Commitments and Contingent Liabilities - Schedule of Black Lung Benefit Liabilities (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) claim	Dec. 31, 2023 USD ($) claim
Loss Contingencies [Line Items]
Current portion of black lung liability	$ 1.2	$ 5.0
Black lung Benefit
Loss Contingencies [Line Items]
Discount rate (as a percent)	4.50%	4.50%
Loss Contingency, Pending Claims, Number | claim	53	311
Total black lung liability, discounted	$ 14.4	$ 58.2
Total black lung liability, undiscounted	$ 27.1	$ 96.0
Decrease in discount rate	0.0025	0.0025
Decrease in discount rate resulting in increase in black lung expense	$ 0.4	$ 1.4
Current portion of black lung liability	$ 1.2	$ 5.9