Earnings Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2010
Earnings Per Share Reconciliation Of Basic And Diluted
Net Income	$ (1,959,000)	$ (4,613,000)	$ 50,192,000	$ 76,227,000	$ (9,577,000)	$ (8,703,000)	$ 47,408,000	$ 84,440,000	$ 119,847,000	$ 113,568,000	$ 141,954,000
Average shares of common stock outstanding for basic earnings per share									71,977,000	72,056,000	72,275,000
Contingently Issuable Shares Under the Executive Long Term Incentive Plan And Incentive Compensation Plan									301,000	210,000	250,000
Average shares of dilutive stock									72,278,000	72,266,000	72,525,000
Earnings Per Share of Common Stock
Basic EPS	$ (0.03)	$ (0.06)	$ 0.70	$ 1.06	$ (0.13)	$ (0.12)	$ 0.66	$ 1.17	$ 1.67	$ 1.58	$ 1.96
Diluted EPS	$ (0.03)	$ (0.06)	$ 0.70	$ 1.05	$ (0.13)	$ (0.12)	$ 0.66	$ 1.16	$ 1.66	$ 1.57	$ 1.96