Benefit Plans - Schedule of Net Benefit Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Atlas Bank Retirement Income Plan ("ABRIP") [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 62	$ 61	$ 77
Expected return on assets	$ (110)	$ (113)	$ (112)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Amortization of net actuarial (gain) loss	$ 21	$ 22	$ 4
Net periodic benefit cost	$ (27)	$ (30)	$ (31)
Discount rate	3.00%	2.75%	3.75%
Long term rate of return on plan assets	3.50%	3.50%	3.50%
Benefit Equalization Plan ("BEP") [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 86	$ 85	$ 112
Amortization of net actuarial (gain) loss	71	75	56
Net periodic benefit cost	$ 157	$ 160	$ 168
Discount rate	3.00%	2.75%	3.75%
Postretirement Welfare Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 116	$ 106	$ 78
Interest cost	33	27	26
Amortization of net actuarial (gain) loss	(12)	(14)	(41)
Net periodic benefit cost	$ 137	$ 119	$ 63
Discount rate	3.00%	2.75%	3.75%
Salary increase rate	3.25%	3.25%	3.25%
Directors' Consultation and Retirement Plan ("DCRP") [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 92	$ 89	$ 110
Net periodic benefit cost	$ 92	$ 89	$ 110
Discount rate	3.00%	2.75%	3.75%
Supplemental Executive Retirement Plan (SERP) member
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 431
Interest cost	6
Net periodic benefit cost	$ 437
Discount rate	3.00%
Salary increase rate	4.00%