Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 632,121	$ 459,937	$ 385,607	$ 344,449	$ 632,852	$ 429,438	$ 299,359	$ 265,764	$ 1,822,114	$ 1,627,413	$ 1,463,767
Gross profit	102,406	77,653	59,566	57,582	107,205	76,108	53,913	35,218	297,207	272,444	263,459
Operating income	30,838	16,309	3,030	9,148	36,945	17,696	6,436	(9,490)	59,325	51,587	55,689
Net (loss) income from continuing operations	$ (789)	$ 6,107	$ (1,312)	$ 1,199	$ 354,524	$ 12,221	$ (2,060)	$ (18,086)	$ 5,205	$ 346,599	$ 34,923
Basic EPS from continuing operations (in dollars per share)	$ (0.03)	$ 0.19	$ (0.04)	$ 0.04	$ 11.42	$ 0.46	$ (0.08)	$ (0.68)	$ 0.16	$ 12.54	$ 1.35
Diluted EPS from continuing operations (in dollars per share)	$ (0.03)	$ 0.19	$ (0.04)	$ 0.04	$ 11.16	$ 0.38	$ (0.08)	$ (0.68)	$ 0.16	$ 10.91	$ 1.10
Inventory impairments and abandonments	$ 184	$ 11,917	$ 1,825	$ 1,356	$ 2,860	$ 249	$ 0	$ 0	$ 15,282	$ 3,109	$ 8,307
Loss on extinguishment of debt	$ (11,393)	$ 429	$ (1,631)	$ (828)	$ (80)	$ 0	$ 0	$ 0	$ (13,423)	(80)	$ (19,917)
Valuation allowances and reserves, adjustments										$ 335,200