Postretirement benefits (Tables)

9 Months Ended

Sep. 30, 2021

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Components of net periodic benefit income

Postretirement benefit income is included in other income on the consolidated statements of comprehensive income (loss) and consisted of the following components:

	Quarter Ended September 30,				Nine Months Ended September 30,
(in thousands)	2021		2020		2021		2020
Interest cost	$	242	$	478	$	726	$	1,434
Expected return on plan assets	(1,875)		(1,905)		(5,623)		(5,714)
Amortization of prior service credit	(355)		(355)		(1,066)		(1,066)
Amortization of net actuarial losses	407		575		1,221		1,725
Net periodic benefit income	$	(1,581)	$	(1,207)	$	(4,742)	$	(3,621)