Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Fixed maturities, available-for-sale, amortized cost (in dollars)	$ 20,007,462	$ 18,953,144
Fixed maturities, held for trading, amortized cost (in dollars)	612,899	331,081
Mortgage loans on real estate, allowances (in dollars)	2,890	2,890
Short-term investments, available-for-sale, amortized cost (in dollars)	$ 267,026	$ 263,501
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	7,232,986	7,032,000
Common stock, shares outstanding	7,232,986	7,032,000