Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 116.4	$ 136.4	$ 163.1	$ 182.4
Other comprehensive income (loss), net of tax:
Unrealized (losses) gains on debt securities	(5.8)	(79.7)	(56.4)	30.4
Foreign currency translation adjustment	(3.8)	11.2	(18.3)	13.8
Pension benefit adjustment	0.4	0.4	0.8	0.7
Total other comprehensive income, net of tax	(9.2)	(68.1)	(73.9)	44.9
Comprehensive income	107.2	68.3	89.2	227.3
Less: Comprehensive income (loss) attributable to noncontrolling interests	0.4	(2.1)	0.4	(2.0)
Comprehensive income attributable to the Company	$ 106.8	$ 70.4	$ 88.8	$ 229.3