RESERVE FOR LOSSES AND LOSS EXPENSES (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	$ 47,768	$ 76,019	$ 143,495	$ 224,131
Insurance [Member]
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	2,603	20,688	30,740	43,181
Reinsurance [Member]
Net Favorable Prior Year Reserve Development [Line Items]
Net favorable prior year reserve development	$ 45,165	$ 55,331	$ 112,755	$ 180,950