Property, Plant, and Equipment, Net (Property, Plant, and Equipment - Net) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Property, Plant, and Equipment, Net
Land and Land Improvements	$ 87,930		$ 87,930		$ 87,696
Buildings and improvements	528,735		528,735		527,704
Leasehold improvements	15,635		15,635		15,213
Machinery and production equipment	529,980		529,980		484,315
Computer equipment and software	123,851		123,851		117,984
Office furniture and equipment	26,950		26,950		29,344
Other	19,233		19,233		18,969
Construction in progress	95,074		95,074		88,909
Property, Plant and Equipment, Gross, Total	1,427,388		1,427,388		1,370,134
Less accumulated depreciation	(523,994)		(523,994)		(493,784)
Property, Plant and Equipment, Net, Total	903,394		903,394		$ 876,350
Depreciation expense	14,141	$ 10,413	40,259	$ 29,162
Capitalized interest	$ 567	$ 914	$ 1,521	$ 5,054