Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Income Statement [Abstract]
Operating revenues	$ 151,519	$ 166,241	$ 312,877	$ 342,400
Cost of operating revenues	102,565	111,983	214,018	235,122
Gross profit	48,954	54,258	98,859	107,278
Operating expenses:
Selling expense	9,498	8,733	19,315	18,410
General and administrative expense	13,466	13,739	28,128	28,176
Engineering and research expense	3,892	4,521	8,244	8,829
Total operating expenses	26,856	26,993	55,687	55,415
Operating income	22,098	27,265	43,172	51,863
Other income (expense):
Interest expense	(830)	(1,038)	(1,707)	(1,947)
Interest income	1,295	490	2,363	865
Other income (expense), net	134	(984)	(136)	(1,043)
Total other income (expense)	599	(1,532)	520	(2,125)
Earnings before income taxes	22,697	25,733	43,692	49,738
Income tax expense	4,574	7,681	10,550	13,469
Net earnings	$ 18,123	$ 18,052	$ 33,142	$ 36,269
Earnings per share:
Basic	$ 1.64	$ 1.64	$ 3.01	$ 3.3
Diluted	$ 1.64	$ 1.63	$ 2.99	$ 3.28
Shares used in computing earnings per share:
Basic	11,033	11,007	11,025	10,998
Diluted	11,074	11,063	11,067	11,068
Cash dividends declared per share	$ 0.35	$ 0.34	$ 0.7	$ 0.68