Benefit Plans - Schedule of Net Funded Status (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Atlas Bank Retirement Income Plan ("ABRIP") [Member]
Change in benefit obligation:
Projected benefit obligation - beginning	$ 2,149,000	$ 2,285,000
Interest cost	62,000	61,000	$ 77,000
Actuarial gain	(247,000)	(49,000)
Benefit payments	(148,000)	(148,000)
Projected benefit obligation - ending	1,816,000	2,149,000	2,285,000
Change in plan assets:
Fair value of assets - beginning	3,220,000	3,299,000
Actual return on assets	(165,000)	69,000
Benefit payments	(148,000)	(148,000)
Fair value of assets - ending	2,907,000	3,220,000	3,299,000
Reconciliation of funded status:
Projected benefit obligation	(1,816,000)	(2,149,000)	(2,285,000)
Fair value of assets - ending	2,907,000	3,220,000	3,299,000
Funded status included in other assets / liabilities	1,091,000	1,071,000
Accumulated benefit obligation	$ (1,816,000)	$ (2,149,000)
Discount rate	4.50%	3.00%
Benefit Equalization Plan ("BEP") [Member]
Change in benefit obligation:
Projected benefit obligation - beginning	$ 2,999,000	$ 3,206,000
Interest cost	86,000	85,000	112,000
Actuarial gain	(252,000)	(53,000)
Benefit payments	(241,000)	(239,000)
Projected benefit obligation - ending	2,592,000	2,999,000	3,206,000
Change in plan assets:
Benefit payments	(241,000)	(239,000)
Contributions	241,000	239,000	237,000
Reconciliation of funded status:
Projected benefit obligation	(2,592,000)	(2,999,000)	(3,206,000)
Funded status included in other assets / liabilities	(2,592,000)	(2,999,000)
Accumulated benefit obligation	$ (2,592,000)	$ (2,999,000)
Discount rate	4.50%	3.00%
Postretirement Welfare Plan [Member]
Change in benefit obligation:
Projected benefit obligation - beginning	$ 1,108,000	$ 991,000
Service cost	116,000	106,000	78,000
Interest cost	33,000	27,000	26,000
Actuarial gain	(160,000)	(4,000)
Benefit payments	(12,000)	(12,000)
Projected benefit obligation - ending	1,085,000	1,108,000	991,000
Change in plan assets:
Benefit payments	(12,000)	(12,000)
Contributions	12,000	12,000	11,000
Reconciliation of funded status:
Projected benefit obligation	(1,085,000)	(1,108,000)	(991,000)
Funded status included in other assets / liabilities	$ (1,085,000)	$ (1,108,000)
Discount rate	4.50%	3.00%
Salary increase rate	3.25%	3.25%
Directors' Consultation and Retirement Plan ("DCRP") [Member]
Change in benefit obligation:
Projected benefit obligation - beginning	$ 3,116,000	$ 3,269,000
Interest cost	92,000	89,000	110,000
Actuarial gain	(513,000)	(173,000)
Benefit payments	(49,000)	(69,000)
Projected benefit obligation - ending	2,646,000	3,116,000	3,269,000
Change in plan assets:
Benefit payments	(49,000)	(69,000)
Contributions	49,000	69,000	60,000
Reconciliation of funded status:
Projected benefit obligation	(2,646,000)	(3,116,000)	$ (3,269,000)
Funded status included in other assets / liabilities	(2,646,000)	(3,116,000)
Accumulated benefit obligation	$ (2,646,000)	$ (3,116,000)
Discount rate	4.50%	3.00%
Supplemental Executive Retirement Plan SERP [Member]
Change in benefit obligation:
Projected benefit obligation - beginning	$ 0
Service cost	431,000
Interest cost	6,000
Projected benefit obligation - ending	437,000	$ 0
Reconciliation of funded status:
Projected benefit obligation	(437,000)	$ 0
Funded status included in other assets / liabilities	$ (437,000)
Discount rate	3.00%
Salary increase rate	4.00%