Liability for Unpaid Losses and Loss Adjustment Expenses - Change in Liability for Unpaid Losses and LAE (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance at beginning of period	$ 288,296	$ 151,916	$ 472,829	$ 248,425
Less: Reinsurance recoverable	(197,117)	(96,733)	(393,365)	(182,405)
Net balance at beginning of period	91,179	55,183	79,464	66,020
Incurred (recovered) related to current year	129,353	85,986	355,258	249,488
Incurred (recovered) related to prior years	3,218	(39)	3,703	2,227
Total incurred	132,571	85,947	358,961	251,715
Paid related to Current year	137,313	72,034	260,955	140,013
Paid related to Prior years	30,408	38,372	121,441	146,998
Total paid	167,721	110,406	382,396	287,011
Net balance at end of period	56,029	30,724	56,029	30,724
Plus: Reinsurance recoverable	(110,313)	(127,943)	(110,313)	(127,943)
Balance at end of period	$ 166,342	$ 158,667	$ 166,342	$ 158,667

The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

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Amount, after effects of reinsurance, of payments to settle claims incurred in the current period and related claims settlement costs.

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Amount, after effects of reinsurance, of payments to settle claims incurred in prior periods and related claims settlement costs.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred and costs incurred in the claim settlement process.

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Liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount, after effects of reinsurance, of payments to settle insured claims and pay costs incurred in the claims settlement process.

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Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

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Amount, after effects of reinsurance, of expense for claims incurred in the current reporting period and related claims settlement costs.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs.

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