INVESTMENTS (DETAILS 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net Investment Income [Line Items]
Gross investment income	$ 81,007	$ 107,048	$ 203,936	$ 224,304
Investment expenses	(6,558)	(7,030)	(13,464)	(13,631)
Net investment income	74,449	100,018	190,472	210,673
Fixed Maturities [Member]
Net Investment Income [Line Items]
Gross investment income	76,544	89,203	156,181	177,784
Equity Securities [Member]
Net Investment Income [Line Items]
Gross investment income	5,071	4,074	6,180	4,898
Other Investments [Member]
Net Investment Income [Line Items]
Gross investment income	(2,304)	11,797	38,116	37,108
Cash And Cash Equivalents [Member]
Net Investment Income [Line Items]
Gross investment income	1,663	1,502	3,271	3,655
Short-term Investments [Member]
Net Investment Income [Line Items]
Gross investment income	$ 33	$ 472	$ 188	$ 859