Parent Company Only Condensed Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities [Abstract]
Net income	$ 23,556	$ 10,851
Adjustments to reconcile net income to net cash used in operating activities:
Amortization of debt issuance costs	55	72
Decrease (increase) in other assets	(5)	1,398
(Decrease) increase in accrued interest payable	(375)	(134)
(Decrease) increase in other liabilities	128	239
Net cash provided by operating activities	25,049	13,192
Cash flows from investing activities [Abstract]
Net cash (used in) provided by investing activities	(374,146)	89,850
Cash flows from financing activities [Abstract]
Proceeds from issuance of subordinated debentures, net of issuance costs	0	24,455
Repayment of note payable	0	(15,000)
Net proceeds from issuance of common stock	27,771	113
Payments related to tax withholding for equity awards	(28)	0
Cash dividends paid to common stockholders	(2,052)	0
Net cash provided by (used in) financing activities	332,500	(16,707)
(Decrease) increase in cash and cash equivalents	(16,597)	86,335
Cash and cash equivalents, beginning of period	166,544	80,209
Cash and cash equivalents, end of period	149,947	166,544
Supplemental non-cash disclosures [Abstract]
Common stock issued in acquisition	0	31,252
Parent Company [Member]
Cash flows from operating activities [Abstract]
Net income	23,556	10,851
Adjustments to reconcile net income to net cash used in operating activities:
Equity in undistributed earnings of the bank	(24,252)	(11,916)
Amortization of debt issuance costs	55	72
Decrease (increase) in other assets	909	(295)
(Decrease) increase in accrued interest payable	(3)	542
(Decrease) increase in other liabilities	(223)	235
Net cash provided by operating activities	42	(511)
Cash flows from investing activities [Abstract]
Investment in Bank	(26,000)	(9,000)
Net cash (used in) provided by investing activities	(26,000)	(9,000)
Cash flows from financing activities [Abstract]
Proceeds from issuance of subordinated debentures, net of issuance costs	0	24,455
Repayment of note payable	0	(15,000)
Net proceeds from issuance of common stock	27,771	113
Payments related to tax withholding for equity awards	(28)	0
Cash dividends paid to common stockholders	(2,052)	0
Net cash provided by (used in) financing activities	25,691	9,568
(Decrease) increase in cash and cash equivalents	(267)	57
Cash and cash equivalents, beginning of period	571	514
Cash and cash equivalents, end of period	304	571
Supplemental non-cash disclosures [Abstract]
Common stock issued in acquisition	0	31,252
Stock options rolled over in acquisition	$ 0	$ 1,269