Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Nov. 30, 2021	Aug. 31, 2021	Nov. 30, 2020
Statement of Financial Position [Abstract]
Receivables, allowance	$ 3,398	$ 3,422	$ 2,960
Preferred stock, par value	$ 1	$ 1	$ 1
Preferred stock, authorized	2,000,000	2,000,000	2,000,000
Preferred stock, issued	0	0	0
Preferred stock, outstanding	0	0	0
Common stock, par value	$ 1	$ 1	$ 1
Common stock, authorized	25,000,000	25,000,000	25,000,000
Common stock, issued	19,056,000	18,991,000	18,948,000
Treasury stock, shares	8,083,000	8,083,000	8,083,000