ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)
Benefits and settlement expenses, net of reinsurance ceded	$ (727,428)	$ (580,976)
Realized investment gains (losses): All other investments	72,146	(4,246)
Net impairment losses recognized in earnings	(1,591)	(4,584)
Income before income tax	151,611	109,814
Tax (expense) or benefit	(49,062)	(35,936)
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	(670)	(497)
Income before income tax	(670)	(497)
Tax (expense) or benefit	234	174
Net of tax	(436)	(323)
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	7,370	12,299
Net impairment losses recognized in earnings	(1,591)	(4,584)
Income before income tax	5,779	7,715
Tax (expense) or benefit	(2,023)	(2,700)
Net of tax	$ 3,756	$ 5,015