Schedule II – Condensed Financial Statements (Parent Only) - Balance Sheet (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Fixed maturity securities available for sale, amortized cost	$ 6,903.9
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	800,000,000	800,000,000
Common stock shares issued (in shares)	58,050,202	62,967,808
Common stock, shares outstanding (in shares)	55,754,113	57,967,808	59,945,893	61,908,979
Treasury stock, at cost (in shares)	2,296,089	5,000,000
Parent Company
Condensed Financial Statements, Captions [Line Items]
Fixed maturity securities available for sale, amortized cost	$ 879.4	$ 127.6
Preferred stock, dividend rate	6.50%	6.50%
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized (in shares)	0	2,875,000
Preferred stock, shares issued (in shares)	0	2,875,000
Preferred stock, shares outstanding (in shares)	0	2,875,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	800,000,000	800,000,000
Common stock shares issued (in shares)	58,050,202	62,967,808
Common stock, shares outstanding (in shares)	55,754,113	57,967,808
Treasury stock, at cost (in shares)	2,296,089	5,000,000