Liability for Unpaid Losses and Loss Adjustment Expenses - Change in Liability for Unpaid Losses and LAE (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance at beginning of period	$ 366,356	$ 129,637	$ 472,829	$ 248,425
Less: Reinsurance recoverable	(269,071)	(70,351)	(393,365)	(182,405)
Net balance at beginning of period	97,285	59,286	79,464	66,020
Incurred (recovered) related to current year	112,626	87,532	225,905	163,502
Incurred (recovered) related to prior years	670	2,310	485	2,266
Total incurred	113,296	89,842	226,390	165,768
Paid related to Current year	89,093	50,572	123,642	67,979
Paid related to Prior years	30,309	43,373	91,033	108,626
Total paid	119,402	93,945	214,675	176,605
Net balance at end of period	91,179	55,183	91,179	55,183
Plus: Reinsurance recoverable	(197,117)	(96,733)	(197,117)	(96,733)
Balance at end of period	$ 288,296	$ 151,916	$ 288,296	$ 151,916

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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