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 (Loss)
Benefits and settlement expenses, net of reinsurance ceded	$ (555,894)	$ (565,414)	$ (1,136,870)	$ (1,152,423)
Realized investment gains (losses): All other investments	(110,227)	67,879	(114,473)	103,362
Net impairment losses recognized in earnings	(4,000)	(13,442)	(8,584)	(32,038)
Income before income tax	78,927	117,065	188,741	258,133
Tax (expense) or benefit	(25,923)	(35,438)	(61,859)	(80,650)
Gains and losses on derivative instruments | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
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 of tax	(377)		(700)
Unrealized gains and losses on available-for-sale securities | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Realized investment gains (losses): All other investments	21,658		33,957
Net impairment losses recognized in earnings	(4,000)		(8,584)
Income before income tax	17,658		25,373
Tax (expense) or benefit	(6,180)		(8,880)
Net of tax	$ 11,478		$ 16,493