CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Feb. 28, 2018	Aug. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4,524	$ 4,146
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	129,060,664	129,060,664
Common stock, shares outstanding	116,825,668	115,793,736
Treasury stock, shares	12,234,996	13,266,928