CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Fixed maturities, at fair value, amortized cost	$ 63,659,719	$ 54,466,305
Fixed maturities, at amortized cost, fair value	2,685,076	2,547,210
Equity securities, cost	604,474	627,087
Mortgage loans, related to securitizations	0	134
Investment real estate, net of accumulated depreciation	350	251
Other intangibles, net of accumulated amortization	239,846	197,583
Property and equipment, net of accumulated depreciation	$ 44,346	$ 33,199
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	5,000	5,000
Common stock, shares issued (in shares)	1,000	1,000
Net unrealized gains (losses) on investments, net of income tax	$ 423,248	$ (368,830)
Net unrealized losses relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax	(4,908)	(6,054)
Accumulated gain (loss) - derivatives, income tax	(1,873)	(2)
Postretirement benefits liability adjustment, income tax	$ (4,112)	$ (4,112)