RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable prior year reserve development	$ 85,354	$ 42,115	$ 128,847	$ 96,613
Short Tail Lines Insurance And Reinsurance Business [Member]
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable prior year reserve development	73,000	32,000	101,000	62,000
Liability Reinsurance Business [Member]
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable prior year reserve development	6,000	22,000	12,000	38,000
Professional Lines Reinsurance Business [Member]
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable prior year reserve development	$ 6,000		$ 12,000