Accumulated Other Comprehensive Income (AOCI) - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gain on securities available-for-sale	$ 4,875
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified amount before tax	96	$ 6
Reclassification out of Accumulated Other Comprehensive Income | Net realized gains on sale of AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gain on securities available-for-sale	90
Reclassification out of Accumulated Other Comprehensive Income | Compensation and benefits (included in computation of net periodic pension costs)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of defined benefit pension items:	6	6
Reclassification out of Accumulated Other Comprehensive Income | Provision for income tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax benefit	20	1
Reclassification out of Accumulated Other Comprehensive Income | Net Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassification out of AOCI	$ 76	$ 5