Retirement Benefit Plans - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Postretirement Medical Benefits
Defined Benefit Plan, Plan Assets, Category [Line Items]
Net actuarial loss	$ 1.1	$ 0.1	$ (0.7)
Foreign exchange	0.0	0.0	0.0
Amortization of net actuarial (loss) gain	0.3	0.3	0.2
Amounts recorded in other comprehensive income	1.4	0.4	(0.5)
UNITED STATES | Supplemental Employee Retirement Plan
Defined Benefit Plan, Plan Assets, Category [Line Items]
Net actuarial loss	0.1	0.1	0.1
Foreign exchange	0.0	0.0	0.0
Amortization of net actuarial (loss) gain	(0.1)	(0.1)	(0.1)
Amounts recorded in other comprehensive income	0.0	0.0	0.0
Non-U.S. Plan | Pension Plan
Defined Benefit Plan, Plan Assets, Category [Line Items]
Net actuarial loss	0.8	0.8	(0.9)
Foreign exchange	(0.2)	0.1	0.0
Amortization of net actuarial (loss) gain	0.1	0.1	0.1
Amounts recorded in other comprehensive income	$ 0.7	$ 1.0	$ (0.8)