Postretirement Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	$ 126,335	$ 131,783
Interest cost	6,800	6,605	$ 6,949
Actuarial (income) loss	1,332	(2,251)
Benefits paid	(9,798)	(9,802)
Benefit obligation at end of year	124,669	126,335	131,783
Fair value of plan assets at beginning of year	126,888	137,985
Actual return on plan assets	7,956	(1,520)
Employer contributions	170	225
Benefits paid	(9,798)	(9,802)
Fair value of plan assets at end of year	125,216	126,888	137,985
Over funded status at end of year	547	553
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	12,400	13,750
Interest cost	700	647	669
Actuarial (income) loss	(170)	(1,071)
Benefits paid	(755)	(714)
Foreign exchange impact	947	(212)
Benefit obligation at end of year	13,122	12,400	13,750
Fair value of plan assets at beginning of year	14,175	16,091
Actual return on plan assets	763	(961)
Employer contributions	0	0
Benefits paid	(755)	(714)
Foreign exchange impact	1,089	(241)
Fair value of plan assets at end of year	15,272	14,175	$ 16,091
Over funded status at end of year	$ 2,150	$ 1,775