INVESTMENTS (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
INVESTMENTS
Maximum unrealized losses relative to total invested assets (as a percent)	1.00%	1.00%
Fair value
Less than 12 months	$ 530,110,000	$ 544,913,000
Greater than 12 months	2,060,000	2,947,000
Total fair value	532,170,000	547,860,000
Cost or amortized cost
Less than 12 months	540,637,000	559,946,000
Greater than 12 months	2,090,000	3,062,000
Total Cost or amortized cost	542,727,000	563,008,000
Unrealized Loss
Less than 12 months	(10,527,000)	(15,033,000)
Greater than 12 months	(30,000)	(115,000)
Total Unrealized Loss	(10,557,000)	(15,148,000)
Fair value of trading securities	100,000	100,000
Debt securities
Fair value
Less than 12 months	515,398,000	538,835,000
Greater than 12 months	2,060,000	2,947,000
Total fair value	517,458,000	541,782,000
Cost or amortized cost
Less than 12 months	524,300,000	553,574,000
Greater than 12 months	2,090,000	3,062,000
Total Cost or amortized cost	526,390,000	556,636,000
Unrealized Loss
Less than 12 months	(8,902,000)	(14,739,000)
Greater than 12 months	(30,000)	(115,000)
Total Unrealized Loss	(8,932,000)	(14,854,000)
Treasuries
Fair value
Less than 12 months	4,816,000	5,689,000
Total fair value	4,816,000	5,689,000
Cost or amortized cost
Less than 12 months	4,899,000	5,880,000
Total Cost or amortized cost	4,899,000	5,880,000
Unrealized Loss
Less than 12 months	(83,000)	(191,000)
Total Unrealized Loss	(83,000)	(191,000)
Agencies
Fair value
Less than 12 months	316,693,000	295,897,000
Total fair value	316,693,000	295,897,000
Cost or amortized cost
Less than 12 months	321,780,000	304,374,000
Total Cost or amortized cost	321,780,000	304,374,000
Unrealized Loss
Less than 12 months	(5,087,000)	(8,477,000)
Total Unrealized Loss	(5,087,000)	(8,477,000)
Mortgage-backed
Fair value
Less than 12 months	48,778,000	43,852,000
Total fair value	48,778,000	43,852,000
Cost or amortized cost
Less than 12 months	49,296,000	44,659,000
Total Cost or amortized cost	49,296,000	44,659,000
Unrealized Loss
Less than 12 months	(518,000)	(807,000)
Total Unrealized Loss	(518,000)	(807,000)
ABS/CMO
Fair value
Less than 12 months	9,272,000	2,160,000
Total fair value	9,272,000	2,160,000
Cost or amortized cost
Less than 12 months	9,347,000	2,196,000
Total Cost or amortized cost	9,347,000	2,196,000
Unrealized Loss
Less than 12 months	(75,000)	(36,000)
Total Unrealized Loss	(75,000)	(36,000)
Corporate
Fair value
Less than 12 months	87,985,000	110,772,000
Greater than 12 months		1,951,000
Total fair value	87,985,000	112,723,000
Cost or amortized cost
Less than 12 months	90,514,000	113,813,000
Greater than 12 months		2,012,000
Total Cost or amortized cost	90,514,000	115,825,000
Unrealized Loss
Less than 12 months	(2,529,000)	(3,041,000)
Greater than 12 months		(61,000)
Total Unrealized Loss	(2,529,000)	(3,102,000)
Municipals
Fair value
Less than 12 months	47,854,000	80,465,000
Greater than 12 months	2,060,000	996,000
Total fair value	49,914,000	81,461,000
Cost or amortized cost
Less than 12 months	48,464,000	82,652,000
Greater than 12 months	2,090,000	1,050,000
Total Cost or amortized cost	50,554,000	83,702,000
Unrealized Loss
Less than 12 months	(610,000)	(2,187,000)
Greater than 12 months	(30,000)	(54,000)
Total Unrealized Loss	(640,000)	(2,241,000)
Common Stock
Fair value
Less than 12 months	14,712,000	6,078,000
Total fair value	14,712,000	6,078,000
Cost or amortized cost
Less than 12 months	16,337,000	6,372,000
Total Cost or amortized cost	16,337,000	6,372,000
Unrealized Loss
Less than 12 months	(1,625,000)	(294,000)
Total Unrealized Loss	$ (1,625,000)	$ (294,000)