Inventories (Schedule of Major Classes of Inventory) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 86,469	$ 78,319
Work in progress	19,842	15,654
Finished goods and products held for resale	59,624	56,435
Costs of unbilled projects	2,277	3,438
Reserves for excess and obsolete	(9,709)	(11,467)
Inventory, Net	$ 158,503	$ 142,379