Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unrecognized Tax Benefits [Roll Forward]
Beginning of year balance	$ 613	$ 566	$ 445
Additions for tax positions of prior years	0	8	62
Additions for tax positions of the current year	0	39	59
End of year balance	$ 613	$ 613	$ 566