Postretirement Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	$ 131,783	$ 130,467
Interest cost	6,605	6,949	$ 4,923
Actuarial (income) loss	(2,251)	3,634
Benefits paid	(9,802)	(9,267)
Benefit obligation at end of year	126,335	131,783	130,467
Fair value of plan assets at beginning of year	137,985	136,744
Actual return on plan assets	(1,520)	10,237
Employer contributions	225	271
Benefits paid	(9,802)	(9,267)
Fair value of plan assets at end of year	126,888	137,985	136,744
Over funded status at end of year	553	6,202
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	13,750	13,286
Interest cost	647	669	374
Actuarial (income) loss	(1,071)	(92)
Benefits paid	(714)	(804)
Foreign exchange impact	(212)	691
Benefit obligation at end of year	12,400	13,750	13,286
Fair value of plan assets at beginning of year	16,091	15,163
Actual return on plan assets	(961)	470
Employer contributions	0	464
Benefits paid	(714)	(804)
Foreign exchange impact	(241)	798
Fair value of plan assets at end of year	14,175	16,091	$ 15,163
Over funded status at end of year	$ 1,775	$ 2,341