Pension and Other Postretirement Benefits - Contributions for Pension and Other Postretirement Benefits (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Postretirement Benefit Plans [Member]
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Contribution	$ 182	$ 432
U.S. [Member] | Defined Benefit Pension Plan [Member]
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Contribution	0	281
U.S. [Member] | Defined Contribution Plan [Member]
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Contribution	1,402	1,377
Foreign Defined Benefits Pension Plans [Member] | Defined Benefit Pension Plan [Member]
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Contribution	171	105
U.K. [Member] | Defined Benefit Pension Plan [Member]
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Contribution	$ 82	$ 80