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								12 Months Ended
	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Net Earnings Per Share [Abstract]
Net earnings	$ 6,342	$ 10,952	$ 5,012	$ 873	$ 7,808	$ 9,644	$ (4,129)	$ 6,944	$ 23,179	$ 20,267	$ 26,309
Weighted average shares outstanding									10,666	10,906	11,818
Diluted effect of stock equivalents									28	24	37
Weighted average shares outstanding assuming dilution									10,694	10,930	11,855
Basic net earnings per share									$ 2.17	$ 1.86	$ 2.23
Diluted net earnings per share	$ 0.59	$ 1.02	$ 0.47	$ 0.08	$ 0.73	$ 0.90	$ (0.37)	$ 0.62	$ 2.17	$ 1.85	$ 2.22