Net Income per Share - Reconciliation of Weighted Average Common Shares Used to Calculate Basic Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Numerator:
Net income	$ 102,472	$ 53,306	$ 98,781	$ 139,894
Denominator:
Weighted-average common shares for basic net income per share (shares)	149,034	150,384	149,245	150,583
Dilutive effect of potential common shares from equity-based compensation (shares)	4,133	4,477	4,419	4,171
Weighted-average common shares for diluted net income per share (shares)	153,167	154,861	153,664	154,754
Net income per share:
Basic (in USD per share)	$ 0.69	$ 0.35	$ 0.66	$ 0.93
Diluted (in USD per share)	$ 0.67	$ 0.34	$ 0.64	$ 0.90
Anti-dilutive employee stock-based awards excluded (shares)	761	948	618	738