Reinsurance - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Effects of Reinsurance [Line Items]
Reinsurance, excess loss coverage threshold	$ 0.6	$ 0.5	$ 0.5
Coinsurance percentage				100.00%
Life insurance reserves, fully coinsured by third party		5.3		$ 5.3
Life insurance reserves, coinsurance percentage				100.00%
Annuity reserve, fully ceded to third party		$ 0.9		$ 0.9
Annuity reserves, transfer of risk percentage				100.00%
Minimum
Effects of Reinsurance [Line Items]
Life insurance reserves assumption, interest rate				1.00%
Annuity reserves assumption, interest rate				1.00%
Maximum
Effects of Reinsurance [Line Items]
Life insurance reserves assumption, interest rate				4.50%
Annuity reserves assumption, interest rate				5.80%