Postretirement benefits (Tables)

6 Months Ended

Jun. 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 June 30,				Six Months Ended June 30,
(in thousands)	2021		2020		2021		2020
Interest cost	$	242	$	478	$	484	$	956
Expected return on plan assets	(1,875)		(1,905)		(3,748)		(3,809)
Amortization of prior service credit	(355)		(355)		(711)		(711)
Amortization of net actuarial losses	407		575		814		1,150
Net periodic benefit income	$	(1,581)	$	(1,207)	$	(3,161)	$	(2,414)