Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Current expense									$ 598	$ 379
Deferred expense									2,308	1,792
Total expense	$ 554	$ 863	$ 855	$ 634	$ 639	$ 325	$ 517	$ 690	$ 2,906	$ 2,171