Pensions and other postretirement benefit plans (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Summary of benefit costs

Retirement plan costs include the following components:

	Three months ended
	September 30, 2020					September 29, 2019
In thousands	Pension			OPEB		Pension			OPEB
Operating expenses:
Service cost - Benefits earned during the period	$	693		$	27	$	159		$	—
Non-operating expenses (Other income):
Interest cost on benefit obligation	20,670			580		737			22
Expected return on plan assets	(39,573		)	—		(937		)	—
Amortization of actuarial loss (gain)	(26		)	15		(39		)	9
Total non-operating expenses (benefit)	$	(18,929	)	$	595	$	(239	)	$	31
Total expense (benefit) for retirement plans	$	(18,236	)	$	622	$	(80	)	$	31

	Nine months ended
	September 30, 2020					September 29, 2019
In thousands	Pension			OPEB		Pension			OPEB
Operating expenses:
Service cost - Benefits earned during the period	$	2,078		$	79	$	476		$	—
Non-operating expenses (Other income):
Interest cost on benefit obligation	61,803			1,740		2,210			67
Expected return on plan assets	(117,940		)	—		(2,812		)	—
Amortization of actuarial loss (gain)	(80		)	44		(117		)	27
Total non-operating expenses (benefit)	$	(56,217	)	$	1,784	$	(719	)	$	94
Total expense (benefit) for retirement plans	$	(54,139	)	$	1,863	$	(243	)	$	94