Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Estimated Annual Effective Tax Rate Used to Calculate Income Tax Expense (Benefit)	13.80%	4.90%
Federal statutory income tax rate, percent	21.00%
Effective income tax rate reconciliation, percent	14.30%	4.60%
Income tax expense	$ (1,084)	$ (2,603)
Income before income taxes	7,561	$ 56,109
Unrecognized Tax Benefits	$ 1,322