ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassifications out of accumulated other comprehensive income (loss)
Benefits and settlement expenses, net of reinsurance ceded	$ (624,577)	$ (629,945)	$ (1,764,323)	$ (1,788,096)
Realized investment gains (losses): All other investments	(19,508)	122,555	(133,631)	223,874
Net impairment losses recognized in earnings	(8,681)	(8,556)	(17,265)	(40,928)
Income before income tax	142,121	90,986	416,761	349,252
Tax (expense) or benefit	(49,060)	(30,506)	(142,210)	(113,596)
Net income	93,061	60,480	274,551	235,656
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	(572)		(1,649)
Income before income tax	(572)		(1,649)
Tax (expense) or benefit	200		577
Net income	(372)		(1,072)
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	10,546		44,374
Net impairment losses recognized in earnings	(8,681)		(17,265)
Income before income tax	1,865		27,109
Tax (expense) or benefit	(653)		(9,488)
Net income	$ 1,212		$ 17,621