Segments and Entity-Wide Disclosures - Revenue, Profit (Loss) and Net Income (Loss) Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Revenue:
Revenue	$ 729,978	$ 707,022	$ 1,376,113	$ 1,328,519
Segment profit:
Operating income (loss)	32,066	57,820	48,802	76,924
Less: Non-performance operating expenses
Selling and marketing	97,359	88,551	185,874	173,553
General and administrative	38,976	34,990	77,382	70,854
Amortization of intangible assets	3,623	10,980	7,246	25,531
Significant asset impairments and restructuring costs	4,359	4,276	10,320	6,671
Add: Other non-performance financial items
Interest expense and other income (loss), net	(11,735)	(16,226)	(23,894)	(31,059)
Less: Provision for income taxes	6,475	3,568	484,415	3,978
Net income (loss)	13,856	38,026	(459,507)	41,887
Operating Segments
Segment profit:
Operating income (loss)	176,383	196,617	329,624	353,533
Operating Segments \| Networking Platforms
Revenue:
Revenue	591,682	571,487	1,087,715	1,061,431
Segment profit:
Operating income (loss)	126,823	150,464	215,392	264,210
Operating Segments \| Networking Platforms \| Converged Packet Optical
Revenue:
Revenue	527,867	505,161	955,297	922,911
Operating Segments \| Networking Platforms \| Packet Networking
Revenue:
Revenue	63,815	66,326	132,418	138,520
Operating Segments \| Software and Software-Related Services
Revenue:
Revenue	38,745	37,716	92,232	77,096
Segment profit:
Operating income (loss)	8,276	4,551	31,911	77,071
Operating Segments \| Software and Software-Related Services \| Software Platforms
Revenue:
Revenue	12,544	13,143	42,120	30,192
Operating Segments \| Software and Software-Related Services \| Software-Related Services
Revenue:
Revenue	26,201	24,573	50,112	46,904
Operating Segments \| Global Services
Revenue:
Revenue	99,551	97,819	196,166	189,992
Segment profit:
Operating income (loss)	41,284	41,602	82,321	12,252
Operating Segments \| Global Services \| Maintenance Support and Training
Revenue:
Revenue	60,904	58,241	116,862	113,231
Operating Segments \| Global Services \| Installation and Deployment
Revenue:
Revenue	28,209	28,695	58,225	56,614
Operating Segments \| Global Services \| Consulting and Network Design
Revenue:
Revenue	$ 10,438	$ 10,883	$ 21,079	$ 20,147

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