LIABILITY FOR LOSSES AND SETTELEMT EXPENSES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reconciliation of beginning and ending reserves for losses and settlement expenses [Roll Forward]
Gross reserves at beginning of year	$ 732,612	$ 690,532
Re-evaluation due to foreign currency exchange rates	525	(1,913)
Less ceded reserves at beginning of year	30,923	20,664
Net reserves at beginning of year	701,164	671,781
Incurred losses and settlement expenses related to:
Current year	116,204	111,189
Prior years	(5,576)	(14,904)
Total incurred losses and settlement expenses	110,628	96,285
Paid losses and settlement expenses related to:
Current year	24,262	22,923
Prior years	81,877	69,826
Total paid losses and settlement expenses	106,139	92,749
Net reserves at end of period	705,653	675,317
Plus ceded reserves at end of period	30,549	20,788
Re-evaluation due to foreign currency exchange rates	853	(976)
Gross reserves at end of period	737,055	695,129
Property and casualty insurance [Member]
Incurred losses and settlement expenses related to:
Prior years	$ (2,100)	$ (8,500)
Percentage change in loss and settlement expense reserves for prior accident years (in hundredths)	(0.40%)	(1.70%)
Reinsurance [Member]
Incurred losses and settlement expenses related to:
Prior years	$ (3,400)	$ (6,400)
Percentage change in loss and settlement expense reserves for prior accident years (in hundredths)	(1.50%)	(3.20%)