Accumulated Other Comprehensive (Loss) Income, Net of Tax (Schedule of Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ (62,648)	$ (54,812)	$ (128,477)	$ (21,212)
Net of tax	(2,392)	(1,062)	(18,362)	(2,130)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	(600)	(762)	(1,192)	(1,531)
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	223	283	443	569
Net of tax	(600)	(762)	(1,192)	(1,531)
Hedge terminations	(99)	(76)	(175)	(153)
Premium amortization	(724)	(969)	(1,460)	(1,947)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss)
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Actuarial net loss amortization	(2,410)	(411)	(2,952)	(822)
Defined benefit pension and postretirement benefit plans
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	(1,757)	(300)	(2,152)	(599)
Income tax expense	653	111	800	223
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	13		5,513	0
Net of tax	(35)	0	(15,018)	0
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 holding (losses)	$ (48)	0	$ (20,531)	$ 0
Income tax expense		$ 0