TRANSACTIONS WITH AFFILIATES (Details) - Affiliated Entity [Member] $ in Thousands	3 Months Ended		6 Months Ended				12 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2018 USD ($) Plan	Jun. 30, 2018 USD ($) Plan	Dec. 31, 2017 USD ($) Plan	Jun. 30, 2017 USD ($) Plan	Dec. 31, 2018 USD ($) Plan	Dec. 31, 2017 USD ($) Plan
Related Party Transaction [Line Items]
Ceded premiums earned	$ 103,303	$ 99,568		$ 203,341		$ 199,659
Ceded losses and settlement expenses incurred	62,677	88,813		$ 114,678		$ 152,156
Property and casualty insurance [Member]
Related Party Transaction [Line Items]
Number of reinsurance program treaties | Plan			1	1	1	1	2	2
Ceded premiums earned	101,991	98,356		$ 200,716		$ 197,234
Ceded losses and settlement expenses incurred	62,386	88,812		115,140		152,146
Property and casualty insurance [Member] | Annual Aggregate Catastrophe Excess of Loss [Member]
Related Party Transaction [Line Items]
Catastrophe claims, retention amount			$ 15,000	22,000	$ 15,000	20,000
Affiliated reinsurance contract first layer limit			12,000	24,000	12,000	24,000
Ceded premiums earned			$ 1,400	6,000	$ 1,400	6,000
Ceded losses and settlement expenses incurred	317	16,001		784		16,574
Reinsurance [Member]
Related Party Transaction [Line Items]
Number of reinsurance program treaties | Plan							2	2
Ceded premiums earned	1,312	1,212		2,625		2,425
Ceded losses and settlement expenses incurred	$ 291	$ 1		$ (462)		$ 10
Reinsurance [Member] | Per Occurrence Catastrophe Excess of Loss [Member]
Related Party Transaction [Line Items]
Catastrophe claims, retention amount							$ 10,000	$ 10,000
Affiliated reinsurance contract first layer limit							$ 10,000	$ 10,000
First layer excess of loss coinsurance percentage (in hundreths)							20.00%	20.00%
Ceded premiums earned							$ 1,600	$ 1,700
Reinsurance [Member] | Annual Aggregate Catastrophe Excess of Loss [Member]
Related Party Transaction [Line Items]
Catastrophe claims, retention amount							20,000	20,000
Affiliated reinsurance contract first layer limit							$ 100,000	$ 100,000
First layer excess of loss coinsurance percentage (in hundreths)							20.00%	20.00%
Ceded premiums earned							$ 3,600	$ 3,200
Catastrophe event minimum amount							$ 500	$ 500