Inventories (Schedule of Inventories) (Details) - USD ($) $ in Thousands	May 31, 2020	Aug. 31, 2019	May 31, 2019
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 50,820	$ 49,047	$ 44,742
Work in process	7,819	4,514	6,917
Finished goods and purchased parts, net	59,496	46,812	47,659
Total inventory value before LIFO adjustment	118,135	100,373	99,318
Less adjustment to LIFO value	(4,834)	(8,086)	(8,227)
Inventories, net	$ 113,301	$ 92,287	$ 91,091