Share-Based Compensation Expense (Details Textual) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended	3 Months Ended			3 Months Ended
	Jan. 31, 2012	Jan. 31, 2012 Stock Options [Member] years	Oct. 31, 2011 Stock Options [Member]	Jan. 31, 2012 Restricted Stock Units (RSUs) [Member] years	Jan. 31, 2011 Restricted Stock Units (RSUs) [Member]	Jan. 31, 2012 2008 Plan [Member]	Jan. 31, 2012 2003 Employee Stock Purchase Plan [Member]	Jan. 31, 2012 2003 Employee Stock Purchase Plan [Member] Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of active equity compensation plans	2
Remaining authorized shares available for issuance						1.5		3.2
Vesting period of service-based awards		4 years		three or four-year
Intrinsic value of option exercised		$ 0.1	$ 1.4
Total fair value of restricted stock units vested and converted into common stock				7.3	10.8
Weighted average fair value of each restricted stock unit granted (per share)				$ 10.69	$ 19.25
Plan term (in years)							10 years
Shares authorized for issuance under plan							3.6
Maximum number of shares increase under ESPP								0.6
Offer period								6 months
ESPP Discount Percentage Purchase Date								15.00%
Shares issued under ESPP								0.6
Unrecognized share-based compensation	$ 71.3	$ 0.6		$ 70.7
Weighted-average period for recognition of share-based compensation (in years)		0.7		1.7