INVESTMENTS Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Investment positions with unrealized losses
Unrealized losses relative to total invested assets (as a percent)	0.80%
Fair value
Less than 12 months	$ 363,749	$ 227,874
12 Months and Greater	37,741	106,657
Total Fair value	401,490	334,531
Cost or amortized Cost
Less than 12 months	375,883	233,338
12 months and greater	41,729	108,312
Total Cost or Amortized Cost	417,612	341,650
Unrealized Loss
Less than 12 months	(12,134)	(5,464)
12 Months and Greater	(3,988)	(1,655)
Total Unrealized Loss	(16,122)	(7,119)
Debt securities
Fair value
Less than 12 months	335,728	217,037
12 Months and Greater	37,741	106,657
Total Fair value	373,469	323,694
Cost or amortized Cost
Less than 12 months	344,935	221,503
12 months and greater	41,729	108,312
Total Cost or Amortized Cost	386,664	329,815
Unrealized Loss
Less than 12 months	(9,207)	(4,466)
12 Months and Greater	(3,988)	(1,655)
Total Unrealized Loss	$ (13,195)	(6,121)
Percent to Total	100.00%
Debt securities | NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Fair value
Total Fair value	$ 228,112
Cost or amortized Cost
Total Cost or Amortized Cost	232,521
Unrealized Loss
Total Unrealized Loss	$ (4,409)
Percent to Total	33.40%
Debt securities | NAIC Rating 2 | BBB | Baa
Fair value
Total Fair value	$ 83,492
Cost or amortized Cost
Total Cost or Amortized Cost	88,387
Unrealized Loss
Total Unrealized Loss	$ (4,895)
Percent to Total	37.10%
Debt securities | NAIC Rating 3 | BB | Ba
Fair value
Total Fair value	$ 31,700
Cost or amortized Cost
Total Cost or Amortized Cost	33,320
Unrealized Loss
Total Unrealized Loss	$ (1,620)
Percent to Total	12.30%
Debt securities | NAIC Rating 4 | B
Fair value
Total Fair value	$ 29,677
Cost or amortized Cost
Total Cost or Amortized Cost	31,846
Unrealized Loss
Total Unrealized Loss	$ (2,169)
Percent to Total	16.40%
Debt securities | NAIC Rating 5 | CCC or lower
Fair value
Total Fair value	$ 488
Cost or amortized Cost
Total Cost or Amortized Cost	590
Unrealized Loss
Total Unrealized Loss	$ (102)
Percent to Total	0.80%
U.S. government
Fair value
Less than 12 months		4,416
Total Fair value		4,416
Cost or amortized Cost
Less than 12 months		4,427
Total Cost or Amortized Cost		4,427
Unrealized Loss
Less than 12 months		(11)
Total Unrealized Loss		(11)
U.S. Agency
Fair value
Less than 12 months	$ 2,073
Total Fair value	2,073
Cost or amortized Cost
Less than 12 months	2,091
Total Cost or Amortized Cost	2,091
Unrealized Loss
Less than 12 months	(18)
Total Unrealized Loss	(18)
Non-U.S. govt. & agency
Fair value
Less than 12 months	4,664
Total Fair value	4,664
Cost or amortized Cost
Less than 12 months	5,042
Total Cost or Amortized Cost	5,042
Unrealized Loss
Less than 12 months	(378)
Total Unrealized Loss	(378)
Agency MBS
Fair value
Less than 12 months	43,665	12,840
12 Months and Greater	19,294	61,534
Total Fair value	62,959	74,374
Cost or amortized Cost
Less than 12 months	43,841	12,947
12 months and greater	19,657	62,803
Total Cost or Amortized Cost	63,498	75,750
Unrealized Loss
Less than 12 months	(176)	(107)
12 Months and Greater	(363)	(1,269)
Total Unrealized Loss	(539)	(1,376)
ABS/CMBS
Fair value
Less than 12 months	18,525	63,782
12 Months and Greater	2,571	11,616
Total Fair value	21,096	75,398
Cost or amortized Cost
Less than 12 months	18,675	64,084
12 months and greater	2,593	11,725
Total Cost or Amortized Cost	21,268	75,809
Unrealized Loss
Less than 12 months	(150)	(302)
12 Months and Greater	(22)	(109)
Total Unrealized Loss	(172)	(411)
Corporate
Fair value
Less than 12 months	214,761	123,617
12 Months and Greater	15,876	14,488
Total Fair value	230,637	138,105
Cost or amortized Cost
Less than 12 months	222,647	127,634
12 months and greater	19,479	14,661
Total Cost or Amortized Cost	242,126	142,295
Unrealized Loss
Less than 12 months	(7,886)	(4,017)
12 Months and Greater	(3,603)	(173)
Total Unrealized Loss	(11,489)	(4,190)
Municipal
Fair value
Less than 12 months	52,040	12,382
12 Months and Greater		19,019
Total Fair value	52,040	31,401
Cost or amortized Cost
Less than 12 months	52,639	12,411
12 months and greater		19,123
Total Cost or Amortized Cost	52,639	31,534
Unrealized Loss
Less than 12 months	(599)	(29)
12 Months and Greater		(104)
Total Unrealized Loss	(599)	(133)
Equity securities
Fair value
Less than 12 months	28,021	10,837
Total Fair value	28,021	10,837
Cost or amortized Cost
Less than 12 months	30,948	11,835
Total Cost or Amortized Cost	30,948	11,835
Unrealized Loss
Less than 12 months	(2,927)	(998)
Total Unrealized Loss	$ (2,927)	$ (998)