RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	$ 292,377	$ 243,048	$ 258,944
Insurance [Member]
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	55,905	23,447	63,735
Reinsurance [Member]
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	$ 236,472	$ 219,601	$ 195,209