Net Earnings Per Share (Schedule Of Computation Of Basic And Diluted Net Earnings Per Share)(Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Net Earnings Per Share [Abstract]
Net earnings	$ 12,927	$ 16,499	$ 29,490	$ 40,183
Weighted average shares outstanding	11,690	12,843	11,965	12,881
Diluted effect of stock awards	30	46	35	46
Weighted average shares outstanding assuming dilution	11,720	12,889	12,000	12,927
Basic net earnings per share	$ 1.11	$ 1.28	$ 2.46	$ 3.12
Diluted net earnings per share	$ 1.10	$ 1.28	$ 2.46	$ 3.11