SEGMENT AND ENTITY WIDE DISCLOSURES - Schedule of Ciena's Geographic Distribution of Revenue and Long-lived Assets (Details) - USD ($) $ in Thousands	Aug. 01, 2026	Nov. 01, 2025
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Equipment, building, furniture and fixtures, net	$ 537,323	$ 425,392
Canada
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Equipment, building, furniture and fixtures, net	427,861	325,584
United States
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Equipment, building, furniture and fixtures, net	53,412	44,634
Other International
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Equipment, building, furniture and fixtures, net	$ 56,050	$ 55,174