Derivative Instruments (Details 1) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Change in fair value of derivatives:
Net realized investment gains (losses)	[1]	$ (402)	$ 77	$ (607)	$ 91
Change in fair value of embedded derivatives:
Net realized investment gains (losses)		$ 28	$ (57)	$ 467	$ (69)

[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.