Loans and Allowance for Credit Losses - Loan portfolio aging analysis (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	$ 2,237,091	$ 2,171,463
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,238	1,686
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,369	1,977
Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,211	2,730
Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	3,818	6,393
Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	2,233,273	2,165,070
Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	721,216	627,357
Residential Real Estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	312	772
Residential Real Estate | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	364	378
Residential Real Estate | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	613	654
Residential Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,289	1,804
Residential Real Estate | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	719,927	625,553
Construction Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	134,284	107,472
Construction Real Estate | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	30
Construction Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	30
Construction Real Estate | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	134,254	107,472
Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	889,793	887,419
Commercial Real Estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	363	641
Commercial Real Estate | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable		327
Commercial Real Estate | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	374	1,073
Commercial Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	737	2,041
Commercial Real Estate | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	889,056	885,378
Consumer loans
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	77,674	80,767
Consumer loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	195	180
Consumer loans | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	66	53
Consumer loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	84	193
Consumer loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	345	426
Consumer loans | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	77,329	80,341
Commercial loans
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	414,124	468,448
Commercial loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	368	93
Commercial loans | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	939	1,219
Commercial loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	110	810
Commercial loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,417	2,122
Commercial loans | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	$ 412,707	$ 466,326