Pension plans and other postretirement benefits (Tables)

3 Months Ended

Mar. 31, 2022

Compensation And Retirement Disclosure [Abstract]

Net Periodic Defined Benefit Cost for Defined Benefit Plans

Net periodic defined benefit cost for defined benefit plans consisted of the following:

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended March 31
	2022			2021			2022			2021
	(In thousands)
Service cost	$	4,271		$	5,023		$	232		$	248
Interest cost on projected benefit obligation		16,267			15,434			355			327
Expected return on plan assets		(37,150	)		(35,950	)		—			—
Amortization of prior service cost (credit)		125			125			(1,075	)		(1,175	)
Amortization of net actuarial loss (gain)		4,625			22,150			(325	)		(300	)
Net periodic cost (benefit)	$	(11,862	)	$	6,782		$	(813	)	$	(900	)