Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Feb. 28, 2014		Feb. 28, 2013		Feb. 28, 2014		Feb. 28, 2013
Earnings Per Share [Abstract]
Net income	$ 4,107		$ 3,577		$ 12,315		$ 9,710
Weighted average common shares outstanding – basic	55,958		55,798		56,125		56,735
Effect of dilutive employee stock options and unvested restricted stock units	1,450		625		1,528		519
Weighted average common shares - diluted	57,408		56,423		57,653		57,254
Net income per common share - basic	$ 0.07		$ 0.06		$ 0.22		$ 0.17
Net income per common share - diluted	$ 0.07		$ 0.06		$ 0.21		$ 0.17
Anti-dilutive securities excluded	1,117	[1]	3,735	[1]	1,042	[1]	4,151	[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.