Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2024	May 31, 2023	May 31, 2024	May 31, 2023
Income Statement [Abstract]
Operating revenues	$ 139,199	$ 164,553	$ 452,076	$ 506,953
Cost of operating revenues	92,702	111,332	306,720	346,454
Gross profit	46,497	53,221	145,356	160,499
Operating expenses:
Selling expense	9,579	8,681	28,894	27,092
General and administrative expense	12,695	13,061	40,823	41,237
Engineering and research expense	4,287	4,522	12,531	13,350
Total operating expenses	26,561	26,264	82,248	81,679
Operating income	19,936	26,957	63,108	78,820
Other income (expense):
Interest expense	(767)	(948)	(2,474)	(2,895)
Interest income	961	680	3,324	1,545
Other income (expense), net	43	(957)	(93)	(2,000)
Total other income (expense)	237	(1,225)	757	(3,350)
Earnings before income taxes	20,173	25,732	63,865	75,470
Income tax (benefit) expense	(206)	8,851	10,344	22,320
Net earnings	$ 20,379	$ 16,881	$ 53,521	$ 53,150
Earnings per share:
Basic	$ 1.85	$ 1.53	$ 4.86	$ 4.83
Diluted	$ 1.85	$ 1.53	$ 4.84	$ 4.8
Shares used in computing earnings per share:
Basic	10,996	11,008	11,016	11,001
Diluted	11,030	11,052	11,055	11,063
Cash dividends declared per share	$ 0.35	$ 0.34	$ 1.05	$ 1.02