Summary of Significant Accounting Policies Revenue Recognition (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Title Premium And Fee Revenues Stemming From Direct Operations	21.00%	19.50%	22.00%
Non-insurance Contract Revenue	$ 215.9	$ 210.1	$ 210.2
General Insurance Group [Member]
Contract Revenue - Claims Handling and Related Ancillary Services	145.1	132.8	127.0
Title Insurance Group [Member]
Non-insurance Contract Title Services	$ 62.5	$ 69.2	$ 75.6