Income Taxes Income Taxes - Unrecognized Tax Benefits Table (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2020	Sep. 30, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 1,100,000	$ 1,600,000	$ 1,600,000
(Decrease) increase for tax positions taken in prior periods	500,000	(1,600,000)	0
Balance at end of period	1,600,000	0	1,600,000
Unrecognized Tax Benefits, Interest on Income Taxes Expense	0	0	0
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 0	$ 0	$ 0