ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Reclassifications out of accumulated other comprehensive income
Benefits and settlement expenses, net of reinsurance ceded	$ (581,880)	$ (589,629)
Realized investment gains (losses): All other investments	(4,145)	35,726
Net impairment losses recognized in earnings	(4,584)	(18,764)
Income before income tax	117,627	150,579
Tax (expense) or benefit	(39,336)	(51,558)
Net income	78,291	99,021
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	(497)
Income before income tax	(497)
Tax (expense) or benefit	174
Net income	(323)
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	12,310
Net impairment losses recognized in earnings	(4,584)
Income before income tax	7,726
Tax (expense) or benefit	(2,704)
Net income	$ 5,022