Fair Value Measurements - Schedule of financial instruments (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023
Financial assets
Cash and cash equivalents	$ 88,193	$ 53,979
Interest-bearing time deposits	987	1,242
Stock in FHLB	10,900	11,540
Stock in Federal Reserve Bank of St. Louis	9,060	9,061
Loans receivable, net	3,650,557	3,571,078
Accrued interest receivable	23,642	18,871
Financial liabilities
Deposits	3,841,126	3,725,540
Advances from FHLB	114,026	133,514
Accrued interest payable	7,101	4,723
Subordinated debt	23,118	23,105
Unrecognized financial instruments (net of contract amount)
Commitments to originate loans	0
Letters of credit	0
Lines of credit	0
Fair Value, Inputs, Level 1
Financial assets
Cash and cash equivalents	88,193	53,979
Financial liabilities
Deposits	2,562,664	2,661,479
Fair Value, Inputs, Level 2
Financial assets
Interest-bearing time deposits	987	1,242
Stock in FHLB	10,900	11,540
Stock in Federal Reserve Bank of St. Louis	9,060	9,061
Accrued interest receivable	23,642	18,871
Financial liabilities
Advances from FHLB	111,439	131,821
Accrued interest payable	7,101	4,723
Fair Value, Inputs, Level 3
Financial assets
Loans receivable, net	3,408,166	3,393,791
Financial liabilities
Deposits	1,263,342	1,053,650
Subordinated debt	$ 20,845	$ 20,318