REINSURANCE (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Premiums written
Net premiums written	$ 144,875	$ 142,276
Premiums earned
Net premiums earned	144,487	142,737
Losses and settlement expenses incurred
Net losses and settlement expenses incurred		85,109
Affiliated Entity [Member]
Premiums written
Assumed	124,800	118,846
Ceded	(100,944)	(99,411)
Premiums earned
Assumed	122,097	118,262
Ceded	(100,091)	(97,261)
Losses and settlement expenses incurred
Assumed	77,106	61,842
Ceded	(63,343)	(40,726)
Non Affiliated Entity [Member]
Premiums written
Direct	96,752	94,986
Assumed	34,424	35,216
Ceded	(10,157)	(7,361)
Premiums earned
Direct	95,898	92,836
Assumed	35,704	35,743
Ceded	(9,121)	(6,843)
Losses and settlement expenses incurred
Direct	62,761	41,054
Assumed	21,992	23,923
Ceded	$ (2,231)	$ (984)
Property and casualty insurance [Member]
Reinsurance Transactions For Insurance Companies, by Product Segment [Line Items]
Percentage of pool participation (in hundredths)	30.00%	30.00%
Premiums written
Net premiums written	$ 114,607	$ 111,267
Premiums earned
Net premiums earned	113,648	110,446
Losses and settlement expenses incurred
Net losses and settlement expenses incurred	75,520	62,098
Property and casualty insurance [Member] | Affiliated Entity [Member]
Premiums written
Assumed	124,800	118,846
Ceded	(99,731)	(98,141)
Premiums earned
Assumed	122,097	118,262
Ceded	(98,878)	(95,991)
Losses and settlement expenses incurred
Assumed	76,742	61,454
Ceded	(63,334)	(41,054)
Property and casualty insurance [Member] | Non Affiliated Entity [Member]
Premiums written
Direct	96,752	94,986
Assumed	919	957
Ceded	(8,133)	(5,381)
Premiums earned
Direct	95,898	92,836
Assumed	1,015	1,027
Ceded	(6,484)	(5,688)
Losses and settlement expenses incurred
Direct	62,761	41,054
Assumed	752	721
Ceded	(1,401)	(77)
Reinsurance [Member]
Premiums written
Net premiums written	30,268	31,009
Premiums earned
Net premiums earned	30,839	32,291
Losses and settlement expenses incurred
Net losses and settlement expenses incurred	20,765	23,011
Reinsurance [Member] | Affiliated Entity [Member]
Premiums written
Assumed	0	0
Ceded	(1,213)	(1,270)
Premiums earned
Assumed	0	0
Ceded	(1,213)	(1,270)
Losses and settlement expenses incurred
Assumed	364	388
Ceded	(9)	328
Reinsurance [Member] | Non Affiliated Entity [Member]
Premiums written
Direct	0	0
Assumed	33,505	34,259
Ceded	(2,024)	(1,980)
Premiums earned
Direct	0	0
Assumed	34,689	34,716
Ceded	(2,637)	(1,155)
Losses and settlement expenses incurred
Direct	0	0
Assumed	21,240	23,202
Ceded	$ (830)	$ (907)