CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 40,952,535	$ 39,645,111
Fixed maturities, fair value	2,776,327	2,733,340
Equity securities, cost	701,951	729,951
Mortgage loans, securitizations	226,409	277,964
Investment real estate, accumulated depreciation	132	252
Other intangibles, accumulated depreciation	140,232	79,183
Property and equipment, accumulated depreciation	$ 21,305	$ 16,573
Preferred Stock, par value (in dollars per share)	$ 1	$ 1
Preferred Stock, shares authorized (in shares)	2,000	2,000
Preferred Stock, Liquidation preference	$ 2,000	$ 2,000
Common Stock, par value (in dollars per share)	$ 1	$ 1
Common Stock, shares authorized (in shares)	5,000,000	5,000,000
Common Stock, shares issued (in shares)	5,000,000	5,000,000
Net unrealized gains on investments, income tax	$ 6,138	$ (349,242)
Net unrealized gains relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax	(6)	(3,864)
Accumulated loss - derivatives, income tax	$ 198	$ 391