CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 54,233,151	$ 40,952,535
Fixed maturities, fair value	2,547,210	2,776,327
Equity securities, cost	589,221	701,951
Mortgage loans, securitizations	134	226,409
Investment real estate, accumulated depreciation	251	132
Other intangibles, accumulated amortization	197,368	140,232
Property and equipment, accumulated depreciation	$ 30,989	$ 21,305
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 (losses) on investments, income tax	$ (367,217)	$ 6,860
Net unrealized losses relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax	(6,054)	(537)
Accumulated gain (loss) - derivatives, income tax	$ (2)	$ 198