Net Earnings Per Share (Schedule Of Computation Of Basic And Diluted Net Earnings Per Share)(Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2015	Feb. 28, 2014
Net Earnings Per Share [Abstract]
Net earnings	$ 8,995	$ 13,450	$ 16,563	$ 23,684
Weighted average shares outstanding	11,982	12,910	12,103	12,899
Diluted effect of stock awards	26	32	38	48
Weighted average shares outstanding assuming dilution	12,008	12,942	12,141	12,947
Basic net earnings per share	$ 0.75	$ 1.04	$ 1.37	$ 1.84
Diluted net earnings per share	$ 0.75	$ 1.04	$ 1.36	$ 1.83