Accumulated Other Comprehensive (Loss) Income, Net of Tax (Schedule of Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ (69,346)	$ (65,829)
Net of tax	(9,902)	(15,970)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	(302)	(592)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges | Reclassification out of accumualted comprehensive income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	4	220
Net of tax	(302)	(592)
Hedge terminations	(34)	(76)
Premium amortization	(272)	(736)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss)
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Actuarial net loss amortization	(657)	(542)
Defined benefit pension and postretirement benefit plans
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	(479)	(395)
Income tax expense	178	147
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	3,275
Net of tax	(9,121)	(14,983)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent | Reclassification out of accumualted comprehensive income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net unrealized holding (losses)	$ (12,396)	(20,483)
Income tax expense		$ 5,500