Comprehensive Income/(Loss) - Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains reclassified into earnings	$ (145)	$ 650
Provision for income taxes	9,942	9,859
Employee benefits (Non-interest expense)	12,060	9,158
Net effect on accumulated other comprehensive income/(loss) for the period	189	55
Accumulated Unrealized Gains (Losses) on Debt Securities Available for Sale [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net effect on accumulated other comprehensive income/(loss) for the period	114	1
Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net effect on accumulated other comprehensive income/(loss) for the period	75	54
Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Unrealized Gains (Losses) on Debt Securities Available for Sale [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains reclassified into earnings	151	2
Provision for income taxes	(37)	(1)
Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for income taxes	(23)	(18)
Employee benefits (Non-interest expense)	$ 98	$ 72