Long-Term Debt (Schedule Of Debt Instruments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended			12 Months Ended						12 Months Ended						3 Months Ended
	Oct. 31, 2012	Jul. 31, 2012	Oct. 31, 2011	Jul. 31, 2012 Credit Facility Revolver [Member]	Oct. 31, 2012 Credit Facility Revolver [Member]	Oct. 31, 2011 Credit Facility Revolver [Member]	Jul. 31, 2012 Industrial Development Bonds [Member]	Oct. 31, 2012 Industrial Development Bonds [Member]	Oct. 31, 2011 Industrial Development Bonds [Member]	Oct. 31, 2012 Employee Housing Bonds [Member]	Jul. 31, 2012 Employee Housing Bonds [Member]	Oct. 31, 2011 Employee Housing Bonds [Member]	Jul. 31, 2012 6.50% Notes [Member]	Oct. 31, 2012 6.50% Notes [Member]	Oct. 31, 2011 6.50% Notes [Member]	Oct. 31, 2012 Other [Member]	Jul. 31, 2012 Other [Member]	Oct. 31, 2011 Other [Member]	Oct. 31, 2012 Maximum [Member] Employee Housing Bonds [Member]	Oct. 31, 2012 Maximum [Member] Other [Member]	Oct. 31, 2012 Minimum [Member] Employee Housing Bonds [Member]	Oct. 31, 2012 Minimum [Member] Other [Member]
Total debt	$ 490,373	$ 490,765	$ 491,440	$ 0	$ 0	$ 0	$ 41,200	$ 41,200	$ 41,200	$ 52,575	$ 52,575	$ 52,575	$ 390,000	$ 390,000	$ 390,000	$ 6,598	$ 6,990	$ 7,665
Less: Current maturities	848	990	1,063
Long-term debt	$ 489,525	$ 489,775	$ 490,377					$ 41,200						$ 390,000
Fiscal year maturity	2019			2016			2020						2019
Fiscal year maturity, start																					Jun. 01, 2027	Jul. 31, 2013
Fiscal year maturity, end																			May 01, 2039	Jul. 31, 2029
Stated percentage in the debt instrument	6.50%													6.50%
Long term debt interest rate													6.50%