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, 2019	Jan. 31, 2019	Apr. 30, 2018	Jan. 31, 2018	Apr. 30, 2019	Apr. 30, 2018
Numerator:
Net income (loss)	$ 118,210	$ 153,514	$ 102,472	$ (3,691)	$ 271,724	$ 98,781
Denominator:
Weighted-average common shares for basic net income per share (shares)	149,712		149,034		149,500	149,245
Dilutive effect of potential common shares from equity-based compensation (shares)	4,192		4,133		3,883	4,419
Weighted-average common shares for diluted net income per share (shares)	153,904		153,167		153,383	153,664
Net income per share:
Basic (in USD per share)	$ 0.79		$ 0.69		$ 1.82	$ 0.66
Diluted (in USD per share)	$ 0.77		$ 0.67		$ 1.77	$ 0.64
Anti-dilutive employee stock-based awards excluded (shares)	49		761		1,538	618