Losses and Loss Adjustment Expenses Incurred and Paid - Information Regarding the Reserve for Unpaid Losses and Loss Adjustment Expenses (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Insurance [Abstract]
Liability for unpaid losses and LAE at beginning of period, gross	$ 122,071	$ 96,613
Reinsurance balances receivable, beginning balance	(464)	(362)
Liability for unpaid losses and LAE at beginning of period, net	121,607	96,251
Add: Provision for losses and LAE:
Current period	143,173	104,624
Prior periods	31,011	(1,687)
Net losses and LAE incurred	174,184	102,937
Less: Losses and LAE paid:
Current period	58,750	46,872
Prior periods	71,703	42,293
Net losses and LAE paid	130,453	89,165
Liability for unpaid losses and LAE at end of period, net	165,338	110,023
Reinsurance balances receivable, ending balance	674	453
Liability for unpaid losses and LAE at end of period, gross	$ 166,012	$ 110,476