Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2022

Commitments and contingencies

Changes in Accrued Environmental Remediation and Related Costs

	Years ended December 31,
	2020		2021		2022
	(In thousands)
Balance at the beginning of the period	$	94,508	$	93,416	$	92,940
Additions charged to expense, net		82		788		486
Payments, net		(1,174)		(1,264)		(1,068)
Balance at the end of the period	$	93,416	$	92,940	$	92,358
Amounts recognized in the balance sheet:
Current liability	$	2,027	$	2,643	$	2,627
Noncurrent liability		91,389		90,297		89,731
Balance at the end of the period	$	93,416	$	92,940	$	92,358