Other income, net - Schedule of Components of Other Income (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Interest income and other:
Interest and dividends			$ 16.3	$ 14.4
Securities transactions, net			0.3	0.1
Total			16.6	14.5
Infrastructure reimbursement			14.6	5.1
Currency transactions, net			4.9	4.6
Insurance recoveries			1.3	2.9
Gain on land sales				1.5
Other, net			3.7	2.5
Total	$ 25.2	$ 7.5	41.1	31.1
LandWell
Interest income and other:
Infrastructure reimbursement			$ 0.4	$ 0.3