Stock Repurchase Program (Stock Repurchase Activities) (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	1 Months Ended		3 Months Ended		6 Months Ended
	Jan. 31, 2012	Sep. 30, 2011	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2012		Apr. 30, 2011
Stock Repurchase Program [Abstract]
Shares repurchased			624	6,191	2,474	[1]	8,609
Average purchase price per share			$ 32.04	$ 27.46	$ 29.64	[1]	$ 27.29
Aggregate purchase price			$ 20,000,000	$ 169,988,000	$ 73,335,000	[1]	$ 234,985,000
Reissuance of treasury stock			3,631	3,430	6,116	[1]	6,616
Settlement of equity forward contract	$ 20,000,000	$ 33,300,000

[1] Amount includes $20.0 million from the settlement of the January 2012 ASR equity forward contract and $33.3 million from the settlement of the September 2011 ASR equity forward contract.