Stock-Based Benefit Plans (Details 5) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2012	Apr. 30, 2011	Oct. 31, 2011	Dec. 20, 2011	Dec. 20, 2010
RSU Expense Recognized
RSU expense recognized	$ 3,205	$ 2,345	$ 8,831	$ 7,717
Non-Performance Based Restricted Stock Units [Member]
Non-Performance Based Restricted Stock Units
Issuance of restricted stock and stock units, shares			107,820		15,497
Closing price of the Company's common stock on date of issuance						$ 20.50	$ 19.32
Aggregate fair value of RSUs issued			2,210		299
RSU Expense Recognized
RSU expense recognized	$ 311	$ 39	$ 625	$ 66