Pension Plan and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2022

Retirement Benefits [Abstract]

Schedule of components of net periodic benefit costs for the pension plans and other postretirement benefits

The following tables list components of net periodic benefit costs for the pension plans and other postretirement benefits. The data listed under “pension plan” includes the qualified pension plan and the non-qualified supplemental executive retirement plan. The data listed under “other benefits” is for all other postretirement benefits.

	Three Months Ended September 30
	Pension Plan				Other Benefits
	2022		2021		2022		2021
Service cost	$	9,235	$	8,308	$	1,683	$	1,332
Interest cost	6,329		5,608		1,008		802
Expected return on plan assets	(11,307)		(9,873)		(2,482)		(2,194)
Amortization of prior service cost	242		248		39		48
Recognized net actuarial loss	999		2,881		(228)		(145)
Net periodic benefit cost	$	5,498	$	7,172	$	20	$	(157)

	Nine Months Ended September 30
	Pension Plan				Other Benefits
	2022		2021		2022		2021
Service cost	$	27,704	$	26,329	$	5,048	$	4,554
Interest cost	18,986		16,245		3,024		2,413
Expected return on plan assets	(33,920)		(29,605)		(7,445)		(6,577)
Amortization of prior service cost	727		755		117		145
Recognized net actuarial loss	2,997		6,729		(685)		(365)
Net periodic benefit cost	$	16,494	$	20,453	$	59	$	170