Statements of Financial Position (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Fixed maturities, available-for-sale, amortized cost	$ 12,465,746	$ 10,186,465
Fixed Maturities, Trading, Amortized Cost	349,428	294,549
Equity securities, at cost	63,647	18,765
Other invested assets, fair value	$ 10,492	$ 50,945
Common stock, par value (in dollars per share)	$ 100	$ 100
Common stock, shares authorized	25,000	25,000
Common stock, shares issued	25,000	25,000
Common stock, shares outstanding	25,000	25,000