jan. 31, 2016 USD ($)	Jan. 31, 2015 USD ($) employee
Activity and balance of the restructuring liability accounts
Balance at beginning of period		$ 1,279	$ 1,315
Additional liability recorded		393
Restructuring costs		384	8,085
Adjustments to previous estimates		(9)
Cash payments		(761)	(4,974)
Balance at end of period		902	4,426
Current restructuring liabilities		707	3,940
Non-current restructuring liabilities		195	486
Workforce reduction
Activity and balance of the restructuring liability accounts
Balance at beginning of period		591	181
Additional liability recorded		393
Restructuring costs	[1]		8,081
Adjustments to previous estimates		0
Cash payments		(613)	(4,768)
Balance at end of period		371	3,494
Current restructuring liabilities		371	3,494
Non-current restructuring liabilities		0	$ 0
Workforce deduction | employee			125
Consolidation of excess facilities
Activity and balance of the restructuring liability accounts
Balance at beginning of period		688	$ 1,134
Additional liability recorded		0
Restructuring costs			4
Adjustments to previous estimates		(9)
Cash payments		(148)	(206)
Balance at end of period		531	932
Current restructuring liabilities		336	446
Non-current restructuring liabilities		$ 195	$ 486

[1] During the fiscal quarter ended January 31, 2015, Ciena recorded a charge of $8.1 million of severance and other employee-related costs associated with a global workforce reduction of approximately 125 employees.