Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Aug. 31, 2020	Aug. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable, reserves	$ 7,987	$ 10,511
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	150,000,000	150,000,000
Common stock, issued (in shares)	40,767,708	40,104,192
Common stock, outstanding (in shares)	38,030,252	38,117,840
Treasury stock (in shares)	2,737,456	1,986,352