Reinsurance - Additional Information (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	Dec. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Number of reinsurers	28		28		27
Reinsurance recoverable	$ 0		$ 0		$ 0
Credit risk associated with reinsurance receivables	0		0		0
Other assets	32,545		32,545		15,814
Prepaid reinsurance premiums	30,965		30,965		28,066
Credit Concentration Risk [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Recoveries pertaining to reinsurance contracts	0	0	0	0
Reinsurance [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Net reduction in ceded premiums	6,512	5,484	17,052	6,785
Other assets	22,147		22,147		9,009
Prepaid reinsurance premiums	$ 5,941		$ 5,941		$ 3,512