INCOME TAXES (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective income tax rate related to continuing operations
Statutory federal income tax rate applied to pre-tax income (as a percent)	35.00%	35.00%	35.00%
State income taxes (as a percent)	0.50%	0.40%	0.40%
Investment income not subject to tax (as a percent)	(2.70%)	(4.40%)	(3.10%)
Uncertain tax positions (as a percent)	0.50%	0.10%	0.20%
Other (as a percent)	0.10%	(0.10%)	0.40%
Effective income tax rate (as a percent)	33.40%	31.00%	32.90%
Current income tax expense:
Federal	$ 176,238,000	$ (18,076,000)	$ 78,510,000
State	5,525,000	(222,000)	2,496,000
Total current	181,763,000	(18,298,000)	81,006,000
Deferred income tax expense:
Federal	65,566,000	149,288,000	66,375,000
State	(491,000)	(93,000)	3,662,000
Total deferred	65,075,000	149,195,000	70,037,000
Deferred income tax assets:
Premium receivables and policy liabilities	154,720,000	275,355,000
Loss and credit carryforwards	35,642,000	104,530,000
Deferred compensation	104,117,000	104,062,000
Invested assets (other than unrealized gains)	2,960,000
Valuation allowance	(791,000)	(780,000)
Deferred income tax assets	296,648,000	483,167,000
Deferred income tax liabilities:
Deferred policy acquisition costs and value of business acquired	1,073,499,000	1,034,614,000
Invested assets (other than realized gains)		147,446,000
Net unrealized gains (losses) on investments	798,529,000	290,062,000
Other	36,484,000	52,465,000
Deferred income tax liabilities	1,908,512,000	1,524,587,000
Net deferred income tax (liability) asset	(1,611,864,000)	(1,041,420,000)
State operating loss carryforwards, valuation allowance	1,200,000	1,200,000
Change in valuation allowance, before federal income taxes	$ 0