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	669	$ 0	$ 0	0	669	0
Other comprehensive income (loss)	229	0	0	0	0	229
Total comprehensive income	898	0	0	0	0	0
Cash dividends per share	(10,032)	0	0	0	(10,032)	0
Issuance of common shares under share compensation plans, net, value	(947)	$ 29	$ 0	(976)	0	0
Issuance of common shares under share compensation plans, net, shares		29	0
Share-based compensation expense	3,077	$ 0	$ 0	3,077	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 May. 31, 2019	270,394	$ 18,870	$ (277,238)	70,566	476,580	(18,384)
Ending Balance, shares at May. 31, 2019		18,870	8,083
Beginning balance, value at Feb. 28, 2019	271,840	$ 18,870	$ (277,238)	69,772	477,027	(16,591)
Beginning balance, shares at Feb. 28, 2019		18,870	8,083
Net earnings	2,897	$ 0	$ 0	0	2,897	0
Other comprehensive income (loss)	(1,793)	0	0	0	0	(1,793)
Total comprehensive income	1,104	0	0	0	0	0
Cash dividends per share	(3,344)	0	0	0	(3,344)	0
Share-based compensation expense	794	0	0	794	0	0
Ending balance, value at May. 31, 2019	270,394	$ 18,870	$ (277,238)	70,566	476,580	(18,384)
Ending Balance, shares at May. 31, 2019		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	23,955	$ 0	$ 0	0	23,955	0
Other comprehensive income (loss)	(3,581)	0	0	0	0	(3,581)
Total comprehensive income	20,374	0	0	0	0	0
Cash dividends per share	(10,177)	0	0	0	(10,177)	0
Issuance of common shares under share compensation plans, net, value	434	$ 48	$ 0	386	0	0
Issuance of common shares under share compensation plans, net, shares		48	0
Share-based compensation expense	4,118	$ 0	$ 0	4,118	0	0
Ending balance, value at May. 31, 2020	282,958	$ 18,918	$ (277,238)	76,188	488,518	(23,428)
Ending Balance, shares at May. 31, 2020		18,918	8,083
Beginning balance, value at Feb. 29, 2020	277,327	$ 18,918	$ (277,238)	74,645	481,890	(20,888)
Beginning balance, shares at Feb. 29, 2020		18,918	8,083
Net earnings	10,094	$ 0	$ 0	0	10,094	0
Other comprehensive income (loss)	(2,540)	0	0	0	0	(2,540)
Total comprehensive income	7,554	0	0	0	0	0
Cash dividends per share	(3,466)	0	0	0	(3,466)	0
Share-based compensation expense	1,543	0	0	1,543	0	0
Ending balance, value at May. 31, 2020	$ 282,958	$ 18,918	$ (277,238)	$ 76,188	$ 488,518	$ (23,428)
Ending Balance, shares at May. 31, 2020		18,918	8,083

Cumulative effects adjustment from adoption of new accounting standards.

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Amount of increase to additional paid-in capital (APIC) for recognition of cost for award under share-based payment arrangement.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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