Losses and Loss Adjustment Expenses - Liability for Unpaid Losses and Loss Adjustment Expenses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance, beginning of period	$ 43,044	$ 44,749	$ 43,686	$ 41,168
Incurred related to:
Current period	21,643	14,851	59,205	50,213
Prior period	348	(362)	(266)	(2,438)
Total incurred	21,991	14,489	58,939	47,775
Paid related to:
Current period	(3,461)	(12,628)	(22,296)	(25,880)
Prior period	(13,920)	(3,086)	(32,675)	(19,539)
Total paid	(17,381)	(15,714)	(54,971)	(45,419)
Balance, end of period	$ 47,654	$ 43,524	$ 47,654	$ 43,524