Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Estimated Annual Effective Tax Rate Used to Calculate Income Tax Expense (Benefit)			3.90%	38.90%
Federal statutory income tax rate, percent			21.00%	35.00%
Effective income tax rate reconciliation, percent	3.30%		3.90%	9.80%
Income tax (expense) benefit	$ (740)	$ (7,959)	$ (3,336)	$ 1,134
Income (loss) before income taxes	22,581	$ 12,249	86,593	$ (11,559)
Unrecognized Tax Benefits	$ 1,313		$ 1,313
Effective Income Tax Rate Reconciliation, Deduction, Percent			50.00%	30.00%