Changes in the Cost Basis and Fair Value of the Auction Rate Securities (Detail) (USD $) In Thousands, unless otherwise specified			12 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011 Cost Basis Auction Rate Securities	Oct. 31, 2010 Cost Basis Auction Rate Securities	Oct. 31, 2011 Fair Value, Inputs, Level 3 Auction Rate Securities	Oct. 31, 2010 Fair Value, Inputs, Level 3 Auction Rate Securities	Oct. 31, 2009 Fair Value, Inputs, Level 3 Auction Rate Securities
Schedule of Available-for-sale Securities [Line Items]
Balance at beginning of year	$ 15,670	$ 20,171	$ 23,307	$ 23,434	$ 20,171		$ 19,531
Unrealized gains					537	1,075
Unrealized losses					(38)	(435)
Other-than-temporary credit loss recognized in earnings				(127)
Redemption of security by issuer			(5,000)		(5,000)
Balance at ending of the year	$ 15,670	$ 20,171	$ 18,307	$ 23,307	$ 15,670		$ 19,531