Property, Plant, and Equipment, Net (Property, Plant, and Equipment - Net) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Sep. 30, 2013
Property, Plant, and Equipment, Net
Land and Land Improvements	$ 57,540		$ 57,540		$ 57,562
Buildings and improvements	199,314		199,314		195,008
Leasehold improvements	20,682		20,682		18,924
Machinery and production equipment	320,319		320,319		305,692
Computer equipment and software	101,726		101,726		97,538
Office furniture and equipment	24,399		24,399		24,400
Other	18,849		18,849		14,197
Construction in progress	125,761		125,761		81,428
Property, Plant and Equipment, Gross, Total	868,590		868,590		794,749
Less accumulated depreciation	(467,540)		(467,540)		(444,701)
Property, Plant and Equipment, Net, Total	401,050		401,050		350,048
Depreciation expense	11,062	10,139	21,694	20,412
Capitalized interest	$ 1,314	$ 88	$ 2,289	$ 188