Federal Income Taxes: Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Federal									$ 6,139	$ 6,570	$ 5,962
Deferred									(177)	275	76
Provision for income taxes	$ 1,785	$ 1,472	$ 1,316	$ 1,389	$ 1,525	$ 1,786	$ 1,651	$ 1,883	$ 5,962	$ 6,845	$ 6,038