Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2019	Aug. 31, 2019
Accounts receivable, allowance for doubtful accounts	$ 17,879	$ 17,088
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A treasury stock, at cost, shares	1,274,580	1,248,944
Class A Common Stock [Member]
Common stock, votes per share	one
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	46,468,912	46,277,284
Class B Common Stock [Member]
Common stock, votes per share	ten
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	10,193,348	10,193,348
Common stock, shares outstanding	10,193,348	10,193,348