HISTORICAL LOSS AND LAE DEVELOPMENT (Details 2) - 10K (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	$ (64,842)	$ (72,481)	$ (64,583)
Casualty segment
(Favorable)/unfavorable reserve development
Number of years			2 years
(Favorable)/unfavorable reserve development	(52,825)	(61,805)	(40,449)
Casualty segment | Personal umbrella
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(800)	(7,500)	(11,500)
Casualty segment | Commercial transportation
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development		3,500	3,200
Casualty segment | Executive products
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development		(8,900)	2,200
Casualty segment | General liability
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(28,100)	(28,500)	(14,200)
Casualty segment | Specialty programs
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development			(9,200)
Casualty segment | Runoff casualty business
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(900)	(2,000)	(4,600)
Casualty segment | Commercial products
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(4,400)	(6,500)	(4,900)
Casualty segment | Miscellaneous Professional Liability Member
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development		500
Casualty segment | P&C Package
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(9,400)	(8,100)
Property segment
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(1,123)	(7,273)	(16,800)
Property segment | Marine
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(5,800)	(5,900)	(12,100)
Property segment | Other direct property products
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development		(3,500)	(3,500)
Property segment | Assumed property
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	4,000	1,400
Property segment | Crop Member
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	1,200
Surety segment
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(10,894)	(3,403)	(7,334)
Surety segment | Contract surety product
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(4,600)		2,600
Surety segment | Oil and Gas Surety Product Member
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(1,200)
Surety segment | Commercial surety product
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	(4,300)
Surety segment | Miscellaneous Surety Product Member
(Favorable)/unfavorable reserve development
(Favorable)/unfavorable reserve development	$ (900)