Income Taxes - Components of Pretax Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of income before provision for income taxes and noncontrolling interest
Domestic	$ 340.4	$ 509.5	$ 264.6
Foreign	8.6	26.8	45.5
Income before income taxes and loss from equity method investment	349.0	536.3	310.1
Current provision (benefit):
Federal	219.0	223.6	63.4
States	25.9	23.9	15.9
Foreign	46.5	36.2	48.2
Total current provision (benefit)	291.4	283.7	127.5
Deferred (benefit) provision:
Federal	(250.0)	(199.3)	(54.3)
States	(13.6)	(13.6)	(4.1)
Foreign	1.4	(10.3)	(11.7)
Total deferred (benefit) provision	(262.2)	(223.2)	(70.1)
Total provision for income taxes	29.2	60.5	57.4
Income tax reconciliation
Expected provision at statutory rate	73.3	112.7	65.1
State taxes, net of federal benefit	7.0	12.0	6.5
Foreign income at different tax rates	(24.4)	(18.1)	(0.2)
R&D tax credits	(31.4)	(23.6)	(16.6)
Share-based compensation	(5.2)	(7.4)	(2.2)
Non-deductible compensation	5.1	4.0	4.2
Recognition of previously unrecognized tax benefits	0.0	(8.1)	0.0
Other	4.8	(11.0)	0.6
Total provision for income taxes	$ 29.2	$ 60.5	$ 57.4