Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value of Financial Instruments (Textual) [Abstract]
Net realized investment gains (losses) included in net income related to financial assets	$ 0	$ (246)	$ 0	$ (243)
Level 3
Fair Value of Financial Instruments (Textual) [Abstract]
Percentage of invested assets in total investment portfolio Level 3 recurring	4.00%		4.00%
Net realized investment losses	$ (371)	$ (1,291)	$ (4,705)	$ (3,513)