Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 78.5	$ 64.2
Other comprehensive income (loss), net
Foreign currency translation adjustment	17.0	(10.6)
Unrealized gains on securities:
Unrealized holding gains arising during period	0.2	1.9
Reclassification of net realized gains on investments included in net income	(0.2)	(1.9)
Other comprehensive income (loss), net	17.0	(10.6)
Comprehensive income	$ 95.5	$ 53.6