Postretirement Benefit Plans - Schedule of Amounts Recognized in Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset	$ 7,166	$ 3,470
Current liability	(290)	(288)
Non-current liability	(3,165)	(15,217)
Net amount recognized	3,711	(12,035)
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset	4,188	2,978
Net amount recognized	$ 4,188	$ 2,978