Commitments and Contingencies: Supply Commitment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Undisbursed portion of construction loans in process (see Note 5)	$ 95,224	$ 100,558
Undisbursed lines of credit	115,865	103,030
Commitments to extend credit	$ 47,422	$ 38,581