Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Nov. 30, 2020	Nov. 30, 2019
Income Statement [Abstract]
Operating revenues	$ 108,485	$ 109,393
Cost of operating revenues	77,077	75,319
Gross profit	31,408	34,074
Operating expenses:
Selling expense	7,331	6,492
General and administrative expense	13,452	11,804
Engineering and research expense	3,090	3,502
Total operating expenses	23,873	21,798
Operating income	7,535	12,276
Other (expense) income:
Interest expense	(1,201)	(1,186)
Interest income	303	615
Other income (expense), net	246	(450)
Total other (expense) income	(652)	(1,021)
Earnings before income taxes	6,883	11,255
Income tax (benefit) expense	(212)	2,910
Net earnings	$ 7,095	$ 8,345
Earnings per share:
Basic	$ 0.65	$ 0.77
Diluted	$ 0.65	$ 0.77
Shares used in computing earnings per share:
Basic	10,845	10,795
Diluted	10,888	10,828
Cash dividends declared per share	$ 0.32	$ 0.31