Derivative Investments (Statements of Earnings) (Details) (Derivatives Not Designated as Hedging Instruments [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (554)	$ (1,242)	$ 275	$ (2,886)
Equity Index Options [Member] | Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	3,479	35,615	49,278	126,739
Fixed-Index Products [Member] | Universal Life and Annuity Contract Interest [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (4,033)	$ (36,857)	$ (49,003)	$ (129,625)