Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Nov. 30, 2016	Nov. 30, 2015
Earnings Per Share [Abstract]
Net income	$ 13,118	$ 12,458
Weighted average common shares outstanding– basic (in shares)	45,720	50,221
Effect of dilutive employee stock options and unvested restricted stock units (in shares)	823	1,104
Weighted average common shares outstanding – diluted (in shares)	46,543	51,325
Net income per common share – basic (usd per share)	$ 0.29	$ 0.25
Net income per common share – diluted (usd per share)	$ 0.28	$ 0.24
Anti-dilutive securities excluded (in shares)	821	412