ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Reclassifications out of accumulated other comprehensive income
Benefits and settlement expenses, net of reinsurance ceded	$ (557,866)	$ (568,522)	$ (1,139,746)	$ (1,158,151)
Realized investment gains (losses): All other investments	(109,978)	65,593	(114,123)	101,319
Net impairment losses recognized in earnings	(4,000)	(13,608)	(8,584)	(32,372)
Income before income tax	157,013	107,687	274,640	258,266
Tax (expense) or benefit	(53,814)	(31,532)	(93,150)	(83,090)
Net income	103,199	76,155	181,490	175,176
Gains and losses on derivative instruments | Amount Reclassified from Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income
Benefits and settlement expenses, net of reinsurance ceded	(580)		(1,077)
Income before income tax	(580)		(1,077)
Tax (expense) or benefit	203		377
Net income	(377)		(700)
Unrealized gains and losses on available-for-sale securities | Amount Reclassified from Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income
Realized investment gains (losses): All other investments	21,518		33,828
Net impairment losses recognized in earnings	(4,000)		(8,584)
Income before income tax	17,518		25,244
Tax (expense) or benefit	(6,131)		(8,835)
Net income	$ 11,387		$ 16,409