RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Beginning and Ending Gross Unpaid Losses and Loss Expenses
Gross reserve for losses and loss expenses, beginning of year	$ 9,646,285	$ 9,596,797	$ 9,582,140
Less reinsurance recoverable on unpaid losses, beginning of year	(2,031,309)	(1,890,280)	(1,900,112)
Net reserve for unpaid losses and loss expenses, beginning of year	7,614,976	7,706,517	7,682,028
Net incurred losses and loss expenses related to:
Current year	2,496,574	2,419,247	2,445,666
Prior years	(292,377)	(243,048)	(258,944)
Net incurred losses and loss expenses	2,204,197	2,176,199	2,186,722
Net paid losses and loss expenses related to:
Current year	(428,153)	(343,063)	(387,197)
Prior years	(1,763,696)	(1,709,659)	(1,544,664)
Net paid losses and loss expenses	(2,191,849)	(2,052,722)	(1,931,861)
Foreign exchange and other	(205,606)	(215,018)	(230,372)
Net reserve for unpaid losses and loss expenses, end of year	7,421,718	7,614,976	7,706,517
Reinsurance recoverable on unpaid losses, end of year	2,276,109	2,031,309	1,890,280
Gross reserve for losses and loss expenses, end of year	$ 9,697,827	$ 9,646,285	$ 9,596,797