Summarized Data for Each of the Quarters (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	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
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 16,008	$ 19,751	$ 27,942	$ 21,166	$ 26,285	$ 40,728	$ 68,551	$ 101,348	$ 84,867	$ 236,912	$ 300,607
Gross profit (loss)	(9,289)	(3,306)	1,416	(21)	6,089	15,376	27,903	47,091	(11,200)	96,459	139,761
Income (loss) from operations	(21,667)	(12,451)	(8,549)	(9,888)	(3,282)	5,458	15,956	35,667	(52,555)	53,799	101,227
Other income (expense), net	1,180	(489)	584	1,446	10	(129)	11	(148)	2,721	(256)	(134)
Net income (loss)	$ (13,450)	$ (8,564)	$ (5,182)	$ (5,445)	$ (1,833)	$ 3,752	$ 10,816	$ 24,176	$ (32,641)	$ 36,911	$ 69,557
Basic earnings (loss) per share	$ (1.03)	$ (0.66)	$ (0.40)	$ (0.41)	$ (0.14)	$ 0.29	$ 0.83	$ 1.86	$ (2.51)	$ 2.82	$ 5.40
Diluted earnings (loss) per share	$ (1.03)	$ (0.66)	$ (0.40)	$ (0.41)	$ (0.14)	$ 0.29	$ 0.82	$ 1.85	$ (2.51)	$ 2.81	$ 5.38