Accumulated Other Comprehensive Income (Loss) - Reclassification Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Significant amounts reclassified out of accumulated other comprehensive income [Abstract]
Realized gains on securities available-for-sale	$ 105	$ 240
Tax effect	6,939	3,201
Unrealized Gains and Losses on Available-for-Sale Debt Securities
Significant amounts reclassified out of accumulated other comprehensive income [Abstract]
Net of tax	81	191
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Unrealized Gains and Losses on Available-for-Sale Debt Securities
Significant amounts reclassified out of accumulated other comprehensive income [Abstract]
Realized gains on securities available-for-sale	105	240
Tax effect	(24)	(49)
Net of tax	$ 81	$ 191