Other Comprehensive Income (Loss) - Components of Other Comprehensive Income Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	$ (84,791)	$ (7,339)	$ 9,804
Other comprehensive income (loss), Tax Effect	(17,926)	(1,540)	2,059
Other comprehensive income (loss), Net of Tax	(66,865)	(5,799)	7,745
Net unrealized Gains (Losses) on Investment Securities [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss) before reclassifications	(85,517)	(8,570)	10,935
Amounts reclassified from accumulated other comprehensive income (loss), Before Tax	(10)	(1)	(94)
Other comprehensive income (loss), before tax	(85,527)	(10,841)	8,571
Other comprehensive income (loss) before reclassifications	(18,079)	(1,799)	2,297
Amounts reclassified from accumulated other comprehensive income (loss), Tax Effect	(2)	0	(20)
Other comprehensive income (loss), Tax Effect	(18,081)	(2,277)	1,799
Other comprehensive income (loss) before reclassifications, Net of Tax	(67,438)	(6,771)	8,638
Amounts reclassified from accumulated other comprehensive income (loss), Net of Tax	(8)	(1)	(74)
Other comprehensive income (loss), Net of Tax	(67,446)	(8,564)	6,772
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss) before reclassifications	736	992	(1,326)
Amounts reclassified from accumulated other comprehensive income (loss), Before Tax	0	240	289
Other comprehensive income (loss), before tax	736	1,232	(1,037)
Other comprehensive income (loss) before reclassifications	155	209	(279)
Amounts reclassified from accumulated other comprehensive income (loss), Tax Effect	0	50	61
Other comprehensive income (loss), Tax Effect	155	259	(218)
Other comprehensive income (loss) before reclassifications, Net of Tax	581	783	(1,047)
Amounts reclassified from accumulated other comprehensive income (loss), Net of Tax	0	190	228
Other comprehensive income (loss), Net of Tax	$ 581	$ 973	$ (819)