Commitments and contingencies - Changes in Accrued Environmental Remediation and Related Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Commitments and contingencies
Balance at the beginning of the period	$ 92,940	$ 93,416	$ 94,508
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Current liability, Noncurrent liability	Current liability, Noncurrent liability	Current liability, Noncurrent liability
Additions charged to expense, net	$ 486	$ 788	$ 82
Payments, net	(1,068)	(1,264)	(1,174)
Balance at the end of the period	92,358	92,940	93,416
Amounts recognized in the Condensed Consolidated Balance Sheet at the end of the period:
Current liability	2,627	2,643	2,027
Noncurrent liability	$ 89,731	$ 90,297	$ 91,389