Retirement plans (Tables)

6 Months Ended

Jun. 30, 2021

Retirement Benefits [Abstract]

Schedule of Benefit Costs

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 June 30,				Six months ended June 30,
	2021		2020		2021		2020
Service cost-benefits earned during the period	$	1	$	2	$	1	$	4
Interest cost on benefit obligation	3,988		4,879		7,938		9,737
Expected return on plan assets	(8,690)		(7,779)		(17,340)		(15,529)
Amortization of prior service cost	20		87		45		45
Amortization of actuarial loss	1,246		1,481		2,446		3,081
Income from company-sponsored retirement plans	$	(3,435)	$	(1,330)	$	(6,910)	$	(2,662)