Other Nonoperating Income, Net - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Component of Other Operating Income and Expense [Line Items]
Other nonoperating income, net	$ 62.1	$ 53.4	$ 24.4
Other Nonoperating Income, Net
Component of Other Operating Income and Expense [Line Items]
Gain on repurchase of bond		12.0
Interest income	46.7	13.6
Third-party railroad track maintenance expense	$ 8.9	$ 8.2	$ 7.7