HISTORICAL LOSS AND LAE DEVELOPMENT (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	$ (72,481)	$ (64,583)	$ (110,061)
Casualty
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(61,805)	(40,449)	(83,892)
Casualty | Asbestos and environmental exposures
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development			1,500
Casualty | Personal umbrella
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(7,500)	(11,500)	(7,700)
Casualty | Transportation
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	3,500	3,200	(6,900)
Casualty | Executive products
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(8,900)	2,200
Casualty | General liability
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(28,500)	(14,200)	(37,300)
Casualty | Program business
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development		(9,200)	(6,200)
Casualty | Runoff casualty business
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(2,000)	(4,600)
Casualty | Commercial umbrella products
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(6,000)	(4,900)	(15,100)
Casualty | Miscellaneous professional liability
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	500
Casualty | P&C Package
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(8,100)
Property
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(7,273)	(16,800)	(18,453)
Property | Difference in conditions
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development			(7,000)
Property | Marine business
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(5,900)	(12,100)	(8,500)
Property | Other direct property products
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(3,500)	(3,500)
Property | Assumed property
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	1,400
Surety
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(3,403)	(7,334)	(7,716)
Surety | Contract surety product
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development		2,600	(3,900)
Surety | Energy surety product
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development			(2,200)
Surety | Commercial surety product
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development			$ (2,000)