Industry Segment Information (Reconciliation Of Assets From Segment To Consolidated) (Details) - USD ($) $ in Thousands	May 31, 2016	Aug. 31, 2015	May 31, 2015
Segment Reporting Information [Line Items]
Total Assets	$ 501,705	$ 536,468	$ 577,894
Irrigation [Member]
Segment Reporting Information [Line Items]
Total Assets	394,739	429,224	447,988
Infrastructure [Member]
Segment Reporting Information [Line Items]
Total Assets	$ 106,966	$ 107,244	$ 129,906