Postretirement Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	$ 174,863	$ 187,371
Interest cost	4,923	4,671	$ 5,668
Actuarial income	(40,420)	(8,682)
Benefits paid	(8,899)	(8,497)
Benefit obligation at end of year	130,467	174,863	187,371
Fair value of plan assets at beginning of year	178,574	175,336
Actual return on plan assets	(33,187)	11,459
Employer contributions	256	276
Benefits paid	(8,899)	(8,497)
Fair value of plan assets at end of year	136,744	178,574	175,336
Over funded status at end of year	6,277	3,711
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	23,276	25,526
Interest cost	374	357	445
Actuarial income	(7,333)	(1,171)
Benefits paid	(709)	(1,198)
Foreign exchange impact	(2,322)	(238)
Benefit obligation at end of year	13,286	23,276	25,526
Fair value of plan assets at beginning of year	27,464	28,504
Actual return on plan assets	(9,393)	(78)
Employer contributions	536	526
Benefits paid	(709)	(1,198)
Foreign exchange impact	(2,735)	(290)
Fair value of plan assets at end of year	15,163	27,464	$ 28,504
Over funded status at end of year	$ 1,877	$ 4,188