Nature of Operations - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Nature Of Operations [Line Items]
Commission percentage on aggregate replacement premium	6.00%
United [Member] | Renewal Rights Agreement [Member]
Nature Of Operations [Line Items]
Commission percentage on aggregate replacement premium	6.00%
United [Member] | Renewal Rights Agreement [Member] | Maximum [Member]
Nature Of Operations [Line Items]
Allowance paid for policy acquisition	$ 6,000
United [Member] | 85% Quota Share Reinsurance [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] | 100% Quota Share Reinsurance [Member]
Nature Of Operations [Line Items]
Quota share reinsurance percentage	100.00%
Deferred policy acquisition costs, percentage of provisional ceding commission of premium	16.00%