LIABILITY FOR LOSSES AND SETTELEMT EXPENSES (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Reconciliation of beginning and ending reserves for losses and settlement expenses [Roll Forward]
Gross reserves at beginning of year	$ 690,532	$ 678,774
Re-evaluation due to foreign currency exchange rates	(1,913)	(2,475)
Less ceded reserves at beginning of year	20,664	23,477
Net reserves at beginning of year	671,781	657,772
Incurred losses and settlement expenses related to:
Current year	340,706	325,211
Prior years	(17,617)	(29,109)
Total incurred losses and settlement expenses	323,089	296,102
Paid losses and settlement expenses related to:
Current year	120,053	112,283
Prior years	173,986	161,888
Total paid losses and settlement expenses	294,039	274,171
Net reserves at end of period	700,831	679,703
Plus ceded reserves at end of period	25,348	21,983
Re-evaluation due to foreign currency exchange rates	282	(1,121)
Gross reserves at end of period	726,461	700,565
Property and casualty insurance [Member]
Incurred losses and settlement expenses related to:
Prior years	$ (15,600)	$ (22,200)
Percentage change in loss and settlement expense reserves for prior accident years (in hundredths)	(3.20%)	(3.50%)
Adjustment for favorable development included in the reported development amount that had no impact on earnings		$ 5,600
Approximation of the implied amount of favorable development that had an impact on earnings		16,600
Reinsurance [Member]
Incurred losses and settlement expenses related to:
Prior years	$ (2,100)	$ (6,900)
Percentage change in loss and settlement expense reserves for prior accident years (in hundredths)	(1.00%)	(3.50%)