Property, Plant, and Equipment (Schedule of Property Plant and Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 1,664,798	$ 1,651,390
Less accumulated depreciation	(678,768)	(653,975)
Property, plant, and equipment, net	986,030	997,415
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	83,606	83,095
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	553,274	551,540
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	19,577	18,610
Machinery and Production Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	786,343	776,884
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	124,290	123,903
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	41,825	41,177
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	19,849	19,814
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 36,034	$ 36,367