Investment Securities: Narrative-Realized Gains (Losses) (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2023 USD ($) security	Mar. 31, 2022 USD ($) security	Sep. 30, 2022 USD ($)
Investments [Abstract]
Loss on sale of securities	$ 9	$ 1
Held-to-maturity securities, realized loss, number of securities | security	14	14
Security owned and pledged as collateral	$ 215,330		$ 133,820