Summary of Significant Accounting Policies Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill	$ 174.0	$ 160.7
Acquisitions	1.1	13.2
Impairments	0.0	0.0
Goodwill	175.1	174.0
General Insurance Segment [Member]
Goodwill [Roll Forward]
Goodwill	116.2	116.2
Acquisitions	0.0	0.0
Impairments	0.0	0.0
Goodwill	116.2	116.2
Title Insurance Group [Member]
Goodwill [Roll Forward]
Goodwill	57.5	44.3
Acquisitions	1.1	13.2
Impairments	0.0	0.0
Goodwill	58.7	57.5
RFIG Run-off Business [Member]
Goodwill [Roll Forward]
Goodwill	0.0	0.0
Acquisitions	0.0	0.0
Impairments	0.0	0.0
Goodwill	0.0	0.0
Corporate & Other [Member]
Goodwill [Roll Forward]
Goodwill	0.1	0.1
Acquisitions	0.0	0.0
Impairments	0.0	0.0
Goodwill	$ 0.1	$ 0.1

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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