Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Estimated Annual Effective Tax Rate Used to Calculate Income Tax Expense (Benefit)			14.60%	4.50%
Federal statutory income tax rate, percent			21.00%	21.00%
Effective income tax rate reconciliation, percent	34.70%	0.09%	24.70%	4.06%
Income tax (expense) benefit	$ (2,701)	$ 7	$ (3,785)	$ (2,596)
Income before income taxes	7,783	7,903	15,344	64,012
Unrecognized Tax Benefits	$ 1,752	$ 1,309	$ 1,752	$ 1,309