Pensions - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Settlements	$ 184	$ 15,997	$ 775
UNITED STATES
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	103	118	308
Interest cost	680	864	1,198
Settlements		(3,452)
Other	0	0	5
Net periodic benefit cost (income)	(1,147)	(1,459)	(161)
Foreign Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	404	397	495
Interest cost	726	752	789
Settlements		453
Other	0	48	0
Net periodic benefit cost (income)	1,578	1,517	1,592
Pension Plan [Member] | UNITED STATES
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	853	809	852
Interest cost	8,132	10,955	10,824
Expected return on plan assets	(13,683)	(16,353)	(17,414)
Amortization of prior service cost and actuarial loss	1,940	2,914	2,403
Settlements	0	15,247	0
Other	0	0	0
Net periodic benefit cost (income)	(2,758)	13,572	(3,335)
Pension Plan [Member] | Foreign Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	3,992	3,893	4,383
Interest cost	3,200	4,037	4,207
Expected return on plan assets	(2,415)	(2,400)	(2,178)
Amortization of prior service cost and actuarial loss	3,478	2,373	2,646
Settlements	184	572	775
Other	(11)	956	0
Net periodic benefit cost (income)	$ 8,428	$ 9,431	$ 9,833