Investments (Net Unrealized Gain (Loss) on Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Gross unrealized gains	$ 17,678	$ 93,034
Gross unrealized losses	(80,263)	(10,856)
Deferred policy acquisition costs and sales inducements	24,237	(39,579)
Deferred Federal income tax expense	8,053	(8,946)
Adjustments for deferred expense, deferred policy acquisition and sales inducement cost	(30,295)	33,653
Net unrealized gains related to securities transferred to held to maturity	0	0
Net unrealized gains (losses) on investment securities	$ (30,295)	$ 33,653