Reinsurance (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Mar. 31, 2021
Reinsurance Retention Policy
Catastrophe bond, face value		$ 400.0
Catastrophe
Reinsurance Retention Policy
Retention amount	$ 12.5
Earthquake events
Reinsurance Retention Policy
XOL reinsurance, protection	1,680.0
Hurricane Events
Reinsurance Retention Policy
XOL reinsurance, protection	$ 700.0