Subordinated Debt Securities - Additional Information (Detail) (USD $)	0 Months Ended		1 Months Ended			12 Months Ended				0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended
	Apr. 29, 2004	Dec. 16, 2003	Aug. 31, 2012	May 31, 2012	Jul. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 16, 2003 Amerisafe Capital Trust I [Member]	Dec. 31, 2013 Amerisafe Capital Trust I [Member]	Apr. 29, 2004 Amerisafe Capital Trust II [Member]	Dec. 31, 2013 Amerisafe Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Purchase of subordinated debt securities	$ 25,800,000	$ 10,300,000
Preferred securities to investors	25,000,000	10,000,000								10,000,000		25,000,000
Common securities to the Company										300,000		800,000
Redemption of debt securities			$ 12,900,000	$ 12,900,000	$ 10,300,000	$ 25,780,000	$ 10,310,000
Subordinated debt securities quarterly rate											LIBOR plus 4.10%		LIBOR plus 3.80% per annum
Debt securities interest rate	3.80%	4.10%					4.30%	4.40%
Subordinated debt securities due									2034