Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Fixed maturities, at amortized cost	$ 7,622.5	$ 7,811.8
Fixed maturities, allowance for credit losses	8.6	9.6
Equity securities, at cost	215.5	247.6
Premium receivables, allowance for credit losses	13.5	13.1
Long-term Debt	$ 1,158.0	$ 1,195.1
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	64,081,099	63,912,762
Common stock, shares outstanding (in shares)	64,081,099	63,912,762
Variable Interest Entity, Primary Beneficiary
Fixed maturities, at amortized cost	$ 1.6	$ 0.0
Fixed maturities, allowance for credit losses	$ 0.0	$ 0.0