Fair Value Measurements: Level 3 Fair Value Measurements, Nonrecurring (Details) - Nonrecurring - Fair Value, Inputs, Level 3 - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, estimated fair value, nonrecurring	$ 123	$ 566
Total impaired loans
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, estimated fair value, nonrecurring	123	409
OREO and other repossessed assets
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, estimated fair value, nonrecurring		157
Market approach | Total impaired loans
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, estimated fair value, nonrecurring	$ 123	409
Market approach | OREO and other repossessed assets
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, estimated fair value, nonrecurring		$ 157