Postretirement Benefit Plans - Schedule of Amounts Recognized in Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset	$ 8,627	$ 8,700
Current liability	(308)	(278)
Non-current liability	(2,117)	(2,145)
Net amount recognized	6,202	6,277
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset	2,341	1,877
Net amount recognized	$ 2,341	$ 1,877