Pension Plans and Other Postretirement Benefits - Changes in Level 3 Pension Plan Assets Measured at Fair Value on Recurring Basis (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	$ 2,593,533
Fair value of plan assets at end of year	2,938,404
Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	349,039
Fair value of plan assets at end of year	408,411
Other Real Estate Partnerships [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	11,356
Purchase(Sales)	6,062
Total Realized/Unrealized Gains (Losses)	2,884
Fair value of plan assets at end of year	20,302
Other Private Equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	151,550
Purchase(Sales)	66,393
Total Realized/Unrealized Gains (Losses)	(6,845)
Fair value of plan assets at end of year	211,098
Other Hedge Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	176,092
Purchase(Sales)	(2,714)
Total Realized/Unrealized Gains (Losses)	(5,968)
Fair value of plan assets at end of year	167,410
Guaranteed Deposit Fund [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	10,041
Fair value of plan assets at end of year	9,601
Guaranteed Deposit Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	10,041
Purchase(Sales)	819
Total Realized/Unrealized Gains (Losses)	(1,259)
Fair value of plan assets at end of year	9,601
Other Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	537,141
Fair value of plan assets at end of year	632,502
Other Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	349,039
Purchase(Sales)	70,560
Total Realized/Unrealized Gains (Losses)	(11,188)
Fair value of plan assets at end of year	$ 408,411