Summary of Significant Accounting Policies - Components of Accounts Receivables (Details) - USD ($) $ in Thousands	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2014
Accounts, Notes, Loans and Financing Receivable, Net, Current [Abstract]
Accounts receivable	$ 393,229	$ 394,314
Unbilled accounts receivable	63,080	47,760
Total accounts receivable	456,309	442,074
Less allowance for doubtful accounts	(5,165)	(3,201)	$ (2,561)	$ (2,026)
Total accounts receivable, net	$ 451,144	$ 438,873