Employee benefit plans (Tables)

9 Months Ended

Sep. 30, 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 September 30,	2020		2019		2020		2019
	(In thousands)
Components of net periodic benefit cost (credit):
Service cost	$	—	$	—	$	383	$	286
Interest cost	3,023		3,806		609		746
Expected return on assets	(4,987)		(4,559)		(1,115)		(1,201)
Amortization of prior service credit	—		—		(349)		(289)
Amortization of net actuarial loss	1,793		1,387		71		27
Net periodic benefit cost (credit), including amount capitalized	(171)		634		(401)		(431)
Less amount capitalized	—		—		39		26
Net periodic benefit cost (credit)	$	(171)	$	634	$	(440)	$	(457)

	Pension Benefits				Other Postretirement Benefits
Nine Months Ended September 30,	2020		2019		2020		2019
	(In thousands)
Components of net periodic benefit cost (credit):
Service cost	$	—	$	—	$	1,149	$	857
Interest cost	9,070		11,419		1,827		2,239
Expected return on assets	(14,962)		(13,677)		(3,764)		(3,603)
Amortization of prior service credit	—		—		(1,048)		(866)
Amortization of net actuarial loss	5,379		4,160		215		82
Net periodic benefit cost (credit), including amount capitalized	(513)		1,902		(1,621)		(1,291)
Less amount capitalized	—		—		106		84
Net periodic benefit cost (credit)	$	(513)	$	1,902	$	(1,727)	$	(1,375)