Loans and Allowance for Credit Losses - Loan portfolio aging analysis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	$ 2,283,300	$ 2,237,091
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	2,549	1,238
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	885	1,369
Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,372	1,211
Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	4,806	3,818
Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	2,278,494	2,233,273
Residential Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	762,204	721,216
Residential Real Estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,475	312
Residential Real Estate | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	84	364
Residential Real Estate | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	499	613
Residential Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	2,058	1,289
Residential Real Estate | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	760,146	719,927
Construction Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	127,946	134,284
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	127,946	134,254
Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	901,281	889,793
Commercial Real Estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	598	363
Commercial Real Estate | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	671
Commercial Real Estate | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable		374
Commercial Real Estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,269	737
Commercial Real Estate | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	900,012	889,056
Consumer loans
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	80,467	77,674
Consumer loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	193	195
Consumer loans | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	87	66
Consumer loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	56	84
Consumer loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	336	345
Consumer loans | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	80,131	77,329
Commercial loans
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	411,402	414,124
Commercial loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	283	368
Commercial loans | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	43	939
Commercial loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	817	110
Commercial loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	1,143	1,417
Commercial loans | Current
Financing Receivable, Past Due [Line Items]
Total Loans Receivable	$ 410,259	$ 412,707