Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income [Line Items]
Beginning balance	$ (20,559)	$ (21,648)
Other comprehensive income (loss) before reclassification	4,703	(5,121)
Amounts reclassified from accumulated other comprehensive income (loss)	51
Net current period other comprehensive income	(2)	2
Ending balance	(15,807)	(26,767)
Unrealized Gains and Losses on Available-for- Sale Securities [Member]
Accumulated Other Comprehensive Income [Line Items]
Beginning balance	(20,768)	(21,715)
Other comprehensive income (loss) before reclassification	4,703	(5,121)
Amounts reclassified from accumulated other comprehensive income (loss)	51
Net current period other comprehensive income	0	0
Ending balance	(16,014)	(26,836)
Defined Benefit Pension Items [Member]
Accumulated Other Comprehensive Income [Line Items]
Beginning balance	209	67
Other comprehensive income (loss) before reclassification	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net current period other comprehensive income	(2)	2
Ending balance	$ 207	$ 69