Goodwill (Carrying Amount of Goodwill by Reportable Segment) (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 1,807.5
Acquisitions	1.3
Foreign currency translation	(1.5)
Balance at end of period	1,807.3
Title Insurance and Services
Goodwill [Line Items]
Balance at beginning of period	1,766.6
Acquisitions	1.3
Foreign currency translation	(1.5)
Balance at end of period	1,766.4
Home Warranty
Goodwill [Line Items]
Balance at beginning of period	40.9
Acquisitions	0.0
Foreign currency translation	0.0
Balance at end of period	$ 40.9