Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Income Statement [Abstract]
Operating revenues	$ 200,137	$ 143,577	$ 366,288	$ 252,062
Cost of operating revenues	157,193	102,403	285,907	179,480
Gross profit	42,944	41,174	80,381	72,582
Operating expenses:
Selling expense	7,932	7,778	15,922	15,110
General and administrative expense	13,022	14,275	25,901	27,727
Engineering and research expense	3,652	3,312	6,859	6,402
Total operating expenses	24,606	25,365	48,682	49,239
Operating income	18,338	15,809	31,699	23,343
Other income (expense):
Interest expense	(1,176)	(1,205)	(2,339)	(2,406)
Interest income	160	268	338	571
Other income (expense), net	1,882	(311)	(1,018)	(65)
Total other income (expense)	866	(1,248)	(3,019)	(1,900)
Earnings before income taxes	19,204	14,561	28,680	21,443
Income tax expense	4,638	2,685	6,213	2,472
Net earnings	$ 14,566	$ 11,876	$ 22,467	$ 18,971
Earnings per share:
Basic	$ 1.33	$ 1.09	$ 2.05	$ 1.75
Diluted	$ 1.32	$ 1.08	$ 2.04	$ 1.74
Shares used in computing earnings per share:
Basic	10,974	10,884	10,950	10,865
Diluted	11,014	10,981	11,020	10,934
Cash dividends declared per share	$ 0.33	$ 0.32	$ 0.66	$ 0.64