Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Goodwill [Roll Forward]
Beginning balance	$ 4,511.8	$ 4,537.0
Disposed	(15.0)	0.0
Effect of foreign currency translation and other adjustments	17.1	(25.2)
Ending balance	4,668.0	4,511.8
JM Wood Auction Co Inc
Goodwill [Roll Forward]
Acquired	145.8	0.0
Smith Broughton Pty Ltd
Goodwill [Roll Forward]
Acquired	$ 8.3	$ 0.0