Loan Servicing Rights - Analysis of the changes in MSRs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Freddie Mac
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance, beginning of year	$ 2,980	$ 2,206	$ 2,022
Additions	1,388	1,733	747
Amortization	(1,022)	(748)	(563)
Valuation recovery (allowance)	92	(211)	0
Balance, end of year	3,438	2,980	2,206
SBA
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance, beginning of year	115	202	6
Additions due to South Sound Acquisition	0	0	285
Other additions	0	13	2
Amortization	(89)	(90)	(83)
Valuation recovery (allowance)	18	(10)	(4)
Balance, end of year	44	115	202
SBA | South Sound Merger
Servicing Asset at Fair Value, Amount [Roll Forward]
Valuation recovery (allowance)	$ 0	$ 0	$ (4)