Net Income per Share - Reconciliation of Weighted Average Common Shares Used to Calculate Basic Net Income Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Apr. 30, 2015		Apr. 30, 2014		Apr. 30, 2015		Apr. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 55,596		$ 63,317		$ 120,785		$ 131,013
Weighted-average common shares for basic net income per share (shares)	154,515		154,572		154,486		154,319
Dilutive effect of potential common shares from equity-based compensation (shares)	2,968		2,510		2,923		2,667
Weighted-average common shares for diluted net income per share (shares)	157,483		157,082		157,409		156,986
Basic (in USD per share)	$ 0.36		$ 0.41		$ 0.78		$ 0.85
Diluted (in USD per share)	$ 0.35		$ 0.40		$ 0.77		$ 0.83
Anti-dilutive employee stock-based awards excluded (shares)	1,190	[1]	1,998	[1]	1,859	[1]	1,674	[1]

[1] These stock options and unvested restricted stock units and restricted stock awards were anti-dilutive for the respective periods and are excluded in calculating diluted net income per share. While such awards were antidilutive for the respective periods, they could be dilutive in the future.