Stockholders' equity - Schedule of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period			$ 382,150
Balance at end of period	$ 367,657		367,657
Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(179,857)	$ (169,655)	(178,191)	$ (171,235)
Other comprehensive loss	(1,219)	(8,741)	(2,885)	(7,161)
Balance at end of period	(181,076)	(178,396)	(181,076)	(178,396)
Accumulated Defined Benefit Plans Adjustment | Defined Benefit Pension Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(43,464)	(67,595)	(43,857)	(68,468)
Other comprehensive loss	534	856	927	1,729
Plan settlement	4,142		4,142
Balance at end of period	(38,788)	(66,739)	(38,788)	(66,739)
Accumulated Defined Benefit Plans Adjustment | OPEB
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(953)	(1,121)	(893)	(1,053)
Other comprehensive loss	(58)	(63)	(118)	(131)
Balance at end of period	(1,011)	(1,184)	(1,011)	(1,184)
Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(94)		(50)
Other comprehensive loss	(129)		(173)
Balance at end of period	(223)		(223)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(224,368)	(238,371)	(222,991)	(240,756)
Other comprehensive loss	3,270	(7,948)	1,893	(5,563)
Balance at end of period	$ (221,098)	$ (246,319)	$ (221,098)	$ (246,319)