Quarterly Financial Data (unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Net sales	$ 369,654,000	$ 368,706,000	$ 385,559,000	$ 373,696,000	$ 408,167,000	$ 395,628,000	$ 327,360,000	$ 224,722,000	$ 1,497,615,000	$ 1,355,877,000	$ 901,608,000
Gross profit	6,131,000	103,355,000	109,086,000	105,923,000	113,638,000	115,972,000	96,560,000	76,830,000	324,495,000	403,000,000	317,648,000
Net (loss) income	$ (213,999,000)	$ 16,479,000	$ 23,046,000	$ 19,730,000	$ 24,647,000	$ 28,772,000	$ 24,312,000	$ 24,370,000	$ (154,744,000)	$ 102,102,000	$ 104,812,000
Basic net income per share (in dollars per share)	$ (2.21)	$ 0.17	$ 0.24	$ 0.20	$ 0.25	$ 0.30	$ 0.25	$ 0.26	$ (1.60)	$ 1.06	$ 1.12
Diluted net income per share (in dollars per share)	$ (2.21)	$ 0.17	$ 0.24	$ 0.20	$ 0.25	$ 0.29	$ 0.25	$ 0.25	$ (1.60)	$ 1.05	$ 1.09
Goodwill impairment charge	$ 263,771,000								$ 263,771,000
Increase in inventory reserve	264,114,000				$ 197,188,000				264,114,000	$ 197,188,000
Lack of marketability for inventory specific to one program
Increase in inventory reserve	33,000,000								33,000,000
Total of all the actions that affected Inventory Reserve
Increase in inventory reserve	$ 83,400,000								$ 83,400,000
Revised E&O reserve
Increase in inventory reserve					$ 143,736,000					$ 143,736,000