Pension plans and other postretirement benefits (Tables)

9 Months Ended

Sep. 30, 2020

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 September 30
	2020			2019			2020			2019
	(In thousands)
Service cost	$	4,986			4,324			242		215
Interest cost on projected benefit obligation		17,855			20,394			436			586
Expected return on plan assets		(31,378	)		(30,534	)		—			—
Amortization of prior service cost (credit)		125			139			(1,175	)		(1,182	)
Amortization of net actuarial loss (gain)		13,950			5,498			(300	)		(312	)
Net periodic cost (benefit)	$	5,538			(179	)		(797	)		(693	)
	Pension Benefits						Other Postretirement Benefits
	Nine Months Ended September 30
	2020			2019			2020			2019
	(In thousands)
Service cost	$	14,958			12,970			727			644
Interest cost on projected benefit obligation		53,565			61,184			1,306			1,758
Expected return on plan assets		(94,134	)		(91,604	)		—			—
Amortization of prior service cost (credit)		404			418			(3,544	)		(3,547	)
Amortization of net actuarial loss (gain)		42,998			16,494			(918	)		(935	)
Net periodic cost (benefit)	$	17,791			(538	)		(2,429	)		(2,080	)