ACCUMULATED OTHER COMPREHENSIVE INCOME/ (LOSS) - Reclassification Adjustments Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Investment securities gains/ (losses)	$ (345)	$ 212	$ 467
Interest and dividends on investment securities	495,667	450,284	423,560
Recognized net actuarial loss	783	909	874
Settlement charge	0	(560)	0
Income before taxes	222,358	311,659	124,424
Tax expense (benefit)	(56,059)	(76,552)	(27,471)
Net income	166,299	235,107	96,953
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains/ (Losses) on Investments Available-for-Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Investment securities gains/ (losses)	(345)	212	467
Income before taxes	(345)	212	467
Tax expense (benefit)	88	(54)	(120)
Net income	(257)	158	347
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Losses on Debt Securities Transferred from Available-for-Sale to Held-to-Maturity
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and dividends on investment securities	(2,245)	0	0
Income before taxes	(2,245)	0	0
Tax expense (benefit)	598	0	0
Net income	(1,647)	0	0
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Recognized net actuarial loss	(783)	(909)	(874)
Settlement charge	0	(560)	0
Reclassification out of Accumulated Other Comprehensive Income | Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before taxes	(783)	(1,469)	(874)
Tax expense (benefit)	199	376	223
Net income	$ (584)	$ (1,093)	$ (651)