Off-Balance Sheet Financial Instruments and Guarantees (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Loss Contingencies [Line Items]
Financial instrument commitments	$ 203,733	$ 119,347
Commitments to grant loans [Member]
Loss Contingencies [Line Items]
Financial instrument commitments	76,029	49,806
Unfunded commitments under lines of credit [Member]
Loss Contingencies [Line Items]
Financial instrument commitments	122,050	65,854
Standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument commitments	$ 5,654	$ 3,687