Investments (Details 1) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Amortized Cost
One year or less	$ 1,817
More than one to five years	14,298
More than five to ten years	7,583
More than ten years	9,174
Total	32,872	$ 26,793
Estimated Fair Value
One year or less	1,818
More than one to five years	14,255
More than five to ten years	7,559
More than ten years	9,074
Total	$ 32,706	$ 26,559