INVESTMENTS Unrealized Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investment positions with unrealized losses
Unrealized losses relative to total invested assets (as a percent)	0.70%
Fair value
Less than 12 months	$ 525,036	$ 227,874
12 Months and Greater	34,089	106,657
Total Fair value	559,125	334,531
Cost or amortized Cost
Less than 12 months	538,523	233,338
12 months and greater	35,249	108,312
Total Cost or Amortized Cost	573,772	341,650
Unrealized Loss
Less than 12 months	(13,487)	(5,464)
12 Months and Greater	(1,160)	(1,655)
Total Unrealized Loss	(14,647)	(7,119)
Debt securities
Fair value
Less than 12 months	510,809	217,037
12 Months and Greater	34,089	106,657
Total Fair value	544,898	323,694
Cost or amortized Cost
Less than 12 months	523,193	221,503
12 months and greater	35,249	108,312
Total Cost or Amortized Cost	558,442	329,815
Unrealized Loss
Less than 12 months	(12,384)	(4,466)
12 Months and Greater	(1,160)	(1,655)
Total Unrealized Loss	$ (13,544)	(6,121)
Percent to Total	100.00%
Debt securities | NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Fair value
Total Fair value	$ 414,108
Cost or amortized Cost
Total Cost or Amortized Cost	422,894
Unrealized Loss
Total Unrealized Loss	$ (8,786)
Percent to Total	64.90%
Debt securities | NAIC Rating 2 | BBB | Baa
Fair value
Total Fair value	$ 86,789
Cost or amortized Cost
Total Cost or Amortized Cost	90,037
Unrealized Loss
Total Unrealized Loss	$ (3,248)
Percent to Total	24.00%
Debt securities | NAIC Rating 3 | BB | Ba
Fair value
Total Fair value	$ 25,368
Cost or amortized Cost
Total Cost or Amortized Cost	26,131
Unrealized Loss
Total Unrealized Loss	$ (763)
Percent to Total	5.60%
Debt securities | NAIC Rating 4 | B
Fair value
Total Fair value	$ 18,512
Cost or amortized Cost
Total Cost or Amortized Cost	19,243
Unrealized Loss
Total Unrealized Loss	$ (731)
Percent to Total	5.40%
Debt securities | NAIC Rating 5 | CCC or lower
Fair value
Total Fair value	$ 121
Cost or amortized Cost
Total Cost or Amortized Cost	137
Unrealized Loss
Total Unrealized Loss	$ (16)
Percent to Total	0.10%
U.S. government
Fair value
Less than 12 months	$ 5,307	4,416
Total Fair value	5,307	4,416
Cost or amortized Cost
Less than 12 months	5,317	4,427
Total Cost or Amortized Cost	5,317	4,427
Unrealized Loss
Less than 12 months	(10)	(11)
Total Unrealized Loss	(10)	(11)
U.S. Agency
Fair value
Less than 12 months	7,026
Total Fair value	7,026
Cost or amortized Cost
Less than 12 months	7,110
Total Cost or Amortized Cost	7,110
Unrealized Loss
Less than 12 months	(84)
Total Unrealized Loss	(84)
Non-U.S. govt. & agency
Fair value
Less than 12 months	1,840
Total Fair value	1,840
Cost or amortized Cost
Less than 12 months	1,893
Total Cost or Amortized Cost	1,893
Unrealized Loss
Less than 12 months	(53)
Total Unrealized Loss	(53)
Agency MBS
Fair value
Less than 12 months	60,153	12,840
12 Months and Greater	20,107	61,534
Total Fair value	80,260	74,374
Cost or amortized Cost
Less than 12 months	60,974	12,947
12 months and greater	20,669	62,803
Total Cost or Amortized Cost	81,643	75,750
Unrealized Loss
Less than 12 months	(821)	(107)
12 Months and Greater	(562)	(1,269)
Total Unrealized Loss	(1,383)	(1,376)
ABS/CMBS
Fair value
Less than 12 months	31,524	63,782
12 Months and Greater	4,157	11,616
Total Fair value	35,681	75,398
Cost or amortized Cost
Less than 12 months	31,845	64,084
12 months and greater	4,180	11,725
Total Cost or Amortized Cost	36,025	75,809
Unrealized Loss
Less than 12 months	(321)	(302)
12 Months and Greater	(23)	(109)
Total Unrealized Loss	(344)	(411)
Corporate
Fair value
Less than 12 months	230,965	123,617
12 Months and Greater	9,825	14,488
Total Fair value	240,790	138,105
Cost or amortized Cost
Less than 12 months	239,010	127,634
12 months and greater	10,400	14,661
Total Cost or Amortized Cost	249,410	142,295
Unrealized Loss
Less than 12 months	(8,045)	(4,017)
12 Months and Greater	(575)	(173)
Total Unrealized Loss	(8,620)	(4,190)
Municipal
Fair value
Less than 12 months	173,994	12,382
12 Months and Greater		19,019
Total Fair value	173,994	31,401
Cost or amortized Cost
Less than 12 months	177,044	12,411
12 months and greater		19,123
Total Cost or Amortized Cost	177,044	31,534
Unrealized Loss
Less than 12 months	(3,050)	(29)
12 Months and Greater		(104)
Total Unrealized Loss	(3,050)	(133)
Equity securities
Fair value
Less than 12 months	14,227	10,837
Total Fair value	14,227	10,837
Cost or amortized Cost
Less than 12 months	15,330	11,835
Total Cost or Amortized Cost	15,330	11,835
Unrealized Loss
Less than 12 months	(1,103)	(998)
Total Unrealized Loss	$ (1,103)	$ (998)