Pension plans and other postretirement benefits (Tables)

9 Months Ended

Sep. 30, 2019

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
	2019			2018			2019			2018
	(In thousands)
Service cost	$	4,324			5,086			215		234
Interest cost on projected benefit obligation		20,394			18,676			586			573
Expected return on plan assets		(30,534	)		(30,781	)		—			—
Amortization of prior service cost (credit)		139			139			(1,182	)		(1,182	)
Amortization of net actuarial loss (gain)		5,498			10,948			(312	)		(206	)
Net periodic cost (benefit)	$	(179	)		4,068			(693	)		(581	)

	Pension Benefits						Other Postretirement Benefits
	Nine Months Ended September 30
	2019			2018			2019			2018
	(In thousands)
Service cost	$	12,970			15,258			644			703
Interest cost on projected benefit obligation		61,184			56,029			1,758			1,719
Expected return on plan assets		(91,604	)		(92,344	)		—			—
Amortization of prior service cost (credit)		418			417			(3,547	)		(3,546	)
Amortization of net actuarial loss (gain)		16,494			32,844			(935	)		(619	)
Net periodic cost (benefit)	$	(538	)		12,204			(2,080	)		(1,743	)