Postretirement Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	$ 187,371	$ 176,499
Interest cost	4,671	5,668	$ 6,616
Actuarial loss (income)	(8,682)	13,327
Benefits paid	(8,497)	(8,123)
Benefit obligation at end of year	174,863	187,371	176,499
Fair value of plan assets at beginning of year	175,336	160,423
Actual return on plan assets	11,459	22,738
Employer contributions	276	298
Benefits paid	(8,497)	(8,123)
Fair value of plan assets at end of year	178,574	175,336	160,423
Over (Under) funded status at end of year	3,711	(12,035)
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	25,526	21,850
Interest cost	357	445	554
Actuarial loss (income)	(1,171)	3,032
Benefits paid	(1,198)	(657)
Foreign exchange impact	(238)	856
Benefit obligation at end of year	23,276	25,526	21,850
Fair value of plan assets at beginning of year	28,504	24,357
Actual return on plan assets	(78)	3,320
Employer contributions	526	526
Benefits paid	(1,198)	(657)
Foreign exchange impact	(290)	958
Fair value of plan assets at end of year	27,464	28,504	$ 24,357
Over (Under) funded status at end of year	$ 4,188	$ 2,978