Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 45	$ (610)	$ (28)
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	6,800	6,605	6,949
Expected return on plan assets	(8,009)	(8,479)	(8,533)
Amortization of net actuarial (gain) loss	(76)	(12)	(23)
Net periodic benefit cost	(1,285)	(1,886)	(1,607)
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	700	647	669
Expected return on plan assets	(811)	(735)	(695)
Amortization of net actuarial (gain) loss	383	324	334
Net periodic benefit cost	$ 272	$ 236	$ 308