Nature of Operations - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2022
Nature Of Operations [Line Items]
Commission percentage on aggregate replacement premium	6.00%
United [Member] | HCPCI [Member]
Nature Of Operations [Line Items]
Quota share reinsurance percentage	85.00%
Deferred policy acquisition costs, percentage of provisional ceding commission of premium	25.00%
Percentage of maximum potential acquisition costs in reinsured business	32.00%
Rate of Cost Allowance	9.00%
United [Member] | Renewal Rights Agreement [Member]
Nature Of Operations [Line Items]
Commission percentage on aggregate replacement premium	6.00%