Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Current federal	$ 0	$ (64)	$ (44,789)
Current state	595	520	322
Deferred federal	5,574	(314,651)	2,385
Deferred state	10,329	(10,374)	285
Total	16,498	(324,569)	$ (41,797)
Income Tax Contingency [Line Items]
Valuation allowances and reserves, adjustments		$ 335,200
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Valuation allowances and reserves, adjustments	$ 8,600