Benefit Plans - Schedule of Net Periodic Benefit Expense (Detail) - Benefit Equalization Plan, Postretirement Welfare Plan, Directors Consultation and Retirement Plan and Atlas Bank Retirement Income Plan and Supplemental Executive Retirement Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 279	$ 262	$ 326
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Amortization of unrecognized loss	$ 80	$ 83	$ 19
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Expected return on assets	$ (110)	$ (113)	$ (112)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Salaries and Employee Benefits [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 547	$ 106	$ 78
Other Expense [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	$ 796	$ 338	$ 311