Other Comprehensive Income (Loss) - Components of Other Comprehensive Income Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), Before Tax	$ (7,371)	$ 13,302	$ (84,791)
Other comprehensive income (loss), Tax Effect	(1,544)	2,787	(17,926)
Other comprehensive income (loss), Net of Tax	(5,827)	10,515	(66,865)
Net unrealized Losses on Investment Securities [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive gain before reclassifications	(7,338)	12,330	(85,517)
Amounts reclassified from accumulated other comprehensive loss	(33)	0	(10)
Other comprehensive income (loss), Before Tax	(7,371)	12,330	(85,527)
Other comprehensive income (loss), before reclassifications	(1,537)	2,583	(18,079)
Amounts reclassified from accumulated other comprehensive income (loss), Tax Effect	(7)	0	(2)
Other comprehensive income (loss), Tax Effect	(1,544)	2,583	(18,081)
Other comprehensive income (loss) before reclassifications, Net of Tax	(5,801)	9,747	(67,438)
Amounts reclassified from accumulated other comprehensive income (loss), Net of Tax	(26)	0	(8)
Other comprehensive income (loss), Net of Tax	(5,827)	9,747	(67,446)
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive gain before reclassifications	0	972	736
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive income (loss), Before Tax	0	972	736
Other comprehensive income (loss), before reclassifications	0	204	155
Amounts reclassified from accumulated other comprehensive income (loss), Tax Effect	0	0	0
Other comprehensive income (loss), Tax Effect	0	204	155
Other comprehensive income (loss) before reclassifications, Net of Tax	0	768	581
Amounts reclassified from accumulated other comprehensive income (loss), Net of Tax	0	0	0
Other comprehensive income (loss), Net of Tax	$ 0	$ 768	$ 581