Stock Repurchases - Additional Information (Detail) (Class A Common Shares, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	149 Months Ended
	Jan. 31, 2015	Jan. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Common stock shares repurchased	4,568,297
Cost of common stock repurchased	$ 25.4
Shares Stock Repurchase Plan, August 19, 2002
Equity, Class of Treasury Stock [Line Items]
Approved number of shares to be repurchased	2,000,000	2,000,000
Common stock shares repurchased		1,033,344
Cost of common stock repurchased		$ 6.0