RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	$ 257,461	$ 313,055	$ 423,172
Insurance [Member]
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	103,014	118,336	210,861
Reinsurance [Member]
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	$ 154,447	$ 194,719	$ 212,311