Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and contingencies.

Schedule of Changes in Accrued Environmental Remediation and Related Costs

	Years ended December 31,
	2021		2022		2023
	(In thousands)
Balance at the beginning of the period	$	93,416	$	92,940	$	92,358
Additions charged to expense, net		788		486		558
Payments, net		(1,264)		(1,068)		(1,810)
Balance at the end of the period	$	92,940	$	92,358	$	91,106
Amounts recognized in the balance sheet:
Current liability	$	2,643	$	2,627	$	1,655
Noncurrent liability		90,297		89,731		89,451
Balance at the end of the period	$	92,940	$	92,358	$	91,106