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Reinsurance (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Effects Of Reinsurance [Line Items]
Property and casualty premiums earned, Ceded	$ 691.6	$ 659.9	$ 629.4
Property and casualty losses and LAE, Ceded	388.2	419.1	397.3
Reinsurance recoverable on paid and unpaid losses and unearned premiums	2,011.1	1,994.5
MCCA [Member]
Effects Of Reinsurance [Line Items]
Property and casualty premiums earned, Ceded	29.7	39.2	32.9
Property and casualty losses and LAE, Ceded	35.2	60.0	$ 72.8
Reinsurance recoverable on paid and unpaid losses and unearned premiums	$ 829.2	$ 870.4
MCCA [Member] | Reinsurance Receivable [Member] | Reinsurer Concentration Risk [Member]
Effects Of Reinsurance [Line Items]
Percentage of reinsurance receivable represented by segment	41.20%

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Amount of earned premiums ceded to other entities.

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