Net Earnings Per Share	3 Months Ended
Nov. 30, 2011
Net Earnings Per Share [Abstract]
Net Earnings Per Share	(2) Net Earnings per Share Basic net earnings per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net earnings per share is computed using the weighted-average number of common shares outstanding plus dilutive potential common shares outstanding during the period. Dilutive potential common shares consist of stock options and restricted stock units to the extent they are not anti-dilutive. Performance stock units are excluded from the calculation of dilutive potential common shares until the threshold performance conditions have been satisfied. At November 30, 2011, the threshold performance conditions for the Company's outstanding performance stock units that were granted on November 12, 2009, November 1, 2010 and October 31, 2011 had not been satisfied, resulting in the exclusion of 89,374 performance stock units from the calculation of diluted net earnings per share. Employee stock options, nonvested shares and similar equity instruments granted by the Company are treated as potential common share equivalents outstanding in computing diluted net earnings per share. The Company's diluted common shares outstanding reported in each period includes the dilutive effect of restricted stock units, in-the-money options, and performance stock units for which threshold performance conditions have been satisfied and is calculated based on the average share price for each fiscal period using the treasury stock method. Under the treasury stock method, the amount the employee must pay for exercising stock options, the amount of compensation cost for future service that the Company has not yet recognized on share based awards, and the amount of excess tax benefits that would be recorded in additional paid-in capital when shares are issued and assumed to be used to repurchase shares. There were 10,846 and 8,249 restricted stock units excluded from the calculation of diluted net earnings per share for the three months ended November 30, 2011 and 2010 since their inclusion would have been anti-dilutive. In addition, there were 12,364 stock options excluded from the calculation of diluted net earnings per share for the three months ended November 30, 2011 because they had an exercise price exceeding the average market price of the Company's common shares during the period.

(2) Net Earnings per Share

Basic net earnings per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net earnings per share is computed using the weighted-average number of common shares outstanding plus dilutive potential common shares outstanding during the period. Dilutive potential common shares consist of stock options and restricted stock units to the extent they are not anti-dilutive. Performance stock units are excluded from the calculation of dilutive potential common shares until the threshold performance conditions have been satisfied. At November 30, 2011, the threshold performance conditions for the Company's outstanding performance stock units that were granted on November 12, 2009, November 1, 2010 and October 31, 2011 had not been satisfied, resulting in the exclusion of 89,374 performance stock units from the calculation of diluted net earnings per share.

Employee stock options, nonvested shares and similar equity instruments granted by the Company are treated as potential common share equivalents outstanding in computing diluted net earnings per share. The Company's diluted common shares outstanding reported in each period includes the dilutive effect of restricted stock units, in-the-money options, and performance stock units for which threshold performance conditions have been satisfied and is calculated based on the average share price for each fiscal period using the treasury stock method. Under the treasury stock method, the amount the employee must pay for exercising stock options, the amount of compensation cost for future service that the Company has not yet recognized on share based awards, and the amount of excess tax benefits that would be recorded in additional paid-in capital when shares are issued and assumed to be used to repurchase shares.

There were 10,846 and 8,249 restricted stock units excluded from the calculation of diluted net earnings per share for the three months ended November 30, 2011 and 2010 since their inclusion would have been anti-dilutive. In addition, there were 12,364 stock options excluded from the calculation of diluted net earnings per share for the three months ended November 30, 2011 because they had an exercise price exceeding the average market price of the Company's common shares during the period.