Consolidated Balance Sheets Parentheticals - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Parentheticals [Abstract]
Fixed maturity securities, amortized cost	$ 2,266.1	$ 2,333.6
Debt Securities, Available-for-sale, Allowance for Credit Loss	0.2	0.7
Equity securities, cost	212.6	112.4
Federal Home Loan Bank Stock	5.6	6.7
Other Investments, at Cost	34.1	36.8
Short-term investments, amortized cost	10.5	26.5
Premium Receivable, Allowance for Credit Loss	10.3	10.8
Reinsurance Recoverable, Allowance for Credit Loss	$ 0.6	$ 0.4
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	57,690,254	57,413,806
Common stock, shares outstanding (in shares)	27,741,400	28,564,798
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Treasury stock, at cost (in shares)	29,948,854	28,849,008