Employee benefit plans (Tables)

9 Months Ended

Sep. 30, 2023

Retirement Benefits [Abstract]

Schedule of net benefit costs

Components of net periodic benefit credit for the Company's pension benefit plans were as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2023		2022		2023		2022
	(In thousands)
Components of net periodic benefit credit:
Interest cost	$	3,380	$	2,349	$	10,140	$	7,047
Expected return on assets	(4,299)		(4,370)		(12,897)		(13,112)
Amortization of net actuarial loss	773		1,456		2,319		4,370
Net periodic benefit credit	$	(146)	$	(565)	$	(438)	$	(1,695)

Components of net periodic benefit credit for the Company's other postretirement benefit plans were as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2023		2022		2023		2022
	(In thousands)
Components of net periodic benefit credit:
Service cost	$	131	$	223	$	405	$	669
Interest cost	489		346		1,467		1,038
Expected return on assets	(1,334)		(1,319)		(4,026)		(3,957)
Amortization of prior service credit	(330)		(330)		(989)		(989)
Amortization of net actuarial gain	(96)		(142)		(408)		(425)
Net periodic benefit credit, including amount capitalized	(1,140)		(1,222)		(3,551)		(3,664)
Less amount capitalized	23		47		76		131
Net periodic benefit credit	$	(1,163)	$	(1,269)	$	(3,627)	$	(3,795)