Pension Plans and Other Postretirement Benefits - Net Periodic Benefit Cost for Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 17,660	$ 20,513	$ 19,944
Interest cost on benefit obligation	82,467	61,873	71,421
Expected return on plan assets	(187,609)	(143,448)	(125,512)
Amortization of prior service cost	516	553	557
Recognized net actuarial (gain) loss	19,895	89,017	58,096
Net periodic pension cost (benefit)	$ (67,071)	$ 28,508	$ 24,506
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,604	$ 1,014	$ 970
Interest cost on benefit obligation	2,188	1,311	1,741
Amortization of prior service cost	(2,772)	(4,738)	(4,738)
Recognized net actuarial (gain) loss	(1,481)	(1,295)	(1,236)
Net periodic pension cost (benefit)	$ (539)	$ (3,708)	$ (3,263)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Noninterest Expense	Other Noninterest Expense	Other Noninterest Expense