Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Capital In Excess Of Stated Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss, Net [Member]
Beginning balance, value at Aug. 31, 2020	$ 298,518	$ 18,918	$ (277,238)	$ 77,686	$ 499,724	$ (20,572)
Beginning balance, shares at Aug. 31, 2020		18,918	8,083
Net earnings	7,095	$ 0	$ 0	0	7,095	0
Other comprehensive income (loss)	1,395	0	0	0	0	1,395
Total comprehensive income	8,490	0	0	0	0	0
Cash dividends per share	(3,477)	0	0	0	(3,477)	0
Issuance of common shares under share compensation plans, net	(1,213)	$ 30	$ 0	(1,243)	0	0
Issuance of common shares under share compensation plans, net, shares		30	0
Share-based compensation expense	1,583	$ 0	$ 0	1,583	0	0
Ending balance, value at Nov. 30, 2020	303,901	$ 18,948	$ (277,238)	78,026	503,342	(19,177)
Ending Balance, shares at Nov. 30, 2020		18,948	8,083
Beginning balance, value at Aug. 31, 2021	338,445	$ 18,991	$ (277,238)	86,495	528,130	(17,933)
Beginning balance, shares at Aug. 31, 2021		18,991	8,083
Net earnings	7,901	$ 0	$ 0	0	7,901	0
Other comprehensive income (loss)	(3,358)	0	0	0	0	(3,358)
Total comprehensive income	4,543	0	0	0	0	0
Cash dividends per share	(3,621)	0	0	0	(3,621)	0
Issuance of common shares under share compensation plans, net	1,354	$ 65	$ 0	1,289	0	0
Issuance of common shares under share compensation plans, net, shares		65	0
Share-based compensation expense	1,222	$ 0	$ 0	1,222	0	0
Ending balance, value at Nov. 30, 2021	$ 341,943	$ 19,056	$ (277,238)	$ 89,006	$ 532,410	$ (21,291)
Ending Balance, shares at Nov. 30, 2021		19,056	8,083