Condensed Financial Information - Parent Company Only: Condensed Balance Sheets, Parent Company (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Cash and cash equivalents:
Cash and due from financial institutions	$ 25,390	$ 24,808
Interest-bearing deposits in banks	103,331	291,947
Total cash and cash equivalents	128,721	316,755
Mortgage-backed securities and other investments held to maturity-fair value	253,766	249,783
Other assets	3,573	3,364
Total assets	1,839,905	1,860,508
Liabilities and shareholders’ equity
Shareholders’ equity	233,073	218,569	$ 206,899	$ 187,630
Total liabilities and shareholders’ equity	1,839,905	1,860,508
Parent Company
Cash and cash equivalents:
Cash and due from financial institutions	517	162
Interest-bearing deposits in banks	0	1,548
Total cash and cash equivalents	517	1,710	$ 2,932	$ 2,633
Mortgage-backed securities and other investments held to maturity-fair value	449	469
Investment securities held to maturity, at amortized cost (estimated fair value $449 and $469)	500	500
Investment in Bank	232,145	216,348
Other assets	51	56
Total assets	233,213	218,614
Liabilities and shareholders’ equity
Accrued expenses	140	45
Shareholders’ equity	233,073	218,569
Total liabilities and shareholders’ equity	$ 233,213	$ 218,614