INVESTMENTS (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
INVESTMENTS
Maximum unrealized losses relative to total invested assets (as a percent)	1.00%	1.00%
Fair value
Less than 12 months	$ 302,055	$ 80,439
Greater than 12 months	22,339	29,748
Total fair value	324,394	110,187
Cost or amortized cost
Less than 12 months	308,780	85,421
Greater than 12 months	23,107	31,419
Total Cost or amortized cost	331,887	116,840
Unrealized Loss
Less than 12 months	(6,725)	(4,982)
Greater than 12 months	(768)	(1,671)
Total Unrealized Loss	(7,493)	(6,653)
Maximum
Unrealized Loss
Fair value of trading securities	100	100
U.S Government
Fair value
Less than 12 months	5,009	5,023
Total fair value	5,009	5,023
Cost or amortized cost
Less than 12 months	5,028	5,031
Total Cost or amortized cost	5,028	5,031
Unrealized Loss
Less than 12 months	(19)	(8)
Total Unrealized Loss	(19)	(8)
U.S. Agency
Fair value
Less than 12 months	115,302
Total fair value	115,302
Cost or amortized cost
Less than 12 months	117,151
Total Cost or amortized cost	117,151
Unrealized Loss
Less than 12 months	(1,849)
Total Unrealized Loss	(1,849)
Non-U.S. govt. & agency
Fair value
Less than 12 months	1,946
Total fair value	1,946
Cost or amortized cost
Less than 12 months	1,952
Total Cost or amortized cost	1,952
Unrealized Loss
Less than 12 months	(6)
Total Unrealized Loss	(6)
ABS/CMO
Fair value
Less than 12 months	13,055
Total fair value	13,055
Cost or amortized cost
Less than 12 months	13,106
Total Cost or amortized cost	13,106
Unrealized Loss
Less than 12 months	(51)
Total Unrealized Loss	(51)
Corporate
Fair value
Less than 12 months	102,435	49,464
Greater than 12 months	21,273	28,698
Total fair value	123,708	78,162
Cost or amortized cost
Less than 12 months	104,539	51,894
Greater than 12 months	22,040	30,351
Total Cost or amortized cost	126,579	82,245
Unrealized Loss
Less than 12 months	(2,104)	(2,430)
Greater than 12 months	(767)	(1,653)
Total Unrealized Loss	(2,871)	(4,083)
States, political subdivisions, and revenues
Fair value
Less than 12 months	49,916
Greater than 12 months	1,066	1,050
Total fair value	50,982	1,050
Cost or amortized cost
Less than 12 months	51,130
Greater than 12 months	1,067	1,068
Total Cost or amortized cost	52,197	1,068
Unrealized Loss
Less than 12 months	(1,214)
Greater than 12 months	(1)	(18)
Total Unrealized Loss	(1,215)	(18)
Subtotal, debt securities
Fair value
Less than 12 months	287,663	54,487
Greater than 12 months	22,339	29,748
Total fair value	310,002	84,235
Cost or amortized cost
Less than 12 months	292,906	56,925
Greater than 12 months	23,107	31,419
Total Cost or amortized cost	316,013	88,344
Unrealized Loss
Less than 12 months	(5,243)	(2,438)
Greater than 12 months	(768)	(1,671)
Total Unrealized Loss	(6,011)	(4,109)
Common Stock
Fair value
Less than 12 months	14,392	25,952
Total fair value	14,392	25,952
Cost or amortized cost
Less than 12 months	15,874	28,496
Total Cost or amortized cost	15,874	28,496
Unrealized Loss
Less than 12 months	(1,482)	(2,544)
Total Unrealized Loss	$ (1,482)	$ (2,544)