Summary of Significant Accounting Policies - Reinsurance - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Ceded Credit Risk [Line Items]
Amount of allowance for uncollectible amounts on paid recoverables	$ 16,100,000	$ 16,100,000
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	10,983,000	$ 11,188,000
Financing receivable, allowance for credit Loss, write-off	0
Amount of allowance for uncollectible amounts due beyond one year	$ 0
Threshold period for including reinsurance receivables in the allowance for uncollectible amounts	1 year
Maximum
Ceded Credit Risk [Line Items]
Financing receivable, allowance for credit loss, recovery	$ 100,000