Business Combinations - Additions, Payments, and Net Changes, as well as Interest Expense Accretion on Estimated Acquisition Earn-Out Payables (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Combinations [Abstract]
Beginning balance	$ 291.0	$ 258.9	$ 161.5
Additions to estimated acquisition earn-out payables from new acquisitions	73.3	75.8	131.4
Assumed estimated acquisition earn-out payables	34.8
Payments for estimated acquisition earn-out payables	(106.3)	(83.6)	(29.5)
Subtotal	292.8	251.1	263.4
Net change in earnings from estimated acquisition earn-out payables:
Change in fair value on estimated acquisition earn-out payables	(45.9)	34.2	(11.8)
Interest expense accretion	7.0	6.2	7.3
Net change in earnings from estimated acquisition earn- out payables	(38.9)	40.4	(4.5)
Foreign currency translation adjustments during the year	(2.3)	(0.5)
Ending balance	$ 251.6	$ 291.0	$ 258.9