Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value of Financial Instruments (Textual) [Abstract]
Realized loss on impairment of securities			$ 1,714
Level 3
Fair Value of Financial Instruments (Textual) [Abstract]
Percentage of invested assets in total investment portfolio Level 3 recurring	3.10%		3.10%
Net realized investment losses	$ 1,238	$ 1,324	$ 3,546	$ 1,998