Pension and Postretirement Benefits other than Pensions - Net Periodic Benefit Cost of Defined Benefit Plans and Other Postretirement Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Foreign Plan [Member] | Pension Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	$ 914	$ 989
Interest cost	648	782
Expected return on plan assets	(334)	(577)
Amortization of prior service cost credit and recognized actuarial gain (loss)	932	794
Net periodic benefit (income) cost	2,160	1,988
Foreign Plan [Member] | Other Postretirement Benefits Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	90	96
Interest cost	177	173
Amortization of prior service cost credit and recognized actuarial gain (loss)	190	107
Net periodic benefit (income) cost	457	376
UNITED STATES | Pension Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	223	213
Interest cost	1,629	2,033
Expected return on plan assets	(3,564)	(3,421)
Amortization of prior service cost credit and recognized actuarial gain (loss)	418	485
Net periodic benefit (income) cost	(1,294)	(690)
UNITED STATES | Other Postretirement Benefits Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	26	26
Interest cost	133	170
Amortization of prior service cost credit and recognized actuarial gain (loss)	(349)	(483)
Net periodic benefit (income) cost	$ (190)	$ (287)