Segments and Entity-Wide Disclosures - Revenue by Major Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Revenue, Major Customer [Line Items]
Total revenue	$ 818,817	$ 728,719	$ 2,194,930	$ 2,057,238
Customer concentration risk | Sales revenue, net
Revenue, Major Customer [Line Items]
Total revenue	270,856	203,849	484,928	531,172
Verizon | Customer concentration risk | Sales revenue, net
Revenue, Major Customer [Line Items]
Total revenue	97,103	82,918	221,475	206,272
AT&T | Customer concentration risk | Sales revenue, net
Revenue, Major Customer [Line Items]
Total revenue	87,389	$ 120,931	$ 263,453	$ 324,900
Web-scale provider | Customer concentration risk | Sales revenue, net
Revenue, Major Customer [Line Items]
Total revenue	$ 86,364