Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Federal statutory rate									$ 2,822	$ 2,104
State taxes, net									376	554
Other permanent items									96	160
Deferred tax estimate adjustment									0	88
Total expense	$ 339	$ 1,166	$ 1,049	$ 741	$ 554	$ 863	$ 855	$ 634	$ 3,294	$ 2,906