Industry Segment Information (Schedule of Segment Reporting Information Impacts on Balance Sheet, by Segment) (Details) - USD ($) $ in Thousands	May 31, 2020	Aug. 31, 2019	May 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 557,486	$ 500,314	$ 505,922
Irrigation [Member]
Segment Reporting Information [Line Items]
Total assets	313,216	292,202	306,714
Infrastructure [Member]
Segment Reporting Information [Line Items]
Total assets	105,832	85,848	80,971
Corporate Segment
Segment Reporting Information [Line Items]
Total assets	$ 138,438	$ 122,264	$ 118,237

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Name:	us-gaap_Assets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant