LOSS AND LOSS ADJUSTMENT EXPENSE RESERVES (Details) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Case reserves	$ 179,911,000		$ 98,815,000
IBNR	265,867,000		207,826,000
Gross balance at January 1	306,641,000	$ 305,997,000
Less: Losses recoverable	18,447,000	3,220,000	2,704,000	$ 3,368,000
Net balance at January 1	303,937,000	302,629,000
Current year	360,102,000	254,211,000
Prior years	19,644,000	29,300,000
Total incurred	379,746,000	283,511,000
Current year	(130,207,000)	(126,296,000)
Prior years	128,937,000	175,126,000
Total paid	259,144,000	301,422,000
Foreign currency revaluation	(2,792,000)	4,997,000
Net balance at September 30	427,331,000	279,721,000
Gross balance at September 30	445,778,000	282,941,000
Accident & Health
Liability for Claims and Claims Adjustment Expense [Line Items]
Gross balance at January 1	18,993,000	21,533,000
Less: Losses recoverable	0	0	$ 0	$ 0
Net balance at January 1	18,993,000	21,533,000
Current year	33,463,000	20,907,000
Prior years	2,949,000	266,000
Total incurred	36,412,000	20,641,000
Current year	(15,019,000)	(9,150,000)
Prior years	18,832,000	11,646,000
Total paid	33,851,000	20,796,000
Foreign currency revaluation	0	0
Net balance at September 30	21,554,000	21,378,000
Gross balance at September 30	$ 21,554,000	$ 21,378,000