Pension Plans and Other Postretirement Benefits - Net Periodic Benefit Cost for Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 20,513	$ 19,944	$ 17,294
Interest cost on benefit obligation	61,873	71,421	81,579
Expected return on plan assets	(143,448)	(125,512)	(122,139)
Amortization of prior service cost	553	557	557
Recognized net actuarial (gain) loss	89,017	58,096	21,992
Net periodic pension cost (benefit)	28,508	24,506	(717)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,014	970	859
Interest cost on benefit obligation	1,311	1,741	2,344
Amortization of prior service cost	(4,738)	(4,738)	(4,730)
Recognized net actuarial (gain) loss	(1,295)	(1,236)	(1,247)
Net periodic pension cost (benefit)	$ (3,708)	$ (3,263)	$ (2,774)