OTHER BALANCE SHEET DETAILS (Details) - USD ($) $ in Thousands		6 Months Ended
		Apr. 30, 2017	Apr. 30, 2016	Oct. 31, 2016
Other long-term assets
Maintenance spares, net		$ 48,447		$ 49,535
Deferred debt issuance costs, net	[1]	1,202		1,363
Financing receivable		0		1,870
Other		15,542		15,352
Total other long-term assets		65,191		$ 68,120
Other Balance Sheet Details (Textuals) [Abstract]
Amortization of debt issuance costs included in interest expense		$ 200	$ 300

[1] As described in Note 2 above, in connection with Ciena's adoption of ASU 2015-03 effective January 31, 2017, deferred debt issuance costs associated with its convertible notes and term loans were retrospectively reclassified from other long-term assets to current portion of long-term debt and long-term debt, net on the Condensed Consolidated Balance Sheets. The deferred debt issuance costs reflected relate to Ciena's ABL Credit Facility (described in Note 17 below). The amortization of deferred debt issuance costs for Ciena's ABL Credit Facility is included in interest expense, and was $0.2 million and $0.3 million during the first six months of fiscal 2017 and 2016, respectively.