CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (loss)	Retained Earnings	Total
Balance at Aug. 31, 2020	$ 944	$ 16,674	$ (13,092)	$ 298,266	$ 302,792
Balance (in shares) at Aug. 31, 2020	9,439,082
Increase (Decrease) in Stockholders' Equity
Restricted stock grants, net of forfeitures	$ 2	(2)
Restricted stock grants, net of forfeitures (in shares)	10,693
Amortization of restricted stock grants		1,789			1,789
Amortization of stock option grants		420			420
Exercise of stock options		207			207
Exercise of stock options (in shares)	4,681
Common stock received for payment of stock option exercises		(121)			(121)
Common stock received for payment of stock option exercises (in shares)	(1,075)
Common stock retained to pay statutory minimum withholding taxes on common stock		(371)			(371)
Common stock retained to pay statutory minimum withholding taxes on common stock (in shares)	(3,595)
Cash dividend on common stock				(7,557)	(7,557)
Change in funded status of pension plans, net of tax			371		371
Foreign currency translation adjustment			3,273		3,273
Net unrealized gain (loss) on restricted investments, net of tax			186		186
Net income				34,297	34,297
Balance at May. 31, 2021	$ 946	18,596	(9,262)	325,006	335,286
Balance (in shares) at May. 31, 2021	9,449,786
Balance at Feb. 28, 2021	$ 946	17,721	(10,840)	310,717	318,544
Balance (in shares) at Feb. 28, 2021	9,448,371
Increase (Decrease) in Stockholders' Equity
Amortization of restricted stock grants		600			600
Amortization of stock option grants		195			195
Exercise of stock options		166			166
Exercise of stock options (in shares)	2,149
Common stock received for payment of stock option exercises		(80)			(80)
Common stock received for payment of stock option exercises (in shares)	(689)
Common stock retained to pay statutory minimum withholding taxes on common stock		(6)			(6)
Common stock retained to pay statutory minimum withholding taxes on common stock (in shares)	(45)
Change in funded status of pension plans, net of tax			124		124
Foreign currency translation adjustment			1,386		1,386
Net unrealized gain (loss) on restricted investments, net of tax			68		68
Net income				14,289	14,289
Balance at May. 31, 2021	$ 946	18,596	(9,262)	325,006	335,286
Balance (in shares) at May. 31, 2021	9,449,786
Balance at Aug. 31, 2021	$ 946	18,959	(11,210)	335,629	344,324
Balance (in shares) at Aug. 31, 2021	9,447,905
Increase (Decrease) in Stockholders' Equity
Restricted stock grants, net of forfeitures	$ 2	(2)
Restricted stock grants, net of forfeitures (in shares)	20,685
Amortization of restricted stock grants		1,721			1,721
Amortization of stock option grants		697			697
Cash dividend on common stock				(9,460)	(9,460)
Change in funded status of pension plans, net of tax			336		336
Foreign currency translation adjustment			(5,174)		(5,174)
Net unrealized gain (loss) on restricted investments, net of tax			(277)		(277)
Net income				34,398	34,398
Balance at May. 31, 2022	$ 948	21,375	(16,325)	360,567	366,565
Balance (in shares) at May. 31, 2022	9,468,590
Balance at Feb. 28, 2022	$ 948	20,513	(13,209)	345,022	353,274
Balance (in shares) at Feb. 28, 2022	9,468,888
Increase (Decrease) in Stockholders' Equity
Restricted stock grants, net of forfeitures (in shares)	(298)
Amortization of restricted stock grants		613			613
Amortization of stock option grants		249			249
Change in funded status of pension plans, net of tax			112		112
Foreign currency translation adjustment			(3,116)		(3,116)
Net unrealized gain (loss) on restricted investments, net of tax			(112)		(112)
Net income				15,545	15,545
Balance at May. 31, 2022	$ 948	$ 21,375	$ (16,325)	$ 360,567	$ 366,565
Balance (in shares) at May. 31, 2022	9,468,590