Earnings Per Share (Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Feb. 29, 2012		Feb. 28, 2011		Feb. 29, 2012		Feb. 28, 2011
Earnings Per Share [Abstract]
Net income	$ 1,677		$ 4,348		$ 7,176		$ 11,590
Weighted average common shares outstanding - basic	60,579		61,687		61,136		61,663
Effect of dilutive employee stock options and unvested restricted stock units	23		178		34		146
Weighted average common shares - diluted	60,602		61,865		61,170		61,809
Net income per common share - basic	$ 0.03		$ 0.07		$ 0.12		$ 0.19
Net income per common share - diluted	$ 0.03		$ 0.07		$ 0.12		$ 0.19
Anti-dilutive securities excluded	7,279	[1]	6,363	[1]	7,212	[1]	6,703	[1]

[1] Anti-dilutive securities consist of stock options and unvested restricted stock units that were not included in the computation of diluted earnings per share because either the exercise price of the options was greater than the average market price of the common stock or the total assumed proceeds under the treasury stock method resulted in negative incremental shares and thus the inclusion would have been anti-dilutive.