INVESTMENTS Unrealized Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investment positions with unrealized losses
Unrealized losses relative to total invested assets (as a percent)	0.60%
Fair value
Less than 12 months	$ 138,463	$ 500,405
12 Months and Greater	79,866	44,476
Total Fair value	218,329	544,881
Cost or amortized Cost
Less than 12 months	143,829	514,250
12 months and greater	86,543	49,883
Total Cost or Amortized Cost	230,372	564,133
Unrealized Loss
Less than 12 months	(5,366)	(13,845)
12 Months and Greater	(6,677)	(5,407)
Total Unrealized Loss	(12,043)	(19,252)
Debt securities
Fair value
Less than 12 months	129,839	483,929
12 Months and Greater	79,866	44,476
Total Fair value	209,705	528,405
Cost or amortized Cost
Less than 12 months	134,434	496,318
12 months and greater	86,543	49,883
Total Cost or Amortized Cost	220,977	546,201
Unrealized Loss
Less than 12 months	(4,595)	(12,389)
12 Months and Greater	(6,677)	(5,407)
Total Unrealized Loss	$ (11,272)	(17,796)
Percent to Total	100.00%
Debt securities | NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Fair value
Total Fair value	$ 101,196
Cost or amortized Cost
Total Cost or Amortized Cost	102,457
Unrealized Loss
Total Unrealized Loss	$ (1,261)
Percent to Total	11.20%
Debt securities | NAIC Rating 2 | BBB | Baa
Fair value
Total Fair value	$ 55,757
Cost or amortized Cost
Total Cost or Amortized Cost	58,657
Unrealized Loss
Total Unrealized Loss	$ (2,900)
Percent to Total	25.70%
Debt securities | NAIC Rating 3 | BB | Ba
Fair value
Total Fair value	$ 18,745
Cost or amortized Cost
Total Cost or Amortized Cost	21,337
Unrealized Loss
Total Unrealized Loss	$ (2,592)
Percent to Total	23.00%
Debt securities | NAIC Rating 4 | B
Fair value
Total Fair value	$ 32,230
Cost or amortized Cost
Total Cost or Amortized Cost	35,942
Unrealized Loss
Total Unrealized Loss	$ (3,712)
Percent to Total	32.90%
Debt securities | NAIC Rating 5 | CCC or lower
Fair value
Total Fair value	$ 1,777
Cost or amortized Cost
Total Cost or Amortized Cost	2,584
Unrealized Loss
Total Unrealized Loss	$ (807)
Percent to Total	7.20%
U.S. government
Fair value
Less than 12 months		36,000
Total Fair value		36,000
Cost or amortized Cost
Less than 12 months		36,112
Total Cost or Amortized Cost		36,112
Unrealized Loss
Less than 12 months		(112)
Total Unrealized Loss		(112)
U.S. Agency
Fair value
Less than 12 months	$ 4,001	8,070
Total Fair value	4,001	8,070
Cost or amortized Cost
Less than 12 months	4,002	8,117
Total Cost or Amortized Cost	4,002	8,117
Unrealized Loss
Less than 12 months	(1)	(47)
Total Unrealized Loss	(1)	(47)
Non-U.S. govt. & agency
Fair value
Less than 12 months	3,737	4,478
Total Fair value	3,737	4,478
Cost or amortized Cost
Less than 12 months	4,054	5,035
Total Cost or Amortized Cost	4,054	5,035
Unrealized Loss
Less than 12 months	(317)	(557)
Total Unrealized Loss	(317)	(557)
Agency MBS
Fair value
Less than 12 months	5,779	100,424
12 Months and Greater	25,039	18,520
Total Fair value	30,818	118,944
Cost or amortized Cost
Less than 12 months	5,815	101,473
12 months and greater	25,301	19,090
Total Cost or Amortized Cost	31,116	120,563
Unrealized Loss
Less than 12 months	(36)	(1,049)
12 Months and Greater	(262)	(570)
Total Unrealized Loss	(298)	(1,619)
ABS/CMBS
Fair value
Less than 12 months	12,833	51,091
12 Months and Greater	7,221	8,364
Total Fair value	20,054	59,455
Cost or amortized Cost
Less than 12 months	12,862	51,562
12 months and greater	7,315	8,499
Total Cost or Amortized Cost	20,177	60,061
Unrealized Loss
Less than 12 months	(29)	(471)
12 Months and Greater	(94)	(135)
Total Unrealized Loss	(123)	(606)
Corporate
Fair value
Less than 12 months	101,587	275,404
12 Months and Greater	47,606	15,174
Total Fair value	149,193	290,578
Cost or amortized Cost
Less than 12 months	105,798	285,515
12 months and greater	53,927	19,870
Total Cost or Amortized Cost	159,725	305,385
Unrealized Loss
Less than 12 months	(4,211)	(10,111)
12 Months and Greater	(6,321)	(4,696)
Total Unrealized Loss	(10,532)	(14,807)
Municipal
Fair value
Less than 12 months	1,902	8,462
12 Months and Greater		2,418
Total Fair value	1,902	10,880
Cost or amortized Cost
Less than 12 months	1,903	8,504
12 months and greater		2,424
Total Cost or Amortized Cost	1,903	10,928
Unrealized Loss
Less than 12 months	(1)	(42)
12 Months and Greater		(6)
Total Unrealized Loss	(1)	(48)
Equity securities
Fair value
Less than 12 months	8,624	16,476
Total Fair value	8,624	16,476
Cost or amortized Cost
Less than 12 months	9,395	17,932
Total Cost or Amortized Cost	9,395	17,932
Unrealized Loss
Less than 12 months	(771)	(1,456)
Total Unrealized Loss	$ (771)	$ (1,456)