| **Long-Term Debt (Tables)**                           | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
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| **Long-term Debt, Other Disclosures [Abstract]**      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Schedule Of Long-Term Debt                            | 4.Long-Term DebtLong-term debt as of April 30, 2013, July 31, 2012 and April 30, 2012 is summarized as follows (in thousands):   Maturity (a) April 30, 2013 July 31, 2012 April 30, 2012Credit Facility Revolver 2016 $— $— $—Industrial Development Bonds 2020 41,200 41,200 41,200Employee Housing Bonds 2027-2039 52,575 52,575 52,5756.50% Notes  2019 390,000 390,000 390,000Other 2013-2029 5,983 6,990 7,101Total debt   489,758 490,765 490,876Less: Current maturities (b)   518 990 1,119Long-term debt   $489,240 $489,775 $489,757 (a)Maturities are based on the Company’s July 31 fiscal year end.(b)Current maturities represent principal payments due in the next 12 months. |
| Schedule Of Aggregate Maturities For Debt Outstanding | Aggregate maturities for debt outstanding as of April 30, 2013 reflected by fiscal year are as follows (in thousands):   2013$92014509201553320162442017257Thereafter488,206  Total debt$489,758                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |

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| - Definition
Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.
+ References
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| - Definition
Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented.
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