Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data	May 31, 2011	Aug. 31, 2010
Accounts receivable, allowance for doubtful accounts	$ 6,336	$ 6,209
Preferred stock, shares authorized	20,000	20,000
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares issued	0	0
Class A Common Stock [Member]
Common stock, shares authorized	75,000	75,000
Common stock, par value	$ 1	$ 1
Common stock, shares issued	24,255	22,700
Common stock, shares outstanding	24,255	22,700
Class B Common Stock [Member]
Common stock, shares authorized	25,000	25,000
Common stock, par value	$ 1	$ 1
Common stock, shares issued	3,237	4,721
Common stock, shares outstanding	3,237	4,721