Summary of Significant Accounting Policies - Components of Accounts Receivables (Details) - USD ($) $ in Thousands	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Accounts, Notes, Loans and Financing Receivable, Net, Current [Abstract]
Accounts receivable	$ 524,766	$ 495,763
Unbilled accounts receivable	38,175	64,067
Total accounts receivable	562,941	559,830
Less allowance for doubtful accounts	(9,046)	(5,613)	$ (5,165)	$ (3,201)
Total accounts receivable, net	$ 553,895	$ 554,217