Marketable Securities - Schedule of Marketable Securities (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Marketable Securities [Line Items]
Market value, current	$ 83.2	$ 75.1
Market value, noncurrent	3.2	1.2
Noncurrent assets
Marketable Securities [Line Items]
Market value, noncurrent	3.2	1.2
Cost or amortized cost	3.6	1.2
Unrealized loss, net	(0.4)	0.0
Current assets
Marketable Securities [Line Items]
Market value, current	83.2	75.1
Cost or amortized cost	83.4	75.7
Unrealized loss, net	$ (0.2)	$ (0.6)