Losses and Loss Adjustment Expenses - Liability for Unpaid Losses and Loss Adjustment Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, beginning of period	$ 53,271	$ 51,177	$ 51,690	$ 48,908
Incurred related to:
Current period	20,803	20,222	47,420	39,054
Prior period	5,469	343	5,932	550
Total incurred	26,272	20,565	53,352	39,604
Paid related to:
Current period	(14,239)	(10,256)	(22,596)	(15,052)
Prior period	(10,577)	(7,157)	(27,719)	(19,131)
Total paid	(24,816)	(17,413)	(50,315)	(34,183)
Balance, end of period	$ 54,727	$ 54,329	$ 54,727	$ 54,329