Earnings Per Share (Schedule of Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Earnings Per Share [Abstract]
Net income	$ 75,136	$ 54,921	$ 149,803	$ 109,544
Basic:
Weighted average common shares (in shares)	48,494	47,708	48,485	47,691
Basic earnings per common share (in dollars per share)	$ 1.55	$ 1.15	$ 3.09	$ 2.30
Diluted:
Effect of dilutive stock options (in shares)	984	1,299	1,070	1,250
Diluted weighted average common shares (in shares)	49,478	49,007	49,555	48,941
Diluted earnings per common share (in dollars per share)	$ 1.52	$ 1.12	$ 3.02	$ 2.24