Segment Information (Property, Plant, and Equipment - Net by Geographical Area) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 1,060,005	$ 922,043
United States [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	922,734	872,947
Germany [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	111,595	24,541
Other Countries [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 25,676	$ 24,555