Changes in Cost Basis and Fair Value of Auction Rate Securities (Detail) (USD $) In Thousands, unless otherwise specified			9 Months Ended
Jul. 31, 2012	Oct. 31, 2011	Jul. 31, 2012 Cost Basis Auction Rate Securities	Jul. 31, 2012 Fair Value, Inputs, Level 3 Auction Rate Securities
Schedule of Available-for-sale Securities [Line Items]
Balance at beginning of year	$ 16,704	$ 15,670	$ 18,307	$ 15,670
Unrealized gains included in accumulated other comprehensive loss				2,477
Unrealized losses included in accumulated other comprehensive loss				(1,443)
Other-than-temporary credit losses recognized in earnings			(313)
Balance at ending of year	$ 16,704	$ 15,670	$ 17,994	$ 16,704

Total of debt securities categorized neither as held-to-maturity nor trading which are intended be sold or mature more than one year from the balance sheet date or operating cycle, if longer.

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+ Details

- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

+ References+ Details