Industry Segment Information (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019
Segment Reporting Information [Line Items]
Total operating revenues	$ 567,646	$ 474,692	$ 444,072
Total operating income	54,107	54,202	6,115
Total other (expense) income	(3,721)	(5,359)	(4,008)
Earnings before income taxes	50,386	48,843	2,107
Capital expenditures	26,511	21,445	23,211
Depreciation and amortization	19,177	19,396	14,018
Irrigation [Member]
Segment Reporting Information [Line Items]
Total operating revenues	471,358	349,346	358,548
Total operating income	63,181	41,263	29,374
Capital expenditures	19,188	9,254	9,473
Depreciation and amortization	12,245	12,906	9,500
Irrigation [Member] | North America [Member]
Segment Reporting Information [Line Items]
Total operating revenues	273,871	224,771	225,677
Irrigation [Member] | International [Member]
Segment Reporting Information [Line Items]
Total operating revenues	197,487	124,575	132,871
Infrastructure [Member]
Segment Reporting Information [Line Items]
Total operating revenues	96,288	125,346	85,524
Total operating income	20,174	42,722	17,029
Capital expenditures	6,866	11,275	4,928
Depreciation and amortization	3,748	3,495	3,663
Corporate Segment
Segment Reporting Information [Line Items]
Total operating income	(29,248)	(29,783)	(40,288)
Capital expenditures	457	916	8,810
Depreciation and amortization	$ 3,183	$ 2,994	$ 855