Business Combinations - Additions, Payments, and Net Changes, as well as Interest Expense Accretion on Estimated Acquisition Earn-Out Payables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Business Combinations [Abstract]
Beginning balance	$ 232.9	$ 242.0	$ 291.0	$ 258.9
Additions to estimated acquisition earn-out payables	25.2		42.1	25.2
Assumed acquisition earn-out payables	34.8		34.8
Payments for estimated acquisition earn-out payables	(10.6)	(1.9)	(77.1)	(41.8)
Subtotal	282.3	240.1	290.8	242.3
Net change in earnings from estimated acquisition earn-out payables:
Change in fair value on estimated acquisition earn-out payables	(28.5)	21.8	(38.1)	15.8
Interest expense accretion	1.9	1.3	5.0	4.8
Net change in earnings from estimated acquisition earn-out payables	(26.6)	23.1	(33.1)	20.6
Foreign currency translation adjustments during the year	(5.8)	(0.3)	(7.8)
Ending balance	$ 249.9	$ 262.9	$ 249.9	$ 262.9