Retirement plans (Tables)

3 Months Ended

Mar. 31, 2022

Retirement Benefits [Abstract]

Schedule of Benefit Costs (Income)

Pension costs (income), which primarily include costs for the qualified TRP and the non-qualified SERP, are presented in the following table (in thousands):

	Quarter ended Mar. 31,
	2022		2021
Interest cost on benefit obligation	$	4,300	$	3,950
Expected return on plan assets	(4,900)		(8,650)
Amortization of prior service cost	(125)		25
Amortization of actuarial loss	1,100		1,200
Expense (income) from company-sponsored retirement plans	$	375	$	(3,475)