Employee benefit plans (Tables)

3 Months Ended

Mar. 31, 2020

Retirement Benefits [Abstract]

Schedule of net benefit costs

Components of net periodic benefit cost (credit) for the Company's pension and other postretirement benefit plans were as follows:

	Pension Benefits						Other Postretirement Benefits
Three Months Ended March 31,	2020			2019			2020			2019
	(In thousands)
Components of net periodic benefit cost (credit):
Service cost	$	—		$	—		$	352		$	344
Interest cost	2,973			3,773			591			780
Expected return on assets	(4,761		)	(5,120		)	(1,248		)	(1,220		)
Amortization of prior service credit	—			—			(297		)	(349		)
Amortization of net actuarial loss	1,863			1,355			2			97
Net periodic benefit cost (credit), including amount capitalized	75			8			(600		)	(348		)
Less amount capitalized	—			—			32			31
Net periodic benefit cost (credit)	$	75		$	8		$	(632	)	$	(379	)