Property, Plant, and Equipment, Net (Property, Plant, and Equipment - Net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Property, Plant, and Equipment, Net
Land and Land Improvements	$ 88,326	$ 87,696
Buildings and improvements	514,453	527,704
Leasehold improvements	16,142	15,213
Machinery and production equipment	543,641	484,315
Computer equipment and software	124,723	117,984
Office furniture and equipment	24,308	29,344
Other	19,393	18,969
Construction in progress	111,910	88,909
Property, Plant and Equipment, Gross, Total	1,442,896	1,370,134
Less accumulated depreciation	(520,853)	(493,784)
Property, Plant and Equipment, Net, Total	922,043	876,350
Depreciation expense	55,140	41,550	$ 45,994
Capitalized interest	$ 2,008	$ 5,455	$ 8,995