Postretirement Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (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]
Net actuarial (gain) loss	$ 7,748	$ 1,930	$ 1,570
Amortization of net actuarial gain (loss)	12	23	(2,277)
Total recognized in other comprehensive income	7,760	1,953	(707)
Total recognized in net periodic benefit cost and other comprehensive income	5,874	346	(2,309)
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial (gain) loss	618	135	2,430
Amortization of net actuarial gain (loss)	(324)	(334)	(9)
Total recognized in other comprehensive income	294	(199)	2,421
Total recognized in net periodic benefit cost and other comprehensive income	$ 530	$ 109	$ 2,405