Components of Other Current Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jan. 31, 2012		Oct. 31, 2011		Jul. 31, 2011		Apr. 30, 2011		Jan. 31, 2011		Oct. 31, 2010		Jul. 31, 2010		Apr. 30, 2010		Jan. 31, 2010		Oct. 31, 2009
Other Liabilities Current [Line Items]
Accrued Pricing Liabilities	$ 20,397					$ 30,706	[1]							$ 42,282	[1]
Other	6,381					7,918	[1]							5,367	[1]
Other current liabilities	$ 26,778	$ 39,489	[1]	$ 39,765	[1]	$ 38,624	[1]	$ 39,228	[1]	$ 44,641	[1]	$ 43,230	[1]	$ 47,649	[1]	$ 46,265	[1]	$ 46,068	[1]	$ 43,766	[1]

[1] As Restated