CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Fixed maturities available-for-sale, amortized cost	$ 673.5	$ 696.8
Short term investments, cost	99.9	110.4
Premium receivable, allowance for doubtful accounts	$ 2.7	$ 1.6
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	69,275,030	61,660,996
Common stock, outstanding (in shares)	69,275,030	61,660,996