Subsequent Event - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 15, 2014 Subsequent Event [Member] Wright Insurance Group, LLC [Member]	Jan. 15, 2014 Subsequent Event [Member] Wright Insurance Group, LLC [Member] Programs Business [Member]	Jan. 15, 2014 Subsequent Event [Member] Wright Insurance Group, LLC [Member] Wright National Flood Insurance Company [Member]	Jan. 15, 2014 Subsequent Event [Member] Wright Insurance Group, LLC [Member] WNFIC Statutory Surplus [Member]
Subsequent Event [Line Items]
Aggregate purchase price of acquisitions	$ 519,794,000	$ 667,586,000	$ 214,822,000	$ 602,500,000
Cash payment for acquisition	408,072,000	483,933,000	167,444,000		587,500,000	7,500,000	7,500,000
Additional consideration in cash				$ 37,500,000