Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Nov. 30, 2014		Nov. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 10,085		$ 8,208
Weighted average common shares outstanding – basic	53,360		56,292
Effect of dilutive employee stock options and unvested restricted stock units	1,467		1,605
Weighted average common shares - diluted	54,827		57,897
Net income per common share - basic	$ 0.19		$ 0.15
Net income per common share - diluted	$ 0.18		$ 0.14
Anti-dilutive securities excluded	455	[1]	967	[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.