Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2025	May 31, 2024	May 31, 2025	May 31, 2024
Income Statement [Abstract]
Operating revenues	$ 169,464	$ 139,199	$ 522,809	$ 452,076
Cost of operating revenues	115,842	92,702	356,734	306,720
Gross profit	53,622	46,497	166,075	145,356
Operating expenses:
Selling expense	10,217	9,579	31,278	28,894
General and administrative expense	14,903	12,695	45,263	40,823
Engineering and research expense	4,709	4,287	12,735	12,531
Total operating expenses	29,829	26,561	89,276	82,248
Operating income	23,793	19,936	76,799	63,108
Other income (expense):
Interest expense	(345)	(767)	(1,498)	(2,474)
Interest income	2,242	961	5,330	3,324
Other income (expense), net	24	43	330	(93)
Total other income (expense)	1,921	237	4,162	757
Earnings before income taxes	25,714	20,173	80,961	63,865
Income tax expense (benefit)	6,214	(206)	17,722	10,344
Net earnings	$ 19,500	$ 20,379	$ 63,239	$ 53,521
Earnings per share:
Basic	$ 1.80	$ 1.85	$ 5.82	$ 4.86
Diluted	$ 1.78	$ 1.85	$ 5.79	$ 4.84
Shares used in computing earnings per share:
Basic	10,862	10,996	10,860	11,016
Diluted	10,931	11,030	10,915	11,055
Cash dividends declared per share	$ 0.36	$ 0.35	$ 1.08	$ 1.05