Other income, net - Schedule of Components of Other Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest income and other:
Interest and dividends			$ 11.0	$ 9.4
Securities transactions, net			0.2	0.2
Total			11.2	9.6
Gain on land sales				1.5
Currency transactions, net			2.0	8.5
Insurance recoveries			0.2	2.2
Other, net			2.5	1.8
Total	$ 3.7	$ 10.5	$ 15.9	$ 23.6