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) Income, Net [Member]
Beginning balance, value at Aug. 31, 2018	$ 276,866	$ 18,841	$ (277,238)	$ 68,465	$ 484,886	$ (18,088)
Beginning balance, shares at Aug. 31, 2018		18,841	8,083
Net earnings	1,212	$ 0	$ 0	0	1,212	0
Other comprehensive (loss) income	1,135	0	0	0	0	1,135
Total comprehensive income (loss)	2,347	0	0	0	0	0
Cash dividends ($0.31) per share	(3,344)	0	0	0	(3,344)	0
Issuance of common shares under share compensation plans, net, value	(943)	$ 29	$ 0	(972)	0	0
Issuance of common shares under share compensation plans, net, shares		29	0
Share-based compensation expense	1,217	$ 0	$ 0	1,217	0	0
Cumulative impact of ASC/ASU adoption | ASC 606 [Member]	532	0	0	0	532	0
Cumulative impact of ASC/ASU adoption | ASU 2018-02 [Member]	0	0	0	0	525	(525)
Ending balance, value at Nov. 30, 2018	276,675	$ 18,870	$ (277,238)	68,710	483,811	(17,478)
Ending Balance, shares at Nov. 30, 2018		18,870	8,083
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	8,345	$ 0	$ 0	0	8,345	0
Other comprehensive (loss) income	(250)	0	0	0	0	(250)
Total comprehensive income (loss)	8,095	0	0	0	0	0
Cash dividends ($0.31) per share	(3,353)	0	0	0	(3,353)	0
Issuance of common shares under share compensation plans, net, value	(1,111)	$ 27	$ 0	(1,138)	0	0
Issuance of common shares under share compensation plans, net, shares		27	0
Share-based compensation expense	1,160	$ 0	$ 0	1,160	0	0
Ending balance, value at Nov. 30, 2019	$ 273,000	$ 18,897	$ (277,238)	$ 71,706	$ 479,732	$ (20,097)
Ending Balance, shares at Nov. 30, 2019		18,897	8,083