Investments - Schedule of Realized Gain (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Gross gains realized	$ 63	$ 0	$ 1,477
Gross losses realized	(40)	0	(182)
Proceeds from sales	$ 41,069	$ 0	$ 159,604