Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Aug. 31, 2020	Aug. 31, 2019
Current assets:
Allowance for doubtful accounts	$ 2.6	$ 1.0
Stockholders’ equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, issued (in shares)	53,885,165	53,778,155
Treasury stock (in shares)	15,012,449	14,325,197