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, 2019	$ 268,209	$ 18,870	$ (277,238)	$ 71,684	$ 474,740	$ (19,847)
Beginning balance, shares at Aug. 31, 2019		18,870	8,083
Net earnings	38,629				38,629
Other comprehensive income (loss)	(725)					(725)
Total comprehensive income	37,904
Cash dividends per share	(13,645)				(13,645)
Issuance of common shares under share compensation plans, net	434	$ 48		386
Issuance of common shares under share compensation plans, net, shares		48
Share-based compensation expense	5,616			5,616
Ending balance, value at Aug. 31, 2020	298,518	$ 18,918	$ (277,238)	77,686	499,724	(20,572)
Ending Balance, shares at Aug. 31, 2020		18,918	8,083
Net earnings	42,572				42,572
Other comprehensive income (loss)	2,639					2,639
Total comprehensive income	45,211
Cash dividends per share	(14,166)				(14,166)
Issuance of common shares under share compensation plans, net	2,696	$ 73		2,623
Issuance of common shares under share compensation plans, net, shares		73
Share-based compensation expense	6,186			6,186
Ending balance, value at Aug. 31, 2021	338,445	$ 18,991	$ (277,238)	86,495	528,130	(17,933)
Ending Balance, shares at Aug. 31, 2021		18,991	8,083
Net earnings	65,469				65,469
Other comprehensive income (loss)	(3,540)					(3,540)
Total comprehensive income	61,929
Cash dividends per share	(14,599)				(14,599)
Issuance of common shares under share compensation plans, net	2,125	$ 72		2,053
Issuance of common shares under share compensation plans, net, shares		72
Share-based compensation expense	5,458			5,458
Ending balance, value at Aug. 31, 2022	$ 393,358	$ 19,063	$ (277,238)	$ 94,006	$ 579,000	$ (21,473)
Ending Balance, shares at Aug. 31, 2022		19,063	8,083