Changes in Accumulated Other Comprehensive Income (Loss) (AOCI) by Component - Amounts Reclassified from Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gains (losses) on available-for-sale securities	$ 0	$ 12	$ 0	$ (171)
Tax expense	243	202	465	1,428
Net Income	708	690	1,359	4,063
Amounts Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassified amount before tax	(1)	10	2	(176)
Tax expense	0	4	1	(49)
Net Income	(1)	6	1	(127)
Accumulated Net Realized Investment Gains (Losses) [Member] | Amounts Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gains (losses) on available-for-sale securities	0	12	0	(171)
Amortization of Defined Benefit Pension Items [Member] | Amounts Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Actuarial losses	$ (1)	$ (2)	$ 2	$ (5)