| **Stock Repurchase Plan**                        | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
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| **Payments for Repurchase of Equity [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Stock Repurchase Plan                            | Stock Repurchase PlanOn March 9, 2006, the Company’s Board of Directors approved the repurchase of up to 3,000,000 shares of common stock and on July 16, 2008 approved an increase of the Company’s common stock repurchase authorization by an additional 3,000,000 shares. During the year ended July 31, 2012, the Company repurchased 684,307 shares of common stock. Since inception of this stock repurchase program through July 31, 2012, the Company has repurchased 4,949,111 shares at a cost of approximately $193.2 million. As of July 31, 2012, 1,050,889 shares remained available to repurchase under the existing repurchase authorization. Shares of common stock purchased pursuant to the repurchase program will be held as treasury shares and may be used for issuance under the Company’s employee share award plan. |

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| - Definition
Tabular disclosure of an entity's treasury stock, including the average cost per share, carrying basis for each class of treasury stock, description of share repurchase program authorized by an entity's board of directors, the number of shares repurchased, the cost of the shares repurchased, the remaining maximum dollar value of shares available for repurchase under the program, the treatment of the purchase price in excess of the current market value, number of shares held for each class of treasury stock, and other information necessary to a fair presentation.
+ References
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