Derivative Instruments (Details 1) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Change in fair value of derivatives:
Net realized investment gains (losses)	[1]	$ (1,564)	$ 70	$ (2,171)	$ 161
Change in fair value of embedded derivatives:
Net realized investment gains (losses)		$ 1,328	$ (70)	$ 1,795	$ (139)

[1] Includes the gains or losses recognized at the expiration of the option term or early termination and the changes in fair value for open options.